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c97eb679ef
As a demonstration, the lguest launcher is pretty strict, trying to catch badly behaved drivers. Document this precisely. A good implementation would *NOT* crash the guest when these happened! Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
3093 lines
85 KiB
C
3093 lines
85 KiB
C
/*P:100
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* This is the Launcher code, a simple program which lays out the "physical"
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* memory for the new Guest by mapping the kernel image and the virtual
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* devices, then opens /dev/lguest to tell the kernel about the Guest and
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* control it.
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:*/
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#define _LARGEFILE64_SOURCE
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <err.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <elf.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <sys/eventfd.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <ctype.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <sys/time.h>
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#include <time.h>
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#include <netinet/in.h>
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#include <net/if.h>
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#include <linux/sockios.h>
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#include <linux/if_tun.h>
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#include <sys/uio.h>
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#include <termios.h>
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#include <getopt.h>
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#include <assert.h>
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#include <sched.h>
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#include <limits.h>
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#include <stddef.h>
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#include <signal.h>
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#include <pwd.h>
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#include <grp.h>
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#include <sys/user.h>
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#include <linux/pci_regs.h>
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#ifndef VIRTIO_F_ANY_LAYOUT
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#define VIRTIO_F_ANY_LAYOUT 27
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#endif
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/*L:110
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* We can ignore the 43 include files we need for this program, but I do want
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* to draw attention to the use of kernel-style types.
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*
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* As Linus said, "C is a Spartan language, and so should your naming be." I
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* like these abbreviations, so we define them here. Note that u64 is always
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* unsigned long long, which works on all Linux systems: this means that we can
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* use %llu in printf for any u64.
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*/
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typedef unsigned long long u64;
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typedef uint32_t u32;
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typedef uint16_t u16;
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typedef uint8_t u8;
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/*:*/
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#define VIRTIO_CONFIG_NO_LEGACY
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#define VIRTIO_PCI_NO_LEGACY
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#define VIRTIO_BLK_NO_LEGACY
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/* Use in-kernel ones, which defines VIRTIO_F_VERSION_1 */
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#include "../../include/uapi/linux/virtio_config.h"
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#include "../../include/uapi/linux/virtio_net.h"
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#include "../../include/uapi/linux/virtio_blk.h"
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#include "../../include/uapi/linux/virtio_console.h"
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#include "../../include/uapi/linux/virtio_rng.h"
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#include <linux/virtio_ring.h>
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#include "../../include/uapi/linux/virtio_pci.h"
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#include <asm/bootparam.h>
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#include "../../include/linux/lguest_launcher.h"
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#define BRIDGE_PFX "bridge:"
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#ifndef SIOCBRADDIF
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#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
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#endif
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/* We can have up to 256 pages for devices. */
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#define DEVICE_PAGES 256
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/* This will occupy 3 pages: it must be a power of 2. */
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#define VIRTQUEUE_NUM 256
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/*L:120
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* verbose is both a global flag and a macro. The C preprocessor allows
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* this, and although I wouldn't recommend it, it works quite nicely here.
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*/
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static bool verbose;
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#define verbose(args...) \
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do { if (verbose) printf(args); } while(0)
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/*:*/
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/* The pointer to the start of guest memory. */
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static void *guest_base;
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/* The maximum guest physical address allowed, and maximum possible. */
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static unsigned long guest_limit, guest_max, guest_mmio;
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/* The /dev/lguest file descriptor. */
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static int lguest_fd;
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/* a per-cpu variable indicating whose vcpu is currently running */
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static unsigned int __thread cpu_id;
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/* 5 bit device number in the PCI_CONFIG_ADDR => 32 only */
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#define MAX_PCI_DEVICES 32
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/* This is our list of devices. */
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struct device_list {
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/* Counter to assign interrupt numbers. */
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unsigned int next_irq;
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/* Counter to print out convenient device numbers. */
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unsigned int device_num;
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/* PCI devices. */
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struct device *pci[MAX_PCI_DEVICES];
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};
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/* The list of Guest devices, based on command line arguments. */
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static struct device_list devices;
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struct virtio_pci_cfg_cap {
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struct virtio_pci_cap cap;
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u32 pci_cfg_data; /* Data for BAR access. */
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};
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struct virtio_pci_mmio {
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struct virtio_pci_common_cfg cfg;
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u16 notify;
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u8 isr;
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u8 padding;
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/* Device-specific configuration follows this. */
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};
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/* This is the layout (little-endian) of the PCI config space. */
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struct pci_config {
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u16 vendor_id, device_id;
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u16 command, status;
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u8 revid, prog_if, subclass, class;
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u8 cacheline_size, lat_timer, header_type, bist;
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u32 bar[6];
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u32 cardbus_cis_ptr;
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u16 subsystem_vendor_id, subsystem_device_id;
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u32 expansion_rom_addr;
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u8 capabilities, reserved1[3];
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u32 reserved2;
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u8 irq_line, irq_pin, min_grant, max_latency;
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/* Now, this is the linked capability list. */
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struct virtio_pci_cap common;
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struct virtio_pci_notify_cap notify;
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struct virtio_pci_cap isr;
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struct virtio_pci_cap device;
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struct virtio_pci_cfg_cap cfg_access;
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};
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/* The device structure describes a single device. */
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struct device {
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/* The name of this device, for --verbose. */
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const char *name;
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/* Any queues attached to this device */
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struct virtqueue *vq;
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/* Is it operational */
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bool running;
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/* PCI configuration */
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union {
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struct pci_config config;
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u32 config_words[sizeof(struct pci_config) / sizeof(u32)];
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};
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/* Features we offer, and those accepted. */
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u64 features, features_accepted;
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/* Device-specific config hangs off the end of this. */
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struct virtio_pci_mmio *mmio;
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/* PCI MMIO resources (all in BAR0) */
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size_t mmio_size;
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u32 mmio_addr;
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/* Device-specific data. */
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void *priv;
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};
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/* The virtqueue structure describes a queue attached to a device. */
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struct virtqueue {
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struct virtqueue *next;
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/* Which device owns me. */
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struct device *dev;
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/* The actual ring of buffers. */
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struct vring vring;
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/* The information about this virtqueue (we only use queue_size on) */
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struct virtio_pci_common_cfg pci_config;
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/* Last available index we saw. */
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u16 last_avail_idx;
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/* How many are used since we sent last irq? */
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unsigned int pending_used;
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/* Eventfd where Guest notifications arrive. */
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int eventfd;
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/* Function for the thread which is servicing this virtqueue. */
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void (*service)(struct virtqueue *vq);
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pid_t thread;
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};
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/* Remember the arguments to the program so we can "reboot" */
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static char **main_args;
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/* The original tty settings to restore on exit. */
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static struct termios orig_term;
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/*
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* We have to be careful with barriers: our devices are all run in separate
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* threads and so we need to make sure that changes visible to the Guest happen
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* in precise order.
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*/
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#define wmb() __asm__ __volatile__("" : : : "memory")
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#define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
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#define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
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/* Wrapper for the last available index. Makes it easier to change. */
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#define lg_last_avail(vq) ((vq)->last_avail_idx)
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/*
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* The virtio configuration space is defined to be little-endian. x86 is
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* little-endian too, but it's nice to be explicit so we have these helpers.
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*/
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#define cpu_to_le16(v16) (v16)
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#define cpu_to_le32(v32) (v32)
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#define cpu_to_le64(v64) (v64)
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#define le16_to_cpu(v16) (v16)
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#define le32_to_cpu(v32) (v32)
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#define le64_to_cpu(v64) (v64)
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/* Is this iovec empty? */
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static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
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{
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unsigned int i;
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for (i = 0; i < num_iov; i++)
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if (iov[i].iov_len)
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return false;
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return true;
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}
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/* Take len bytes from the front of this iovec. */
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static void iov_consume(struct iovec iov[], unsigned num_iov,
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void *dest, unsigned len)
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{
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unsigned int i;
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for (i = 0; i < num_iov; i++) {
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unsigned int used;
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used = iov[i].iov_len < len ? iov[i].iov_len : len;
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if (dest) {
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memcpy(dest, iov[i].iov_base, used);
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dest += used;
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}
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iov[i].iov_base += used;
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iov[i].iov_len -= used;
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len -= used;
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}
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if (len != 0)
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errx(1, "iovec too short!");
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}
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/*L:100
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* The Launcher code itself takes us out into userspace, that scary place where
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* pointers run wild and free! Unfortunately, like most userspace programs,
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* it's quite boring (which is why everyone likes to hack on the kernel!).
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* Perhaps if you make up an Lguest Drinking Game at this point, it will get
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* you through this section. Or, maybe not.
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*
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* The Launcher sets up a big chunk of memory to be the Guest's "physical"
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* memory and stores it in "guest_base". In other words, Guest physical ==
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* Launcher virtual with an offset.
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*
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* This can be tough to get your head around, but usually it just means that we
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* use these trivial conversion functions when the Guest gives us its
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* "physical" addresses:
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*/
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static void *from_guest_phys(unsigned long addr)
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{
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return guest_base + addr;
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}
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static unsigned long to_guest_phys(const void *addr)
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{
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return (addr - guest_base);
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}
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/*L:130
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* Loading the Kernel.
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*
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* We start with couple of simple helper routines. open_or_die() avoids
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* error-checking code cluttering the callers:
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*/
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static int open_or_die(const char *name, int flags)
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{
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int fd = open(name, flags);
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if (fd < 0)
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err(1, "Failed to open %s", name);
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return fd;
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}
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/* map_zeroed_pages() takes a number of pages. */
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static void *map_zeroed_pages(unsigned int num)
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{
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int fd = open_or_die("/dev/zero", O_RDONLY);
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void *addr;
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/*
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* We use a private mapping (ie. if we write to the page, it will be
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* copied). We allocate an extra two pages PROT_NONE to act as guard
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* pages against read/write attempts that exceed allocated space.
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*/
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addr = mmap(NULL, getpagesize() * (num+2),
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PROT_NONE, MAP_PRIVATE, fd, 0);
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if (addr == MAP_FAILED)
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err(1, "Mmapping %u pages of /dev/zero", num);
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if (mprotect(addr + getpagesize(), getpagesize() * num,
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PROT_READ|PROT_WRITE) == -1)
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err(1, "mprotect rw %u pages failed", num);
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/*
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* One neat mmap feature is that you can close the fd, and it
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* stays mapped.
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*/
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close(fd);
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/* Return address after PROT_NONE page */
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return addr + getpagesize();
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}
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/* Get some bytes which won't be mapped into the guest. */
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static unsigned long get_mmio_region(size_t size)
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{
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unsigned long addr = guest_mmio;
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size_t i;
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if (!size)
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return addr;
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/* Size has to be a power of 2 (and multiple of 16) */
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for (i = 1; i < size; i <<= 1);
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guest_mmio += i;
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return addr;
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}
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/*
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* This routine is used to load the kernel or initrd. It tries mmap, but if
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* that fails (Plan 9's kernel file isn't nicely aligned on page boundaries),
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* it falls back to reading the memory in.
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*/
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static void map_at(int fd, void *addr, unsigned long offset, unsigned long len)
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{
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ssize_t r;
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/*
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* We map writable even though for some segments are marked read-only.
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* The kernel really wants to be writable: it patches its own
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* instructions.
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*
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* MAP_PRIVATE means that the page won't be copied until a write is
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* done to it. This allows us to share untouched memory between
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* Guests.
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*/
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if (mmap(addr, len, PROT_READ|PROT_WRITE,
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MAP_FIXED|MAP_PRIVATE, fd, offset) != MAP_FAILED)
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return;
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/* pread does a seek and a read in one shot: saves a few lines. */
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r = pread(fd, addr, len, offset);
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if (r != len)
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err(1, "Reading offset %lu len %lu gave %zi", offset, len, r);
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}
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/*
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* This routine takes an open vmlinux image, which is in ELF, and maps it into
|
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* the Guest memory. ELF = Embedded Linking Format, which is the format used
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* by all modern binaries on Linux including the kernel.
|
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*
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* The ELF headers give *two* addresses: a physical address, and a virtual
|
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* address. We use the physical address; the Guest will map itself to the
|
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* virtual address.
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*
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* We return the starting address.
|
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*/
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static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr)
|
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{
|
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Elf32_Phdr phdr[ehdr->e_phnum];
|
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unsigned int i;
|
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|
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/*
|
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* Sanity checks on the main ELF header: an x86 executable with a
|
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* reasonable number of correctly-sized program headers.
|
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*/
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if (ehdr->e_type != ET_EXEC
|
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|| ehdr->e_machine != EM_386
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|| ehdr->e_phentsize != sizeof(Elf32_Phdr)
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|| ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr))
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errx(1, "Malformed elf header");
|
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|
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/*
|
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* An ELF executable contains an ELF header and a number of "program"
|
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* headers which indicate which parts ("segments") of the program to
|
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* load where.
|
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*/
|
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|
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/* We read in all the program headers at once: */
|
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if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0)
|
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err(1, "Seeking to program headers");
|
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if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr))
|
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err(1, "Reading program headers");
|
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|
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/*
|
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* Try all the headers: there are usually only three. A read-only one,
|
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* a read-write one, and a "note" section which we don't load.
|
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*/
|
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for (i = 0; i < ehdr->e_phnum; i++) {
|
||
/* If this isn't a loadable segment, we ignore it */
|
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if (phdr[i].p_type != PT_LOAD)
|
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continue;
|
||
|
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verbose("Section %i: size %i addr %p\n",
|
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i, phdr[i].p_memsz, (void *)phdr[i].p_paddr);
|
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|
||
/* We map this section of the file at its physical address. */
|
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map_at(elf_fd, from_guest_phys(phdr[i].p_paddr),
|
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phdr[i].p_offset, phdr[i].p_filesz);
|
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}
|
||
|
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/* The entry point is given in the ELF header. */
|
||
return ehdr->e_entry;
|
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}
|
||
|
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/*L:150
|
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* A bzImage, unlike an ELF file, is not meant to be loaded. You're supposed
|
||
* to jump into it and it will unpack itself. We used to have to perform some
|
||
* hairy magic because the unpacking code scared me.
|
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*
|
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* Fortunately, Jeremy Fitzhardinge convinced me it wasn't that hard and wrote
|
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* a small patch to jump over the tricky bits in the Guest, so now we just read
|
||
* the funky header so we know where in the file to load, and away we go!
|
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*/
|
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static unsigned long load_bzimage(int fd)
|
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{
|
||
struct boot_params boot;
|
||
int r;
|
||
/* Modern bzImages get loaded at 1M. */
|
||
void *p = from_guest_phys(0x100000);
|
||
|
||
/*
|
||
* Go back to the start of the file and read the header. It should be
|
||
* a Linux boot header (see Documentation/x86/boot.txt)
|
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*/
|
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lseek(fd, 0, SEEK_SET);
|
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read(fd, &boot, sizeof(boot));
|
||
|
||
/* Inside the setup_hdr, we expect the magic "HdrS" */
|
||
if (memcmp(&boot.hdr.header, "HdrS", 4) != 0)
|
||
errx(1, "This doesn't look like a bzImage to me");
|
||
|
||
/* Skip over the extra sectors of the header. */
|
||
lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET);
|
||
|
||
/* Now read everything into memory. in nice big chunks. */
|
||
while ((r = read(fd, p, 65536)) > 0)
|
||
p += r;
|
||
|
||
/* Finally, code32_start tells us where to enter the kernel. */
|
||
return boot.hdr.code32_start;
|
||
}
|
||
|
||
/*L:140
|
||
* Loading the kernel is easy when it's a "vmlinux", but most kernels
|
||
* come wrapped up in the self-decompressing "bzImage" format. With a little
|
||
* work, we can load those, too.
|
||
*/
|
||
static unsigned long load_kernel(int fd)
|
||
{
|
||
Elf32_Ehdr hdr;
|
||
|
||
/* Read in the first few bytes. */
|
||
if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr))
|
||
err(1, "Reading kernel");
|
||
|
||
/* If it's an ELF file, it starts with "\177ELF" */
|
||
if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0)
|
||
return map_elf(fd, &hdr);
|
||
|
||
/* Otherwise we assume it's a bzImage, and try to load it. */
|
||
return load_bzimage(fd);
|
||
}
|
||
|
||
/*
|
||
* This is a trivial little helper to align pages. Andi Kleen hated it because
|
||
* it calls getpagesize() twice: "it's dumb code."
|
||
*
|
||
* Kernel guys get really het up about optimization, even when it's not
|
||
* necessary. I leave this code as a reaction against that.
|
||
*/
|
||
static inline unsigned long page_align(unsigned long addr)
|
||
{
|
||
/* Add upwards and truncate downwards. */
|
||
return ((addr + getpagesize()-1) & ~(getpagesize()-1));
|
||
}
|
||
|
||
/*L:180
|
||
* An "initial ram disk" is a disk image loaded into memory along with the
|
||
* kernel which the kernel can use to boot from without needing any drivers.
|
||
* Most distributions now use this as standard: the initrd contains the code to
|
||
* load the appropriate driver modules for the current machine.
|
||
*
|
||
* Importantly, James Morris works for RedHat, and Fedora uses initrds for its
|
||
* kernels. He sent me this (and tells me when I break it).
|
||
*/
|
||
static unsigned long load_initrd(const char *name, unsigned long mem)
|
||
{
|
||
int ifd;
|
||
struct stat st;
|
||
unsigned long len;
|
||
|
||
ifd = open_or_die(name, O_RDONLY);
|
||
/* fstat() is needed to get the file size. */
|
||
if (fstat(ifd, &st) < 0)
|
||
err(1, "fstat() on initrd '%s'", name);
|
||
|
||
/*
|
||
* We map the initrd at the top of memory, but mmap wants it to be
|
||
* page-aligned, so we round the size up for that.
|
||
*/
|
||
len = page_align(st.st_size);
|
||
map_at(ifd, from_guest_phys(mem - len), 0, st.st_size);
|
||
/*
|
||
* Once a file is mapped, you can close the file descriptor. It's a
|
||
* little odd, but quite useful.
|
||
*/
|
||
close(ifd);
|
||
verbose("mapped initrd %s size=%lu @ %p\n", name, len, (void*)mem-len);
|
||
|
||
/* We return the initrd size. */
|
||
return len;
|
||
}
|
||
/*:*/
|
||
|
||
/*
|
||
* Simple routine to roll all the commandline arguments together with spaces
|
||
* between them.
|
||
*/
|
||
static void concat(char *dst, char *args[])
|
||
{
|
||
unsigned int i, len = 0;
|
||
|
||
for (i = 0; args[i]; i++) {
|
||
if (i) {
|
||
strcat(dst+len, " ");
|
||
len++;
|
||
}
|
||
strcpy(dst+len, args[i]);
|
||
len += strlen(args[i]);
|
||
}
|
||
/* In case it's empty. */
|
||
dst[len] = '\0';
|
||
}
|
||
|
||
/*L:185
|
||
* This is where we actually tell the kernel to initialize the Guest. We
|
||
* saw the arguments it expects when we looked at initialize() in lguest_user.c:
|
||
* the base of Guest "physical" memory, the top physical page to allow and the
|
||
* entry point for the Guest.
|
||
*/
|
||
static void tell_kernel(unsigned long start)
|
||
{
|
||
unsigned long args[] = { LHREQ_INITIALIZE,
|
||
(unsigned long)guest_base,
|
||
guest_limit / getpagesize(), start,
|
||
(guest_mmio+getpagesize()-1) / getpagesize() };
|
||
verbose("Guest: %p - %p (%#lx, MMIO %#lx)\n",
|
||
guest_base, guest_base + guest_limit,
|
||
guest_limit, guest_mmio);
|
||
lguest_fd = open_or_die("/dev/lguest", O_RDWR);
|
||
if (write(lguest_fd, args, sizeof(args)) < 0)
|
||
err(1, "Writing to /dev/lguest");
|
||
}
|
||
/*:*/
|
||
|
||
/*L:200
|
||
* Device Handling.
|
||
*
|
||
* When the Guest gives us a buffer, it sends an array of addresses and sizes.
|
||
* We need to make sure it's not trying to reach into the Launcher itself, so
|
||
* we have a convenient routine which checks it and exits with an error message
|
||
* if something funny is going on:
|
||
*/
|
||
static void *_check_pointer(unsigned long addr, unsigned int size,
|
||
unsigned int line)
|
||
{
|
||
/*
|
||
* Check if the requested address and size exceeds the allocated memory,
|
||
* or addr + size wraps around.
|
||
*/
|
||
if ((addr + size) > guest_limit || (addr + size) < addr)
|
||
errx(1, "%s:%i: Invalid address %#lx", __FILE__, line, addr);
|
||
/*
|
||
* We return a pointer for the caller's convenience, now we know it's
|
||
* safe to use.
|
||
*/
|
||
return from_guest_phys(addr);
|
||
}
|
||
/* A macro which transparently hands the line number to the real function. */
|
||
#define check_pointer(addr,size) _check_pointer(addr, size, __LINE__)
|
||
|
||
/*
|
||
* Each buffer in the virtqueues is actually a chain of descriptors. This
|
||
* function returns the next descriptor in the chain, or vq->vring.num if we're
|
||
* at the end.
|
||
*/
|
||
static unsigned next_desc(struct vring_desc *desc,
|
||
unsigned int i, unsigned int max)
|
||
{
|
||
unsigned int next;
|
||
|
||
/* If this descriptor says it doesn't chain, we're done. */
|
||
if (!(desc[i].flags & VRING_DESC_F_NEXT))
|
||
return max;
|
||
|
||
/* Check they're not leading us off end of descriptors. */
|
||
next = desc[i].next;
|
||
/* Make sure compiler knows to grab that: we don't want it changing! */
|
||
wmb();
|
||
|
||
if (next >= max)
|
||
errx(1, "Desc next is %u", next);
|
||
|
||
return next;
|
||
}
|
||
|
||
/*
|
||
* This actually sends the interrupt for this virtqueue, if we've used a
|
||
* buffer.
|
||
*/
|
||
static void trigger_irq(struct virtqueue *vq)
|
||
{
|
||
unsigned long buf[] = { LHREQ_IRQ, vq->dev->config.irq_line };
|
||
|
||
/* Don't inform them if nothing used. */
|
||
if (!vq->pending_used)
|
||
return;
|
||
vq->pending_used = 0;
|
||
|
||
/* If they don't want an interrupt, don't send one... */
|
||
if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) {
|
||
return;
|
||
}
|
||
|
||
/*
|
||
* 4.1.4.5.1:
|
||
*
|
||
* If MSI-X capability is disabled, the device MUST set the Queue
|
||
* Interrupt bit in ISR status before sending a virtqueue notification
|
||
* to the driver.
|
||
*/
|
||
vq->dev->mmio->isr = 0x1;
|
||
|
||
/* Send the Guest an interrupt tell them we used something up. */
|
||
if (write(lguest_fd, buf, sizeof(buf)) != 0)
|
||
err(1, "Triggering irq %i", vq->dev->config.irq_line);
|
||
}
|
||
|
||
/*
|
||
* This looks in the virtqueue for the first available buffer, and converts
|
||
* it to an iovec for convenient access. Since descriptors consist of some
|
||
* number of output then some number of input descriptors, it's actually two
|
||
* iovecs, but we pack them into one and note how many of each there were.
|
||
*
|
||
* This function waits if necessary, and returns the descriptor number found.
|
||
*/
|
||
static unsigned wait_for_vq_desc(struct virtqueue *vq,
|
||
struct iovec iov[],
|
||
unsigned int *out_num, unsigned int *in_num)
|
||
{
|
||
unsigned int i, head, max;
|
||
struct vring_desc *desc;
|
||
u16 last_avail = lg_last_avail(vq);
|
||
|
||
/* There's nothing available? */
|
||
while (last_avail == vq->vring.avail->idx) {
|
||
u64 event;
|
||
|
||
/*
|
||
* Since we're about to sleep, now is a good time to tell the
|
||
* Guest about what we've used up to now.
|
||
*/
|
||
trigger_irq(vq);
|
||
|
||
/* OK, now we need to know about added descriptors. */
|
||
vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
|
||
|
||
/*
|
||
* They could have slipped one in as we were doing that: make
|
||
* sure it's written, then check again.
|
||
*/
|
||
mb();
|
||
if (last_avail != vq->vring.avail->idx) {
|
||
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
|
||
break;
|
||
}
|
||
|
||
/* Nothing new? Wait for eventfd to tell us they refilled. */
|
||
if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event))
|
||
errx(1, "Event read failed?");
|
||
|
||
/* We don't need to be notified again. */
|
||
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
|
||
}
|
||
|
||
/* Check it isn't doing very strange things with descriptor numbers. */
|
||
if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
|
||
errx(1, "Guest moved used index from %u to %u",
|
||
last_avail, vq->vring.avail->idx);
|
||
|
||
/*
|
||
* Make sure we read the descriptor number *after* we read the ring
|
||
* update; don't let the cpu or compiler change the order.
|
||
*/
|
||
rmb();
|
||
|
||
/*
|
||
* Grab the next descriptor number they're advertising, and increment
|
||
* the index we've seen.
|
||
*/
|
||
head = vq->vring.avail->ring[last_avail % vq->vring.num];
|
||
lg_last_avail(vq)++;
|
||
|
||
/* If their number is silly, that's a fatal mistake. */
|
||
if (head >= vq->vring.num)
|
||
errx(1, "Guest says index %u is available", head);
|
||
|
||
/* When we start there are none of either input nor output. */
|
||
*out_num = *in_num = 0;
|
||
|
||
max = vq->vring.num;
|
||
desc = vq->vring.desc;
|
||
i = head;
|
||
|
||
/*
|
||
* We have to read the descriptor after we read the descriptor number,
|
||
* but there's a data dependency there so the CPU shouldn't reorder
|
||
* that: no rmb() required.
|
||
*/
|
||
|
||
/*
|
||
* If this is an indirect entry, then this buffer contains a descriptor
|
||
* table which we handle as if it's any normal descriptor chain.
|
||
*/
|
||
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
|
||
if (desc[i].len % sizeof(struct vring_desc))
|
||
errx(1, "Invalid size for indirect buffer table");
|
||
|
||
max = desc[i].len / sizeof(struct vring_desc);
|
||
desc = check_pointer(desc[i].addr, desc[i].len);
|
||
i = 0;
|
||
}
|
||
|
||
do {
|
||
/* Grab the first descriptor, and check it's OK. */
|
||
iov[*out_num + *in_num].iov_len = desc[i].len;
|
||
iov[*out_num + *in_num].iov_base
|
||
= check_pointer(desc[i].addr, desc[i].len);
|
||
/* If this is an input descriptor, increment that count. */
|
||
if (desc[i].flags & VRING_DESC_F_WRITE)
|
||
(*in_num)++;
|
||
else {
|
||
/*
|
||
* If it's an output descriptor, they're all supposed
|
||
* to come before any input descriptors.
|
||
*/
|
||
if (*in_num)
|
||
errx(1, "Descriptor has out after in");
|
||
(*out_num)++;
|
||
}
|
||
|
||
/* If we've got too many, that implies a descriptor loop. */
|
||
if (*out_num + *in_num > max)
|
||
errx(1, "Looped descriptor");
|
||
} while ((i = next_desc(desc, i, max)) != max);
|
||
|
||
return head;
|
||
}
|
||
|
||
/*
|
||
* After we've used one of their buffers, we tell the Guest about it. Sometime
|
||
* later we'll want to send them an interrupt using trigger_irq(); note that
|
||
* wait_for_vq_desc() does that for us if it has to wait.
|
||
*/
|
||
static void add_used(struct virtqueue *vq, unsigned int head, int len)
|
||
{
|
||
struct vring_used_elem *used;
|
||
|
||
/*
|
||
* The virtqueue contains a ring of used buffers. Get a pointer to the
|
||
* next entry in that used ring.
|
||
*/
|
||
used = &vq->vring.used->ring[vq->vring.used->idx % vq->vring.num];
|
||
used->id = head;
|
||
used->len = len;
|
||
/* Make sure buffer is written before we update index. */
|
||
wmb();
|
||
vq->vring.used->idx++;
|
||
vq->pending_used++;
|
||
}
|
||
|
||
/* And here's the combo meal deal. Supersize me! */
|
||
static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len)
|
||
{
|
||
add_used(vq, head, len);
|
||
trigger_irq(vq);
|
||
}
|
||
|
||
/*
|
||
* The Console
|
||
*
|
||
* We associate some data with the console for our exit hack.
|
||
*/
|
||
struct console_abort {
|
||
/* How many times have they hit ^C? */
|
||
int count;
|
||
/* When did they start? */
|
||
struct timeval start;
|
||
};
|
||
|
||
/* This is the routine which handles console input (ie. stdin). */
|
||
static void console_input(struct virtqueue *vq)
|
||
{
|
||
int len;
|
||
unsigned int head, in_num, out_num;
|
||
struct console_abort *abort = vq->dev->priv;
|
||
struct iovec iov[vq->vring.num];
|
||
|
||
/* Make sure there's a descriptor available. */
|
||
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
|
||
if (out_num)
|
||
errx(1, "Output buffers in console in queue?");
|
||
|
||
/* Read into it. This is where we usually wait. */
|
||
len = readv(STDIN_FILENO, iov, in_num);
|
||
if (len <= 0) {
|
||
/* Ran out of input? */
|
||
warnx("Failed to get console input, ignoring console.");
|
||
/*
|
||
* For simplicity, dying threads kill the whole Launcher. So
|
||
* just nap here.
|
||
*/
|
||
for (;;)
|
||
pause();
|
||
}
|
||
|
||
/* Tell the Guest we used a buffer. */
|
||
add_used_and_trigger(vq, head, len);
|
||
|
||
/*
|
||
* Three ^C within one second? Exit.
|
||
*
|
||
* This is such a hack, but works surprisingly well. Each ^C has to
|
||
* be in a buffer by itself, so they can't be too fast. But we check
|
||
* that we get three within about a second, so they can't be too
|
||
* slow.
|
||
*/
|
||
if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) {
|
||
abort->count = 0;
|
||
return;
|
||
}
|
||
|
||
abort->count++;
|
||
if (abort->count == 1)
|
||
gettimeofday(&abort->start, NULL);
|
||
else if (abort->count == 3) {
|
||
struct timeval now;
|
||
gettimeofday(&now, NULL);
|
||
/* Kill all Launcher processes with SIGINT, like normal ^C */
|
||
if (now.tv_sec <= abort->start.tv_sec+1)
|
||
kill(0, SIGINT);
|
||
abort->count = 0;
|
||
}
|
||
}
|
||
|
||
/* This is the routine which handles console output (ie. stdout). */
|
||
static void console_output(struct virtqueue *vq)
|
||
{
|
||
unsigned int head, out, in;
|
||
struct iovec iov[vq->vring.num];
|
||
|
||
/* We usually wait in here, for the Guest to give us something. */
|
||
head = wait_for_vq_desc(vq, iov, &out, &in);
|
||
if (in)
|
||
errx(1, "Input buffers in console output queue?");
|
||
|
||
/* writev can return a partial write, so we loop here. */
|
||
while (!iov_empty(iov, out)) {
|
||
int len = writev(STDOUT_FILENO, iov, out);
|
||
if (len <= 0) {
|
||
warn("Write to stdout gave %i (%d)", len, errno);
|
||
break;
|
||
}
|
||
iov_consume(iov, out, NULL, len);
|
||
}
|
||
|
||
/*
|
||
* We're finished with that buffer: if we're going to sleep,
|
||
* wait_for_vq_desc() will prod the Guest with an interrupt.
|
||
*/
|
||
add_used(vq, head, 0);
|
||
}
|
||
|
||
/*
|
||
* The Network
|
||
*
|
||
* Handling output for network is also simple: we get all the output buffers
|
||
* and write them to /dev/net/tun.
|
||
*/
|
||
struct net_info {
|
||
int tunfd;
|
||
};
|
||
|
||
static void net_output(struct virtqueue *vq)
|
||
{
|
||
struct net_info *net_info = vq->dev->priv;
|
||
unsigned int head, out, in;
|
||
struct iovec iov[vq->vring.num];
|
||
|
||
/* We usually wait in here for the Guest to give us a packet. */
|
||
head = wait_for_vq_desc(vq, iov, &out, &in);
|
||
if (in)
|
||
errx(1, "Input buffers in net output queue?");
|
||
/*
|
||
* Send the whole thing through to /dev/net/tun. It expects the exact
|
||
* same format: what a coincidence!
|
||
*/
|
||
if (writev(net_info->tunfd, iov, out) < 0)
|
||
warnx("Write to tun failed (%d)?", errno);
|
||
|
||
/*
|
||
* Done with that one; wait_for_vq_desc() will send the interrupt if
|
||
* all packets are processed.
|
||
*/
|
||
add_used(vq, head, 0);
|
||
}
|
||
|
||
/*
|
||
* Handling network input is a bit trickier, because I've tried to optimize it.
|
||
*
|
||
* First we have a helper routine which tells is if from this file descriptor
|
||
* (ie. the /dev/net/tun device) will block:
|
||
*/
|
||
static bool will_block(int fd)
|
||
{
|
||
fd_set fdset;
|
||
struct timeval zero = { 0, 0 };
|
||
FD_ZERO(&fdset);
|
||
FD_SET(fd, &fdset);
|
||
return select(fd+1, &fdset, NULL, NULL, &zero) != 1;
|
||
}
|
||
|
||
/*
|
||
* This handles packets coming in from the tun device to our Guest. Like all
|
||
* service routines, it gets called again as soon as it returns, so you don't
|
||
* see a while(1) loop here.
|
||
*/
|
||
static void net_input(struct virtqueue *vq)
|
||
{
|
||
int len;
|
||
unsigned int head, out, in;
|
||
struct iovec iov[vq->vring.num];
|
||
struct net_info *net_info = vq->dev->priv;
|
||
|
||
/*
|
||
* Get a descriptor to write an incoming packet into. This will also
|
||
* send an interrupt if they're out of descriptors.
|
||
*/
|
||
head = wait_for_vq_desc(vq, iov, &out, &in);
|
||
if (out)
|
||
errx(1, "Output buffers in net input queue?");
|
||
|
||
/*
|
||
* If it looks like we'll block reading from the tun device, send them
|
||
* an interrupt.
|
||
*/
|
||
if (vq->pending_used && will_block(net_info->tunfd))
|
||
trigger_irq(vq);
|
||
|
||
/*
|
||
* Read in the packet. This is where we normally wait (when there's no
|
||
* incoming network traffic).
|
||
*/
|
||
len = readv(net_info->tunfd, iov, in);
|
||
if (len <= 0)
|
||
warn("Failed to read from tun (%d).", errno);
|
||
|
||
/*
|
||
* Mark that packet buffer as used, but don't interrupt here. We want
|
||
* to wait until we've done as much work as we can.
|
||
*/
|
||
add_used(vq, head, len);
|
||
}
|
||
/*:*/
|
||
|
||
/* This is the helper to create threads: run the service routine in a loop. */
|
||
static int do_thread(void *_vq)
|
||
{
|
||
struct virtqueue *vq = _vq;
|
||
|
||
for (;;)
|
||
vq->service(vq);
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
* When a child dies, we kill our entire process group with SIGTERM. This
|
||
* also has the side effect that the shell restores the console for us!
|
||
*/
|
||
static void kill_launcher(int signal)
|
||
{
|
||
kill(0, SIGTERM);
|
||
}
|
||
|
||
static void reset_vq_pci_config(struct virtqueue *vq)
|
||
{
|
||
vq->pci_config.queue_size = VIRTQUEUE_NUM;
|
||
vq->pci_config.queue_enable = 0;
|
||
}
|
||
|
||
static void reset_device(struct device *dev)
|
||
{
|
||
struct virtqueue *vq;
|
||
|
||
verbose("Resetting device %s\n", dev->name);
|
||
|
||
/* Clear any features they've acked. */
|
||
dev->features_accepted = 0;
|
||
|
||
/* We're going to be explicitly killing threads, so ignore them. */
|
||
signal(SIGCHLD, SIG_IGN);
|
||
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST present a 0 in queue_enable on reset.
|
||
*
|
||
* This means we set it here, and reset the saved ones in every vq.
|
||
*/
|
||
dev->mmio->cfg.queue_enable = 0;
|
||
|
||
/* Get rid of the virtqueue threads */
|
||
for (vq = dev->vq; vq; vq = vq->next) {
|
||
vq->last_avail_idx = 0;
|
||
reset_vq_pci_config(vq);
|
||
if (vq->thread != (pid_t)-1) {
|
||
kill(vq->thread, SIGTERM);
|
||
waitpid(vq->thread, NULL, 0);
|
||
vq->thread = (pid_t)-1;
|
||
}
|
||
}
|
||
dev->running = false;
|
||
|
||
/* Now we care if threads die. */
|
||
signal(SIGCHLD, (void *)kill_launcher);
|
||
}
|
||
|
||
static void cleanup_devices(void)
|
||
{
|
||
unsigned int i;
|
||
|
||
for (i = 1; i < MAX_PCI_DEVICES; i++) {
|
||
struct device *d = devices.pci[i];
|
||
if (!d)
|
||
continue;
|
||
reset_device(d);
|
||
}
|
||
|
||
/* If we saved off the original terminal settings, restore them now. */
|
||
if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
|
||
tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
|
||
}
|
||
|
||
/*L:217
|
||
* We do PCI. This is mainly done to let us test the kernel virtio PCI
|
||
* code.
|
||
*/
|
||
|
||
/* Linux expects a PCI host bridge: ours is a dummy, and first on the bus. */
|
||
static struct device pci_host_bridge;
|
||
|
||
static void init_pci_host_bridge(void)
|
||
{
|
||
pci_host_bridge.name = "PCI Host Bridge";
|
||
pci_host_bridge.config.class = 0x06; /* bridge */
|
||
pci_host_bridge.config.subclass = 0; /* host bridge */
|
||
devices.pci[0] = &pci_host_bridge;
|
||
}
|
||
|
||
/* The IO ports used to read the PCI config space. */
|
||
#define PCI_CONFIG_ADDR 0xCF8
|
||
#define PCI_CONFIG_DATA 0xCFC
|
||
|
||
/*
|
||
* Not really portable, but does help readability: this is what the Guest
|
||
* writes to the PCI_CONFIG_ADDR IO port.
|
||
*/
|
||
union pci_config_addr {
|
||
struct {
|
||
unsigned mbz: 2;
|
||
unsigned offset: 6;
|
||
unsigned funcnum: 3;
|
||
unsigned devnum: 5;
|
||
unsigned busnum: 8;
|
||
unsigned reserved: 7;
|
||
unsigned enabled : 1;
|
||
} bits;
|
||
u32 val;
|
||
};
|
||
|
||
/*
|
||
* We cache what they wrote to the address port, so we know what they're
|
||
* talking about when they access the data port.
|
||
*/
|
||
static union pci_config_addr pci_config_addr;
|
||
|
||
static struct device *find_pci_device(unsigned int index)
|
||
{
|
||
return devices.pci[index];
|
||
}
|
||
|
||
/* PCI can do 1, 2 and 4 byte reads; we handle that here. */
|
||
static void ioread(u16 off, u32 v, u32 mask, u32 *val)
|
||
{
|
||
assert(off < 4);
|
||
assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
|
||
*val = (v >> (off * 8)) & mask;
|
||
}
|
||
|
||
/* PCI can do 1, 2 and 4 byte writes; we handle that here. */
|
||
static void iowrite(u16 off, u32 v, u32 mask, u32 *dst)
|
||
{
|
||
assert(off < 4);
|
||
assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
|
||
*dst &= ~(mask << (off * 8));
|
||
*dst |= (v & mask) << (off * 8);
|
||
}
|
||
|
||
/*
|
||
* Where PCI_CONFIG_DATA accesses depends on the previous write to
|
||
* PCI_CONFIG_ADDR.
|
||
*/
|
||
static struct device *dev_and_reg(u32 *reg)
|
||
{
|
||
if (!pci_config_addr.bits.enabled)
|
||
return NULL;
|
||
|
||
if (pci_config_addr.bits.funcnum != 0)
|
||
return NULL;
|
||
|
||
if (pci_config_addr.bits.busnum != 0)
|
||
return NULL;
|
||
|
||
if (pci_config_addr.bits.offset * 4 >= sizeof(struct pci_config))
|
||
return NULL;
|
||
|
||
*reg = pci_config_addr.bits.offset;
|
||
return find_pci_device(pci_config_addr.bits.devnum);
|
||
}
|
||
|
||
/*
|
||
* We can get invalid combinations of values while they're writing, so we
|
||
* only fault if they try to write with some invalid bar/offset/length.
|
||
*/
|
||
static bool valid_bar_access(struct device *d,
|
||
struct virtio_pci_cfg_cap *cfg_access)
|
||
{
|
||
/* We only have 1 bar (BAR0) */
|
||
if (cfg_access->cap.bar != 0)
|
||
return false;
|
||
|
||
/* Check it's within BAR0. */
|
||
if (cfg_access->cap.offset >= d->mmio_size
|
||
|| cfg_access->cap.offset + cfg_access->cap.length > d->mmio_size)
|
||
return false;
|
||
|
||
/* Check length is 1, 2 or 4. */
|
||
if (cfg_access->cap.length != 1
|
||
&& cfg_access->cap.length != 2
|
||
&& cfg_access->cap.length != 4)
|
||
return false;
|
||
|
||
/*
|
||
* 4.1.4.7.2:
|
||
*
|
||
* The driver MUST NOT write a cap.offset which is not a multiple of
|
||
* cap.length (ie. all accesses MUST be aligned).
|
||
*/
|
||
if (cfg_access->cap.offset % cfg_access->cap.length != 0)
|
||
return false;
|
||
|
||
/* Return pointer into word in BAR0. */
|
||
return true;
|
||
}
|
||
|
||
/* Is this accessing the PCI config address port?. */
|
||
static bool is_pci_addr_port(u16 port)
|
||
{
|
||
return port >= PCI_CONFIG_ADDR && port < PCI_CONFIG_ADDR + 4;
|
||
}
|
||
|
||
static bool pci_addr_iowrite(u16 port, u32 mask, u32 val)
|
||
{
|
||
iowrite(port - PCI_CONFIG_ADDR, val, mask,
|
||
&pci_config_addr.val);
|
||
verbose("PCI%s: %#x/%x: bus %u dev %u func %u reg %u\n",
|
||
pci_config_addr.bits.enabled ? "" : " DISABLED",
|
||
val, mask,
|
||
pci_config_addr.bits.busnum,
|
||
pci_config_addr.bits.devnum,
|
||
pci_config_addr.bits.funcnum,
|
||
pci_config_addr.bits.offset);
|
||
return true;
|
||
}
|
||
|
||
static void pci_addr_ioread(u16 port, u32 mask, u32 *val)
|
||
{
|
||
ioread(port - PCI_CONFIG_ADDR, pci_config_addr.val, mask, val);
|
||
}
|
||
|
||
/* Is this accessing the PCI config data port?. */
|
||
static bool is_pci_data_port(u16 port)
|
||
{
|
||
return port >= PCI_CONFIG_DATA && port < PCI_CONFIG_DATA + 4;
|
||
}
|
||
|
||
static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask);
|
||
|
||
static bool pci_data_iowrite(u16 port, u32 mask, u32 val)
|
||
{
|
||
u32 reg, portoff;
|
||
struct device *d = dev_and_reg(®);
|
||
|
||
/* Complain if they don't belong to a device. */
|
||
if (!d)
|
||
return false;
|
||
|
||
/* They can do 1 byte writes, etc. */
|
||
portoff = port - PCI_CONFIG_DATA;
|
||
|
||
/*
|
||
* PCI uses a weird way to determine the BAR size: the OS
|
||
* writes all 1's, and sees which ones stick.
|
||
*/
|
||
if (&d->config_words[reg] == &d->config.bar[0]) {
|
||
int i;
|
||
|
||
iowrite(portoff, val, mask, &d->config.bar[0]);
|
||
for (i = 0; (1 << i) < d->mmio_size; i++)
|
||
d->config.bar[0] &= ~(1 << i);
|
||
return true;
|
||
} else if ((&d->config_words[reg] > &d->config.bar[0]
|
||
&& &d->config_words[reg] <= &d->config.bar[6])
|
||
|| &d->config_words[reg] == &d->config.expansion_rom_addr) {
|
||
/* Allow writing to any other BAR, or expansion ROM */
|
||
iowrite(portoff, val, mask, &d->config_words[reg]);
|
||
return true;
|
||
/* We let them overide latency timer and cacheline size */
|
||
} else if (&d->config_words[reg] == (void *)&d->config.cacheline_size) {
|
||
/* Only let them change the first two fields. */
|
||
if (mask == 0xFFFFFFFF)
|
||
mask = 0xFFFF;
|
||
iowrite(portoff, val, mask, &d->config_words[reg]);
|
||
return true;
|
||
} else if (&d->config_words[reg] == (void *)&d->config.command
|
||
&& mask == 0xFFFF) {
|
||
/* Ignore command writes. */
|
||
return true;
|
||
} else if (&d->config_words[reg]
|
||
== (void *)&d->config.cfg_access.cap.bar
|
||
|| &d->config_words[reg]
|
||
== &d->config.cfg_access.cap.length
|
||
|| &d->config_words[reg]
|
||
== &d->config.cfg_access.cap.offset) {
|
||
|
||
/*
|
||
* The VIRTIO_PCI_CAP_PCI_CFG capability
|
||
* provides a backdoor to access the MMIO
|
||
* regions without mapping them. Weird, but
|
||
* useful.
|
||
*/
|
||
iowrite(portoff, val, mask, &d->config_words[reg]);
|
||
return true;
|
||
} else if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
|
||
u32 write_mask;
|
||
|
||
/*
|
||
* 4.1.4.7.1:
|
||
*
|
||
* Upon detecting driver write access to pci_cfg_data, the
|
||
* device MUST execute a write access at offset cap.offset at
|
||
* BAR selected by cap.bar using the first cap.length bytes
|
||
* from pci_cfg_data.
|
||
*/
|
||
|
||
/* Must be bar 0 */
|
||
if (!valid_bar_access(d, &d->config.cfg_access))
|
||
return false;
|
||
|
||
iowrite(portoff, val, mask, &d->config.cfg_access.pci_cfg_data);
|
||
|
||
/*
|
||
* Now emulate a write. The mask we use is set by
|
||
* len, *not* this write!
|
||
*/
|
||
write_mask = (1ULL<<(8*d->config.cfg_access.cap.length)) - 1;
|
||
verbose("Window writing %#x/%#x to bar %u, offset %u len %u\n",
|
||
d->config.cfg_access.pci_cfg_data, write_mask,
|
||
d->config.cfg_access.cap.bar,
|
||
d->config.cfg_access.cap.offset,
|
||
d->config.cfg_access.cap.length);
|
||
|
||
emulate_mmio_write(d, d->config.cfg_access.cap.offset,
|
||
d->config.cfg_access.pci_cfg_data,
|
||
write_mask);
|
||
return true;
|
||
}
|
||
|
||
/*
|
||
* 4.1.4.1:
|
||
*
|
||
* The driver MUST NOT write into any field of the capability
|
||
* structure, with the exception of those with cap_type
|
||
* VIRTIO_PCI_CAP_PCI_CFG...
|
||
*/
|
||
return false;
|
||
}
|
||
|
||
static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask);
|
||
|
||
static void pci_data_ioread(u16 port, u32 mask, u32 *val)
|
||
{
|
||
u32 reg;
|
||
struct device *d = dev_and_reg(®);
|
||
|
||
if (!d)
|
||
return;
|
||
|
||
/* Read through the PCI MMIO access window is special */
|
||
if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
|
||
u32 read_mask;
|
||
|
||
/*
|
||
* 4.1.4.7.1:
|
||
*
|
||
* Upon detecting driver read access to pci_cfg_data, the
|
||
* device MUST execute a read access of length cap.length at
|
||
* offset cap.offset at BAR selected by cap.bar and store the
|
||
* first cap.length bytes in pci_cfg_data.
|
||
*/
|
||
/* Must be bar 0 */
|
||
if (!valid_bar_access(d, &d->config.cfg_access))
|
||
errx(1, "Invalid cfg_access to bar%u, offset %u len %u",
|
||
d->config.cfg_access.cap.bar,
|
||
d->config.cfg_access.cap.offset,
|
||
d->config.cfg_access.cap.length);
|
||
|
||
/*
|
||
* Read into the window. The mask we use is set by
|
||
* len, *not* this read!
|
||
*/
|
||
read_mask = (1ULL<<(8*d->config.cfg_access.cap.length))-1;
|
||
d->config.cfg_access.pci_cfg_data
|
||
= emulate_mmio_read(d,
|
||
d->config.cfg_access.cap.offset,
|
||
read_mask);
|
||
verbose("Window read %#x/%#x from bar %u, offset %u len %u\n",
|
||
d->config.cfg_access.pci_cfg_data, read_mask,
|
||
d->config.cfg_access.cap.bar,
|
||
d->config.cfg_access.cap.offset,
|
||
d->config.cfg_access.cap.length);
|
||
}
|
||
ioread(port - PCI_CONFIG_DATA, d->config_words[reg], mask, val);
|
||
}
|
||
|
||
/*L:216
|
||
* This is where we emulate a handful of Guest instructions. It's ugly
|
||
* and we used to do it in the kernel but it grew over time.
|
||
*/
|
||
|
||
/*
|
||
* We use the ptrace syscall's pt_regs struct to talk about registers
|
||
* to lguest: these macros convert the names to the offsets.
|
||
*/
|
||
#define getreg(name) getreg_off(offsetof(struct user_regs_struct, name))
|
||
#define setreg(name, val) \
|
||
setreg_off(offsetof(struct user_regs_struct, name), (val))
|
||
|
||
static u32 getreg_off(size_t offset)
|
||
{
|
||
u32 r;
|
||
unsigned long args[] = { LHREQ_GETREG, offset };
|
||
|
||
if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
|
||
err(1, "Getting register %u", offset);
|
||
if (pread(lguest_fd, &r, sizeof(r), cpu_id) != sizeof(r))
|
||
err(1, "Reading register %u", offset);
|
||
|
||
return r;
|
||
}
|
||
|
||
static void setreg_off(size_t offset, u32 val)
|
||
{
|
||
unsigned long args[] = { LHREQ_SETREG, offset, val };
|
||
|
||
if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
|
||
err(1, "Setting register %u", offset);
|
||
}
|
||
|
||
/* Get register by instruction encoding */
|
||
static u32 getreg_num(unsigned regnum, u32 mask)
|
||
{
|
||
/* 8 bit ops use regnums 4-7 for high parts of word */
|
||
if (mask == 0xFF && (regnum & 0x4))
|
||
return getreg_num(regnum & 0x3, 0xFFFF) >> 8;
|
||
|
||
switch (regnum) {
|
||
case 0: return getreg(eax) & mask;
|
||
case 1: return getreg(ecx) & mask;
|
||
case 2: return getreg(edx) & mask;
|
||
case 3: return getreg(ebx) & mask;
|
||
case 4: return getreg(esp) & mask;
|
||
case 5: return getreg(ebp) & mask;
|
||
case 6: return getreg(esi) & mask;
|
||
case 7: return getreg(edi) & mask;
|
||
}
|
||
abort();
|
||
}
|
||
|
||
/* Set register by instruction encoding */
|
||
static void setreg_num(unsigned regnum, u32 val, u32 mask)
|
||
{
|
||
/* Don't try to set bits out of range */
|
||
assert(~(val & ~mask));
|
||
|
||
/* 8 bit ops use regnums 4-7 for high parts of word */
|
||
if (mask == 0xFF && (regnum & 0x4)) {
|
||
/* Construct the 16 bits we want. */
|
||
val = (val << 8) | getreg_num(regnum & 0x3, 0xFF);
|
||
setreg_num(regnum & 0x3, val, 0xFFFF);
|
||
return;
|
||
}
|
||
|
||
switch (regnum) {
|
||
case 0: setreg(eax, val | (getreg(eax) & ~mask)); return;
|
||
case 1: setreg(ecx, val | (getreg(ecx) & ~mask)); return;
|
||
case 2: setreg(edx, val | (getreg(edx) & ~mask)); return;
|
||
case 3: setreg(ebx, val | (getreg(ebx) & ~mask)); return;
|
||
case 4: setreg(esp, val | (getreg(esp) & ~mask)); return;
|
||
case 5: setreg(ebp, val | (getreg(ebp) & ~mask)); return;
|
||
case 6: setreg(esi, val | (getreg(esi) & ~mask)); return;
|
||
case 7: setreg(edi, val | (getreg(edi) & ~mask)); return;
|
||
}
|
||
abort();
|
||
}
|
||
|
||
/* Get bytes of displacement appended to instruction, from r/m encoding */
|
||
static u32 insn_displacement_len(u8 mod_reg_rm)
|
||
{
|
||
/* Switch on the mod bits */
|
||
switch (mod_reg_rm >> 6) {
|
||
case 0:
|
||
/* If mod == 0, and r/m == 101, 16-bit displacement follows */
|
||
if ((mod_reg_rm & 0x7) == 0x5)
|
||
return 2;
|
||
/* Normally, mod == 0 means no literal displacement */
|
||
return 0;
|
||
case 1:
|
||
/* One byte displacement */
|
||
return 1;
|
||
case 2:
|
||
/* Four byte displacement */
|
||
return 4;
|
||
case 3:
|
||
/* Register mode */
|
||
return 0;
|
||
}
|
||
abort();
|
||
}
|
||
|
||
static void emulate_insn(const u8 insn[])
|
||
{
|
||
unsigned long args[] = { LHREQ_TRAP, 13 };
|
||
unsigned int insnlen = 0, in = 0, small_operand = 0, byte_access;
|
||
unsigned int eax, port, mask;
|
||
/*
|
||
* Default is to return all-ones on IO port reads, which traditionally
|
||
* means "there's nothing there".
|
||
*/
|
||
u32 val = 0xFFFFFFFF;
|
||
|
||
/*
|
||
* This must be the Guest kernel trying to do something, not userspace!
|
||
* The bottom two bits of the CS segment register are the privilege
|
||
* level.
|
||
*/
|
||
if ((getreg(xcs) & 3) != 0x1)
|
||
goto no_emulate;
|
||
|
||
/* Decoding x86 instructions is icky. */
|
||
|
||
/*
|
||
* Around 2.6.33, the kernel started using an emulation for the
|
||
* cmpxchg8b instruction in early boot on many configurations. This
|
||
* code isn't paravirtualized, and it tries to disable interrupts.
|
||
* Ignore it, which will Mostly Work.
|
||
*/
|
||
if (insn[insnlen] == 0xfa) {
|
||
/* "cli", or Clear Interrupt Enable instruction. Skip it. */
|
||
insnlen = 1;
|
||
goto skip_insn;
|
||
}
|
||
|
||
/*
|
||
* 0x66 is an "operand prefix". It means a 16, not 32 bit in/out.
|
||
*/
|
||
if (insn[insnlen] == 0x66) {
|
||
small_operand = 1;
|
||
/* The instruction is 1 byte so far, read the next byte. */
|
||
insnlen = 1;
|
||
}
|
||
|
||
/* If the lower bit isn't set, it's a single byte access */
|
||
byte_access = !(insn[insnlen] & 1);
|
||
|
||
/*
|
||
* Now we can ignore the lower bit and decode the 4 opcodes
|
||
* we need to emulate.
|
||
*/
|
||
switch (insn[insnlen] & 0xFE) {
|
||
case 0xE4: /* in <next byte>,%al */
|
||
port = insn[insnlen+1];
|
||
insnlen += 2;
|
||
in = 1;
|
||
break;
|
||
case 0xEC: /* in (%dx),%al */
|
||
port = getreg(edx) & 0xFFFF;
|
||
insnlen += 1;
|
||
in = 1;
|
||
break;
|
||
case 0xE6: /* out %al,<next byte> */
|
||
port = insn[insnlen+1];
|
||
insnlen += 2;
|
||
break;
|
||
case 0xEE: /* out %al,(%dx) */
|
||
port = getreg(edx) & 0xFFFF;
|
||
insnlen += 1;
|
||
break;
|
||
default:
|
||
/* OK, we don't know what this is, can't emulate. */
|
||
goto no_emulate;
|
||
}
|
||
|
||
/* Set a mask of the 1, 2 or 4 bytes, depending on size of IO */
|
||
if (byte_access)
|
||
mask = 0xFF;
|
||
else if (small_operand)
|
||
mask = 0xFFFF;
|
||
else
|
||
mask = 0xFFFFFFFF;
|
||
|
||
/*
|
||
* If it was an "IN" instruction, they expect the result to be read
|
||
* into %eax, so we change %eax.
|
||
*/
|
||
eax = getreg(eax);
|
||
|
||
if (in) {
|
||
/* This is the PS/2 keyboard status; 1 means ready for output */
|
||
if (port == 0x64)
|
||
val = 1;
|
||
else if (is_pci_addr_port(port))
|
||
pci_addr_ioread(port, mask, &val);
|
||
else if (is_pci_data_port(port))
|
||
pci_data_ioread(port, mask, &val);
|
||
|
||
/* Clear the bits we're about to read */
|
||
eax &= ~mask;
|
||
/* Copy bits in from val. */
|
||
eax |= val & mask;
|
||
/* Now update the register. */
|
||
setreg(eax, eax);
|
||
} else {
|
||
if (is_pci_addr_port(port)) {
|
||
if (!pci_addr_iowrite(port, mask, eax))
|
||
goto bad_io;
|
||
} else if (is_pci_data_port(port)) {
|
||
if (!pci_data_iowrite(port, mask, eax))
|
||
goto bad_io;
|
||
}
|
||
/* There are many other ports, eg. CMOS clock, serial
|
||
* and parallel ports, so we ignore them all. */
|
||
}
|
||
|
||
verbose("IO %s of %x to %u: %#08x\n",
|
||
in ? "IN" : "OUT", mask, port, eax);
|
||
skip_insn:
|
||
/* Finally, we've "done" the instruction, so move past it. */
|
||
setreg(eip, getreg(eip) + insnlen);
|
||
return;
|
||
|
||
bad_io:
|
||
warnx("Attempt to %s port %u (%#x mask)",
|
||
in ? "read from" : "write to", port, mask);
|
||
|
||
no_emulate:
|
||
/* Inject trap into Guest. */
|
||
if (write(lguest_fd, args, sizeof(args)) < 0)
|
||
err(1, "Reinjecting trap 13 for fault at %#x", getreg(eip));
|
||
}
|
||
|
||
static struct device *find_mmio_region(unsigned long paddr, u32 *off)
|
||
{
|
||
unsigned int i;
|
||
|
||
for (i = 1; i < MAX_PCI_DEVICES; i++) {
|
||
struct device *d = devices.pci[i];
|
||
|
||
if (!d)
|
||
continue;
|
||
if (paddr < d->mmio_addr)
|
||
continue;
|
||
if (paddr >= d->mmio_addr + d->mmio_size)
|
||
continue;
|
||
*off = paddr - d->mmio_addr;
|
||
return d;
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
/* FIXME: Use vq array. */
|
||
static struct virtqueue *vq_by_num(struct device *d, u32 num)
|
||
{
|
||
struct virtqueue *vq = d->vq;
|
||
|
||
while (num-- && vq)
|
||
vq = vq->next;
|
||
|
||
return vq;
|
||
}
|
||
|
||
static void save_vq_config(const struct virtio_pci_common_cfg *cfg,
|
||
struct virtqueue *vq)
|
||
{
|
||
vq->pci_config = *cfg;
|
||
}
|
||
|
||
static void restore_vq_config(struct virtio_pci_common_cfg *cfg,
|
||
struct virtqueue *vq)
|
||
{
|
||
/* Only restore the per-vq part */
|
||
size_t off = offsetof(struct virtio_pci_common_cfg, queue_size);
|
||
|
||
memcpy((void *)cfg + off, (void *)&vq->pci_config + off,
|
||
sizeof(*cfg) - off);
|
||
}
|
||
|
||
/*
|
||
* When they enable the virtqueue, we check that their setup is valid.
|
||
*/
|
||
static void enable_virtqueue(struct device *d, struct virtqueue *vq)
|
||
{
|
||
/*
|
||
* Create stack for thread. Since the stack grows upwards, we point
|
||
* the stack pointer to the end of this region.
|
||
*/
|
||
char *stack = malloc(32768);
|
||
|
||
/* Because lguest is 32 bit, all the descriptor high bits must be 0 */
|
||
if (vq->pci_config.queue_desc_hi
|
||
|| vq->pci_config.queue_avail_hi
|
||
|| vq->pci_config.queue_used_hi)
|
||
errx(1, "%s: invalid 64-bit queue address", d->name);
|
||
|
||
/* Initialize the virtqueue and check they're all in range. */
|
||
vq->vring.num = vq->pci_config.queue_size;
|
||
vq->vring.desc = check_pointer(vq->pci_config.queue_desc_lo,
|
||
sizeof(*vq->vring.desc) * vq->vring.num);
|
||
vq->vring.avail = check_pointer(vq->pci_config.queue_avail_lo,
|
||
sizeof(*vq->vring.avail)
|
||
+ (sizeof(vq->vring.avail->ring[0])
|
||
* vq->vring.num));
|
||
vq->vring.used = check_pointer(vq->pci_config.queue_used_lo,
|
||
sizeof(*vq->vring.used)
|
||
+ (sizeof(vq->vring.used->ring[0])
|
||
* vq->vring.num));
|
||
|
||
|
||
/* Create a zero-initialized eventfd. */
|
||
vq->eventfd = eventfd(0, 0);
|
||
if (vq->eventfd < 0)
|
||
err(1, "Creating eventfd");
|
||
|
||
/*
|
||
* CLONE_VM: because it has to access the Guest memory, and SIGCHLD so
|
||
* we get a signal if it dies.
|
||
*/
|
||
vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq);
|
||
if (vq->thread == (pid_t)-1)
|
||
err(1, "Creating clone");
|
||
}
|
||
|
||
static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
|
||
{
|
||
struct virtqueue *vq;
|
||
|
||
switch (off) {
|
||
case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST present the feature bits it is offering in
|
||
* device_feature, starting at bit device_feature_select ∗ 32
|
||
* for any device_feature_select written by the driver
|
||
*/
|
||
if (val == 0)
|
||
d->mmio->cfg.device_feature = d->features;
|
||
else if (val == 1)
|
||
d->mmio->cfg.device_feature = (d->features >> 32);
|
||
else
|
||
d->mmio->cfg.device_feature = 0;
|
||
goto write_through32;
|
||
case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
|
||
if (val > 1)
|
||
errx(1, "%s: Unexpected driver select %u",
|
||
d->name, val);
|
||
goto write_through32;
|
||
case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
|
||
if (d->mmio->cfg.guest_feature_select == 0) {
|
||
d->features_accepted &= ~((u64)0xFFFFFFFF);
|
||
d->features_accepted |= val;
|
||
} else {
|
||
assert(d->mmio->cfg.guest_feature_select == 1);
|
||
d->features_accepted &= 0xFFFFFFFF;
|
||
d->features_accepted |= ((u64)val) << 32;
|
||
}
|
||
if (d->features_accepted & ~d->features)
|
||
errx(1, "%s: over-accepted features %#llx of %#llx",
|
||
d->name, d->features_accepted, d->features);
|
||
goto write_through32;
|
||
case offsetof(struct virtio_pci_mmio, cfg.device_status):
|
||
verbose("%s: device status -> %#x\n", d->name, val);
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST reset when 0 is written to device_status,
|
||
* and present a 0 in device_status once that is done.
|
||
*/
|
||
if (val == 0)
|
||
reset_device(d);
|
||
goto write_through8;
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_select):
|
||
vq = vq_by_num(d, val);
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST present a 0 in queue_size if the virtqueue
|
||
* corresponding to the current queue_select is unavailable.
|
||
*/
|
||
if (!vq) {
|
||
d->mmio->cfg.queue_size = 0;
|
||
goto write_through16;
|
||
}
|
||
/* Save registers for old vq, if it was a valid vq */
|
||
if (d->mmio->cfg.queue_size)
|
||
save_vq_config(&d->mmio->cfg,
|
||
vq_by_num(d, d->mmio->cfg.queue_select));
|
||
/* Restore the registers for the queue they asked for */
|
||
restore_vq_config(&d->mmio->cfg, vq);
|
||
goto write_through16;
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_size):
|
||
/*
|
||
* 4.1.4.3.2:
|
||
*
|
||
* The driver MUST NOT write a value which is not a power of 2
|
||
* to queue_size.
|
||
*/
|
||
if (val & (val-1))
|
||
errx(1, "%s: invalid queue size %u\n", d->name, val);
|
||
if (d->mmio->cfg.queue_enable)
|
||
errx(1, "%s: changing queue size on live device",
|
||
d->name);
|
||
goto write_through16;
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_msix_vector):
|
||
errx(1, "%s: attempt to set MSIX vector to %u",
|
||
d->name, val);
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_enable):
|
||
/*
|
||
* 4.1.4.3.2:
|
||
*
|
||
* The driver MUST NOT write a 0 to queue_enable.
|
||
*/
|
||
if (val != 1)
|
||
errx(1, "%s: setting queue_enable to %u", d->name, val);
|
||
d->mmio->cfg.queue_enable = val;
|
||
save_vq_config(&d->mmio->cfg,
|
||
vq_by_num(d, d->mmio->cfg.queue_select));
|
||
/*
|
||
* 4.1.4.3.2:
|
||
*
|
||
* The driver MUST configure the other virtqueue fields before
|
||
* enabling the virtqueue with queue_enable.
|
||
*/
|
||
enable_virtqueue(d, vq_by_num(d, d->mmio->cfg.queue_select));
|
||
goto write_through16;
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_notify_off):
|
||
errx(1, "%s: attempt to write to queue_notify_off", d->name);
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_desc_lo):
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_desc_hi):
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_avail_lo):
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_avail_hi):
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_used_lo):
|
||
case offsetof(struct virtio_pci_mmio, cfg.queue_used_hi):
|
||
/*
|
||
* 4.1.4.3.2:
|
||
*
|
||
* The driver MUST configure the other virtqueue fields before
|
||
* enabling the virtqueue with queue_enable.
|
||
*/
|
||
if (d->mmio->cfg.queue_enable)
|
||
errx(1, "%s: changing queue on live device",
|
||
d->name);
|
||
goto write_through32;
|
||
case offsetof(struct virtio_pci_mmio, notify):
|
||
vq = vq_by_num(d, val);
|
||
if (!vq)
|
||
errx(1, "Invalid vq notification on %u", val);
|
||
/* Notify the process handling this vq by adding 1 to eventfd */
|
||
write(vq->eventfd, "\1\0\0\0\0\0\0\0", 8);
|
||
goto write_through16;
|
||
case offsetof(struct virtio_pci_mmio, isr):
|
||
errx(1, "%s: Unexpected write to isr", d->name);
|
||
/* Weird corner case: write to emerg_wr of console */
|
||
case sizeof(struct virtio_pci_mmio)
|
||
+ offsetof(struct virtio_console_config, emerg_wr):
|
||
if (strcmp(d->name, "console") == 0) {
|
||
char c = val;
|
||
write(STDOUT_FILENO, &c, 1);
|
||
goto write_through32;
|
||
}
|
||
/* Fall through... */
|
||
default:
|
||
/*
|
||
* 4.1.4.3.2:
|
||
*
|
||
* The driver MUST NOT write to device_feature, num_queues,
|
||
* config_generation or queue_notify_off.
|
||
*/
|
||
errx(1, "%s: Unexpected write to offset %u", d->name, off);
|
||
}
|
||
|
||
|
||
/*
|
||
* 4.1.3.1:
|
||
*
|
||
* The driver MUST access each field using the “natural” access
|
||
* method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
|
||
* 16-bit fields and 8-bit accesses for 8-bit fields.
|
||
*/
|
||
write_through32:
|
||
if (mask != 0xFFFFFFFF) {
|
||
errx(1, "%s: non-32-bit write to offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
return;
|
||
}
|
||
memcpy((char *)d->mmio + off, &val, 4);
|
||
return;
|
||
|
||
write_through16:
|
||
if (mask != 0xFFFF)
|
||
errx(1, "%s: non-16-bit (%#x) write to offset %u (%#x)",
|
||
d->name, mask, off, getreg(eip));
|
||
memcpy((char *)d->mmio + off, &val, 2);
|
||
return;
|
||
|
||
write_through8:
|
||
if (mask != 0xFF)
|
||
errx(1, "%s: non-8-bit write to offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
memcpy((char *)d->mmio + off, &val, 1);
|
||
return;
|
||
}
|
||
|
||
static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask)
|
||
{
|
||
u8 isr;
|
||
u32 val = 0;
|
||
|
||
switch (off) {
|
||
case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
|
||
case offsetof(struct virtio_pci_mmio, cfg.device_feature):
|
||
case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
|
||
case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
|
||
goto read_through32;
|
||
case offsetof(struct virtio_pci_mmio, cfg.msix_config):
|
||
errx(1, "%s: read of msix_config", d->name);
|
||
case offsetof(struct virtio_pci_mmio, cfg.num_queues):
|
||
goto read_through16;
|
||
case offsetof(struct virtio_pci_mmio, cfg.device_status):
|
||
case offsetof(struct virtio_pci_mmio, cfg.config_generation):
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST present a changed config_generation after
|
||
* the driver has read a device-specific configuration value
|
||
* which has changed since any part of the device-specific
|
||
* configuration was last read.
|
||
*
|
||
* This is simple: none of our devices change config, so this
|
||
* is always 0.
|
||
*/
|
||
goto read_through8;
|
||
case offsetof(struct virtio_pci_mmio, notify):
|
||
goto read_through16;
|
||
case offsetof(struct virtio_pci_mmio, isr):
|
||
if (mask != 0xFF)
|
||
errx(1, "%s: non-8-bit read from offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
isr = d->mmio->isr;
|
||
/*
|
||
* 4.1.4.5.1:
|
||
*
|
||
* The device MUST reset ISR status to 0 on driver read.
|
||
*/
|
||
d->mmio->isr = 0;
|
||
return isr;
|
||
case offsetof(struct virtio_pci_mmio, padding):
|
||
errx(1, "%s: read from padding (%#x)",
|
||
d->name, getreg(eip));
|
||
default:
|
||
/* Read from device config space, beware unaligned overflow */
|
||
if (off > d->mmio_size - 4)
|
||
errx(1, "%s: read past end (%#x)",
|
||
d->name, getreg(eip));
|
||
if (mask == 0xFFFFFFFF)
|
||
goto read_through32;
|
||
else if (mask == 0xFFFF)
|
||
goto read_through16;
|
||
else
|
||
goto read_through8;
|
||
}
|
||
|
||
/*
|
||
* 4.1.3.1:
|
||
*
|
||
* The driver MUST access each field using the “natural” access
|
||
* method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
|
||
* 16-bit fields and 8-bit accesses for 8-bit fields.
|
||
*/
|
||
read_through32:
|
||
if (mask != 0xFFFFFFFF)
|
||
errx(1, "%s: non-32-bit read to offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
memcpy(&val, (char *)d->mmio + off, 4);
|
||
return val;
|
||
|
||
read_through16:
|
||
if (mask != 0xFFFF)
|
||
errx(1, "%s: non-16-bit read to offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
memcpy(&val, (char *)d->mmio + off, 2);
|
||
return val;
|
||
|
||
read_through8:
|
||
if (mask != 0xFF)
|
||
errx(1, "%s: non-8-bit read to offset %u (%#x)",
|
||
d->name, off, getreg(eip));
|
||
memcpy(&val, (char *)d->mmio + off, 1);
|
||
return val;
|
||
}
|
||
|
||
static void emulate_mmio(unsigned long paddr, const u8 *insn)
|
||
{
|
||
u32 val, off, mask = 0xFFFFFFFF, insnlen = 0;
|
||
struct device *d = find_mmio_region(paddr, &off);
|
||
unsigned long args[] = { LHREQ_TRAP, 14 };
|
||
|
||
if (!d) {
|
||
warnx("MMIO touching %#08lx (not a device)", paddr);
|
||
goto reinject;
|
||
}
|
||
|
||
/* Prefix makes it a 16 bit op */
|
||
if (insn[0] == 0x66) {
|
||
mask = 0xFFFF;
|
||
insnlen++;
|
||
}
|
||
|
||
/* iowrite */
|
||
if (insn[insnlen] == 0x89) {
|
||
/* Next byte is r/m byte: bits 3-5 are register. */
|
||
val = getreg_num((insn[insnlen+1] >> 3) & 0x7, mask);
|
||
emulate_mmio_write(d, off, val, mask);
|
||
insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
|
||
} else if (insn[insnlen] == 0x8b) { /* ioread */
|
||
/* Next byte is r/m byte: bits 3-5 are register. */
|
||
val = emulate_mmio_read(d, off, mask);
|
||
setreg_num((insn[insnlen+1] >> 3) & 0x7, val, mask);
|
||
insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
|
||
} else if (insn[0] == 0x88) { /* 8-bit iowrite */
|
||
mask = 0xff;
|
||
/* Next byte is r/m byte: bits 3-5 are register. */
|
||
val = getreg_num((insn[1] >> 3) & 0x7, mask);
|
||
emulate_mmio_write(d, off, val, mask);
|
||
insnlen = 2 + insn_displacement_len(insn[1]);
|
||
} else if (insn[0] == 0x8a) { /* 8-bit ioread */
|
||
mask = 0xff;
|
||
val = emulate_mmio_read(d, off, mask);
|
||
setreg_num((insn[1] >> 3) & 0x7, val, mask);
|
||
insnlen = 2 + insn_displacement_len(insn[1]);
|
||
} else {
|
||
warnx("Unknown MMIO instruction touching %#08lx:"
|
||
" %02x %02x %02x %02x at %u",
|
||
paddr, insn[0], insn[1], insn[2], insn[3], getreg(eip));
|
||
reinject:
|
||
/* Inject trap into Guest. */
|
||
if (write(lguest_fd, args, sizeof(args)) < 0)
|
||
err(1, "Reinjecting trap 14 for fault at %#x",
|
||
getreg(eip));
|
||
return;
|
||
}
|
||
|
||
/* Finally, we've "done" the instruction, so move past it. */
|
||
setreg(eip, getreg(eip) + insnlen);
|
||
}
|
||
|
||
/*L:190
|
||
* Device Setup
|
||
*
|
||
* All devices need a descriptor so the Guest knows it exists, and a "struct
|
||
* device" so the Launcher can keep track of it. We have common helper
|
||
* routines to allocate and manage them.
|
||
*/
|
||
static void add_pci_virtqueue(struct device *dev,
|
||
void (*service)(struct virtqueue *))
|
||
{
|
||
struct virtqueue **i, *vq = malloc(sizeof(*vq));
|
||
|
||
/* Initialize the virtqueue */
|
||
vq->next = NULL;
|
||
vq->last_avail_idx = 0;
|
||
vq->dev = dev;
|
||
|
||
/*
|
||
* This is the routine the service thread will run, and its Process ID
|
||
* once it's running.
|
||
*/
|
||
vq->service = service;
|
||
vq->thread = (pid_t)-1;
|
||
|
||
/* Initialize the configuration. */
|
||
reset_vq_pci_config(vq);
|
||
vq->pci_config.queue_notify_off = 0;
|
||
|
||
/* Add one to the number of queues */
|
||
vq->dev->mmio->cfg.num_queues++;
|
||
|
||
/*
|
||
* Add to tail of list, so dev->vq is first vq, dev->vq->next is
|
||
* second.
|
||
*/
|
||
for (i = &dev->vq; *i; i = &(*i)->next);
|
||
*i = vq;
|
||
}
|
||
|
||
/* The Guest accesses the feature bits via the PCI common config MMIO region */
|
||
static void add_pci_feature(struct device *dev, unsigned bit)
|
||
{
|
||
dev->features |= (1ULL << bit);
|
||
}
|
||
|
||
/* For devices with no config. */
|
||
static void no_device_config(struct device *dev)
|
||
{
|
||
dev->mmio_addr = get_mmio_region(dev->mmio_size);
|
||
|
||
dev->config.bar[0] = dev->mmio_addr;
|
||
/* Bottom 4 bits must be zero */
|
||
assert(~(dev->config.bar[0] & 0xF));
|
||
}
|
||
|
||
/* This puts the device config into BAR0 */
|
||
static void set_device_config(struct device *dev, const void *conf, size_t len)
|
||
{
|
||
/* Set up BAR 0 */
|
||
dev->mmio_size += len;
|
||
dev->mmio = realloc(dev->mmio, dev->mmio_size);
|
||
memcpy(dev->mmio + 1, conf, len);
|
||
|
||
/*
|
||
* 4.1.4.6:
|
||
*
|
||
* The device MUST present at least one VIRTIO_PCI_CAP_DEVICE_CFG
|
||
* capability for any device type which has a device-specific
|
||
* configuration.
|
||
*/
|
||
/* Hook up device cfg */
|
||
dev->config.cfg_access.cap.cap_next
|
||
= offsetof(struct pci_config, device);
|
||
|
||
/*
|
||
* 4.1.4.6.1:
|
||
*
|
||
* The offset for the device-specific configuration MUST be 4-byte
|
||
* aligned.
|
||
*/
|
||
assert(dev->config.cfg_access.cap.cap_next % 4 == 0);
|
||
|
||
/* Fix up device cfg field length. */
|
||
dev->config.device.length = len;
|
||
|
||
/* The rest is the same as the no-config case */
|
||
no_device_config(dev);
|
||
}
|
||
|
||
static void init_cap(struct virtio_pci_cap *cap, size_t caplen, int type,
|
||
size_t bar_offset, size_t bar_bytes, u8 next)
|
||
{
|
||
cap->cap_vndr = PCI_CAP_ID_VNDR;
|
||
cap->cap_next = next;
|
||
cap->cap_len = caplen;
|
||
cap->cfg_type = type;
|
||
cap->bar = 0;
|
||
memset(cap->padding, 0, sizeof(cap->padding));
|
||
cap->offset = bar_offset;
|
||
cap->length = bar_bytes;
|
||
}
|
||
|
||
/*
|
||
* This sets up the pci_config structure, as defined in the virtio 1.0
|
||
* standard (and PCI standard).
|
||
*/
|
||
static void init_pci_config(struct pci_config *pci, u16 type,
|
||
u8 class, u8 subclass)
|
||
{
|
||
size_t bar_offset, bar_len;
|
||
|
||
/*
|
||
* 4.1.4.4.1:
|
||
*
|
||
* The device MUST either present notify_off_multiplier as an even
|
||
* power of 2, or present notify_off_multiplier as 0.
|
||
*/
|
||
memset(pci, 0, sizeof(*pci));
|
||
|
||
/* 4.1.2.1: Devices MUST have the PCI Vendor ID 0x1AF4 */
|
||
pci->vendor_id = 0x1AF4;
|
||
/* 4.1.2.1: ... PCI Device ID calculated by adding 0x1040 ... */
|
||
pci->device_id = 0x1040 + type;
|
||
|
||
/*
|
||
* PCI have specific codes for different types of devices.
|
||
* Linux doesn't care, but it's a good clue for people looking
|
||
* at the device.
|
||
*/
|
||
pci->class = class;
|
||
pci->subclass = subclass;
|
||
|
||
/*
|
||
* 4.1.2.1:
|
||
*
|
||
* Non-transitional devices SHOULD have a PCI Revision ID of 1 or
|
||
* higher
|
||
*/
|
||
pci->revid = 1;
|
||
|
||
/*
|
||
* 4.1.2.1:
|
||
*
|
||
* Non-transitional devices SHOULD have a PCI Subsystem Device ID of
|
||
* 0x40 or higher.
|
||
*/
|
||
pci->subsystem_device_id = 0x40;
|
||
|
||
/* We use our dummy interrupt controller, and irq_line is the irq */
|
||
pci->irq_line = devices.next_irq++;
|
||
pci->irq_pin = 0;
|
||
|
||
/* Support for extended capabilities. */
|
||
pci->status = (1 << 4);
|
||
|
||
/* Link them in. */
|
||
/*
|
||
* 4.1.4.3.1:
|
||
*
|
||
* The device MUST present at least one common configuration
|
||
* capability.
|
||
*/
|
||
pci->capabilities = offsetof(struct pci_config, common);
|
||
|
||
/* 4.1.4.3.1 ... offset MUST be 4-byte aligned. */
|
||
assert(pci->capabilities % 4 == 0);
|
||
|
||
bar_offset = offsetof(struct virtio_pci_mmio, cfg);
|
||
bar_len = sizeof(((struct virtio_pci_mmio *)0)->cfg);
|
||
init_cap(&pci->common, sizeof(pci->common), VIRTIO_PCI_CAP_COMMON_CFG,
|
||
bar_offset, bar_len,
|
||
offsetof(struct pci_config, notify));
|
||
|
||
/*
|
||
* 4.1.4.4.1:
|
||
*
|
||
* The device MUST present at least one notification capability.
|
||
*/
|
||
bar_offset += bar_len;
|
||
bar_len = sizeof(((struct virtio_pci_mmio *)0)->notify);
|
||
|
||
/*
|
||
* 4.1.4.4.1:
|
||
*
|
||
* The cap.offset MUST be 2-byte aligned.
|
||
*/
|
||
assert(pci->common.cap_next % 2 == 0);
|
||
|
||
/* FIXME: Use a non-zero notify_off, for per-queue notification? */
|
||
/*
|
||
* 4.1.4.4.1:
|
||
*
|
||
* The value cap.length presented by the device MUST be at least 2 and
|
||
* MUST be large enough to support queue notification offsets for all
|
||
* supported queues in all possible configurations.
|
||
*/
|
||
assert(bar_len >= 2);
|
||
|
||
init_cap(&pci->notify.cap, sizeof(pci->notify),
|
||
VIRTIO_PCI_CAP_NOTIFY_CFG,
|
||
bar_offset, bar_len,
|
||
offsetof(struct pci_config, isr));
|
||
|
||
bar_offset += bar_len;
|
||
bar_len = sizeof(((struct virtio_pci_mmio *)0)->isr);
|
||
/*
|
||
* 4.1.4.5.1:
|
||
*
|
||
* The device MUST present at least one VIRTIO_PCI_CAP_ISR_CFG
|
||
* capability.
|
||
*/
|
||
init_cap(&pci->isr, sizeof(pci->isr),
|
||
VIRTIO_PCI_CAP_ISR_CFG,
|
||
bar_offset, bar_len,
|
||
offsetof(struct pci_config, cfg_access));
|
||
|
||
/*
|
||
* 4.1.4.7.1:
|
||
*
|
||
* The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG
|
||
* capability.
|
||
*/
|
||
/* This doesn't have any presence in the BAR */
|
||
init_cap(&pci->cfg_access.cap, sizeof(pci->cfg_access),
|
||
VIRTIO_PCI_CAP_PCI_CFG,
|
||
0, 0, 0);
|
||
|
||
bar_offset += bar_len + sizeof(((struct virtio_pci_mmio *)0)->padding);
|
||
assert(bar_offset == sizeof(struct virtio_pci_mmio));
|
||
|
||
/*
|
||
* This gets sewn in and length set in set_device_config().
|
||
* Some devices don't have a device configuration interface, so
|
||
* we never expose this if we don't call set_device_config().
|
||
*/
|
||
init_cap(&pci->device, sizeof(pci->device), VIRTIO_PCI_CAP_DEVICE_CFG,
|
||
bar_offset, 0, 0);
|
||
}
|
||
|
||
/*
|
||
* This routine does all the creation and setup of a new device, but we don't
|
||
* actually place the MMIO region until we know the size (if any) of the
|
||
* device-specific config. And we don't actually start the service threads
|
||
* until later.
|
||
*
|
||
* See what I mean about userspace being boring?
|
||
*/
|
||
static struct device *new_pci_device(const char *name, u16 type,
|
||
u8 class, u8 subclass)
|
||
{
|
||
struct device *dev = malloc(sizeof(*dev));
|
||
|
||
/* Now we populate the fields one at a time. */
|
||
dev->name = name;
|
||
dev->vq = NULL;
|
||
dev->running = false;
|
||
dev->mmio_size = sizeof(struct virtio_pci_mmio);
|
||
dev->mmio = calloc(1, dev->mmio_size);
|
||
dev->features = (u64)1 << VIRTIO_F_VERSION_1;
|
||
dev->features_accepted = 0;
|
||
|
||
if (devices.device_num + 1 >= MAX_PCI_DEVICES)
|
||
errx(1, "Can only handle 31 PCI devices");
|
||
|
||
init_pci_config(&dev->config, type, class, subclass);
|
||
assert(!devices.pci[devices.device_num+1]);
|
||
devices.pci[++devices.device_num] = dev;
|
||
|
||
return dev;
|
||
}
|
||
|
||
/*
|
||
* Our first setup routine is the console. It's a fairly simple device, but
|
||
* UNIX tty handling makes it uglier than it could be.
|
||
*/
|
||
static void setup_console(void)
|
||
{
|
||
struct device *dev;
|
||
struct virtio_console_config conf;
|
||
|
||
/* If we can save the initial standard input settings... */
|
||
if (tcgetattr(STDIN_FILENO, &orig_term) == 0) {
|
||
struct termios term = orig_term;
|
||
/*
|
||
* Then we turn off echo, line buffering and ^C etc: We want a
|
||
* raw input stream to the Guest.
|
||
*/
|
||
term.c_lflag &= ~(ISIG|ICANON|ECHO);
|
||
tcsetattr(STDIN_FILENO, TCSANOW, &term);
|
||
}
|
||
|
||
dev = new_pci_device("console", VIRTIO_ID_CONSOLE, 0x07, 0x00);
|
||
|
||
/* We store the console state in dev->priv, and initialize it. */
|
||
dev->priv = malloc(sizeof(struct console_abort));
|
||
((struct console_abort *)dev->priv)->count = 0;
|
||
|
||
/*
|
||
* The console needs two virtqueues: the input then the output. When
|
||
* they put something the input queue, we make sure we're listening to
|
||
* stdin. When they put something in the output queue, we write it to
|
||
* stdout.
|
||
*/
|
||
add_pci_virtqueue(dev, console_input);
|
||
add_pci_virtqueue(dev, console_output);
|
||
|
||
/* We need a configuration area for the emerg_wr early writes. */
|
||
add_pci_feature(dev, VIRTIO_CONSOLE_F_EMERG_WRITE);
|
||
set_device_config(dev, &conf, sizeof(conf));
|
||
|
||
verbose("device %u: console\n", devices.device_num);
|
||
}
|
||
/*:*/
|
||
|
||
/*M:010
|
||
* Inter-guest networking is an interesting area. Simplest is to have a
|
||
* --sharenet=<name> option which opens or creates a named pipe. This can be
|
||
* used to send packets to another guest in a 1:1 manner.
|
||
*
|
||
* More sophisticated is to use one of the tools developed for project like UML
|
||
* to do networking.
|
||
*
|
||
* Faster is to do virtio bonding in kernel. Doing this 1:1 would be
|
||
* completely generic ("here's my vring, attach to your vring") and would work
|
||
* for any traffic. Of course, namespace and permissions issues need to be
|
||
* dealt with. A more sophisticated "multi-channel" virtio_net.c could hide
|
||
* multiple inter-guest channels behind one interface, although it would
|
||
* require some manner of hotplugging new virtio channels.
|
||
*
|
||
* Finally, we could use a virtio network switch in the kernel, ie. vhost.
|
||
:*/
|
||
|
||
static u32 str2ip(const char *ipaddr)
|
||
{
|
||
unsigned int b[4];
|
||
|
||
if (sscanf(ipaddr, "%u.%u.%u.%u", &b[0], &b[1], &b[2], &b[3]) != 4)
|
||
errx(1, "Failed to parse IP address '%s'", ipaddr);
|
||
return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
|
||
}
|
||
|
||
static void str2mac(const char *macaddr, unsigned char mac[6])
|
||
{
|
||
unsigned int m[6];
|
||
if (sscanf(macaddr, "%02x:%02x:%02x:%02x:%02x:%02x",
|
||
&m[0], &m[1], &m[2], &m[3], &m[4], &m[5]) != 6)
|
||
errx(1, "Failed to parse mac address '%s'", macaddr);
|
||
mac[0] = m[0];
|
||
mac[1] = m[1];
|
||
mac[2] = m[2];
|
||
mac[3] = m[3];
|
||
mac[4] = m[4];
|
||
mac[5] = m[5];
|
||
}
|
||
|
||
/*
|
||
* This code is "adapted" from libbridge: it attaches the Host end of the
|
||
* network device to the bridge device specified by the command line.
|
||
*
|
||
* This is yet another James Morris contribution (I'm an IP-level guy, so I
|
||
* dislike bridging), and I just try not to break it.
|
||
*/
|
||
static void add_to_bridge(int fd, const char *if_name, const char *br_name)
|
||
{
|
||
int ifidx;
|
||
struct ifreq ifr;
|
||
|
||
if (!*br_name)
|
||
errx(1, "must specify bridge name");
|
||
|
||
ifidx = if_nametoindex(if_name);
|
||
if (!ifidx)
|
||
errx(1, "interface %s does not exist!", if_name);
|
||
|
||
strncpy(ifr.ifr_name, br_name, IFNAMSIZ);
|
||
ifr.ifr_name[IFNAMSIZ-1] = '\0';
|
||
ifr.ifr_ifindex = ifidx;
|
||
if (ioctl(fd, SIOCBRADDIF, &ifr) < 0)
|
||
err(1, "can't add %s to bridge %s", if_name, br_name);
|
||
}
|
||
|
||
/*
|
||
* This sets up the Host end of the network device with an IP address, brings
|
||
* it up so packets will flow, the copies the MAC address into the hwaddr
|
||
* pointer.
|
||
*/
|
||
static void configure_device(int fd, const char *tapif, u32 ipaddr)
|
||
{
|
||
struct ifreq ifr;
|
||
struct sockaddr_in sin;
|
||
|
||
memset(&ifr, 0, sizeof(ifr));
|
||
strcpy(ifr.ifr_name, tapif);
|
||
|
||
/* Don't read these incantations. Just cut & paste them like I did! */
|
||
sin.sin_family = AF_INET;
|
||
sin.sin_addr.s_addr = htonl(ipaddr);
|
||
memcpy(&ifr.ifr_addr, &sin, sizeof(sin));
|
||
if (ioctl(fd, SIOCSIFADDR, &ifr) != 0)
|
||
err(1, "Setting %s interface address", tapif);
|
||
ifr.ifr_flags = IFF_UP;
|
||
if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0)
|
||
err(1, "Bringing interface %s up", tapif);
|
||
}
|
||
|
||
static int get_tun_device(char tapif[IFNAMSIZ])
|
||
{
|
||
struct ifreq ifr;
|
||
int vnet_hdr_sz;
|
||
int netfd;
|
||
|
||
/* Start with this zeroed. Messy but sure. */
|
||
memset(&ifr, 0, sizeof(ifr));
|
||
|
||
/*
|
||
* We open the /dev/net/tun device and tell it we want a tap device. A
|
||
* tap device is like a tun device, only somehow different. To tell
|
||
* the truth, I completely blundered my way through this code, but it
|
||
* works now!
|
||
*/
|
||
netfd = open_or_die("/dev/net/tun", O_RDWR);
|
||
ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR;
|
||
strcpy(ifr.ifr_name, "tap%d");
|
||
if (ioctl(netfd, TUNSETIFF, &ifr) != 0)
|
||
err(1, "configuring /dev/net/tun");
|
||
|
||
if (ioctl(netfd, TUNSETOFFLOAD,
|
||
TUN_F_CSUM|TUN_F_TSO4|TUN_F_TSO6|TUN_F_TSO_ECN) != 0)
|
||
err(1, "Could not set features for tun device");
|
||
|
||
/*
|
||
* We don't need checksums calculated for packets coming in this
|
||
* device: trust us!
|
||
*/
|
||
ioctl(netfd, TUNSETNOCSUM, 1);
|
||
|
||
/*
|
||
* In virtio before 1.0 (aka legacy virtio), we added a 16-bit
|
||
* field at the end of the network header iff
|
||
* VIRTIO_NET_F_MRG_RXBUF was negotiated. For virtio 1.0,
|
||
* that became the norm, but we need to tell the tun device
|
||
* about our expanded header (which is called
|
||
* virtio_net_hdr_mrg_rxbuf in the legacy system).
|
||
*/
|
||
vnet_hdr_sz = sizeof(struct virtio_net_hdr_mrg_rxbuf);
|
||
if (ioctl(netfd, TUNSETVNETHDRSZ, &vnet_hdr_sz) != 0)
|
||
err(1, "Setting tun header size to %u", vnet_hdr_sz);
|
||
|
||
memcpy(tapif, ifr.ifr_name, IFNAMSIZ);
|
||
return netfd;
|
||
}
|
||
|
||
/*L:195
|
||
* Our network is a Host<->Guest network. This can either use bridging or
|
||
* routing, but the principle is the same: it uses the "tun" device to inject
|
||
* packets into the Host as if they came in from a normal network card. We
|
||
* just shunt packets between the Guest and the tun device.
|
||
*/
|
||
static void setup_tun_net(char *arg)
|
||
{
|
||
struct device *dev;
|
||
struct net_info *net_info = malloc(sizeof(*net_info));
|
||
int ipfd;
|
||
u32 ip = INADDR_ANY;
|
||
bool bridging = false;
|
||
char tapif[IFNAMSIZ], *p;
|
||
struct virtio_net_config conf;
|
||
|
||
net_info->tunfd = get_tun_device(tapif);
|
||
|
||
/* First we create a new network device. */
|
||
dev = new_pci_device("net", VIRTIO_ID_NET, 0x02, 0x00);
|
||
dev->priv = net_info;
|
||
|
||
/* Network devices need a recv and a send queue, just like console. */
|
||
add_pci_virtqueue(dev, net_input);
|
||
add_pci_virtqueue(dev, net_output);
|
||
|
||
/*
|
||
* We need a socket to perform the magic network ioctls to bring up the
|
||
* tap interface, connect to the bridge etc. Any socket will do!
|
||
*/
|
||
ipfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
|
||
if (ipfd < 0)
|
||
err(1, "opening IP socket");
|
||
|
||
/* If the command line was --tunnet=bridge:<name> do bridging. */
|
||
if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) {
|
||
arg += strlen(BRIDGE_PFX);
|
||
bridging = true;
|
||
}
|
||
|
||
/* A mac address may follow the bridge name or IP address */
|
||
p = strchr(arg, ':');
|
||
if (p) {
|
||
str2mac(p+1, conf.mac);
|
||
add_pci_feature(dev, VIRTIO_NET_F_MAC);
|
||
*p = '\0';
|
||
}
|
||
|
||
/* arg is now either an IP address or a bridge name */
|
||
if (bridging)
|
||
add_to_bridge(ipfd, tapif, arg);
|
||
else
|
||
ip = str2ip(arg);
|
||
|
||
/* Set up the tun device. */
|
||
configure_device(ipfd, tapif, ip);
|
||
|
||
/* Expect Guest to handle everything except UFO */
|
||
add_pci_feature(dev, VIRTIO_NET_F_CSUM);
|
||
add_pci_feature(dev, VIRTIO_NET_F_GUEST_CSUM);
|
||
add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO4);
|
||
add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO6);
|
||
add_pci_feature(dev, VIRTIO_NET_F_GUEST_ECN);
|
||
add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO4);
|
||
add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO6);
|
||
add_pci_feature(dev, VIRTIO_NET_F_HOST_ECN);
|
||
/* We handle indirect ring entries */
|
||
add_pci_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
|
||
set_device_config(dev, &conf, sizeof(conf));
|
||
|
||
/* We don't need the socket any more; setup is done. */
|
||
close(ipfd);
|
||
|
||
if (bridging)
|
||
verbose("device %u: tun %s attached to bridge: %s\n",
|
||
devices.device_num, tapif, arg);
|
||
else
|
||
verbose("device %u: tun %s: %s\n",
|
||
devices.device_num, tapif, arg);
|
||
}
|
||
/*:*/
|
||
|
||
/* This hangs off device->priv. */
|
||
struct vblk_info {
|
||
/* The size of the file. */
|
||
off64_t len;
|
||
|
||
/* The file descriptor for the file. */
|
||
int fd;
|
||
|
||
};
|
||
|
||
/*L:210
|
||
* The Disk
|
||
*
|
||
* The disk only has one virtqueue, so it only has one thread. It is really
|
||
* simple: the Guest asks for a block number and we read or write that position
|
||
* in the file.
|
||
*
|
||
* Before we serviced each virtqueue in a separate thread, that was unacceptably
|
||
* slow: the Guest waits until the read is finished before running anything
|
||
* else, even if it could have been doing useful work.
|
||
*
|
||
* We could have used async I/O, except it's reputed to suck so hard that
|
||
* characters actually go missing from your code when you try to use it.
|
||
*/
|
||
static void blk_request(struct virtqueue *vq)
|
||
{
|
||
struct vblk_info *vblk = vq->dev->priv;
|
||
unsigned int head, out_num, in_num, wlen;
|
||
int ret, i;
|
||
u8 *in;
|
||
struct virtio_blk_outhdr out;
|
||
struct iovec iov[vq->vring.num];
|
||
off64_t off;
|
||
|
||
/*
|
||
* Get the next request, where we normally wait. It triggers the
|
||
* interrupt to acknowledge previously serviced requests (if any).
|
||
*/
|
||
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
|
||
|
||
/* Copy the output header from the front of the iov (adjusts iov) */
|
||
iov_consume(iov, out_num, &out, sizeof(out));
|
||
|
||
/* Find and trim end of iov input array, for our status byte. */
|
||
in = NULL;
|
||
for (i = out_num + in_num - 1; i >= out_num; i--) {
|
||
if (iov[i].iov_len > 0) {
|
||
in = iov[i].iov_base + iov[i].iov_len - 1;
|
||
iov[i].iov_len--;
|
||
break;
|
||
}
|
||
}
|
||
if (!in)
|
||
errx(1, "Bad virtblk cmd with no room for status");
|
||
|
||
/*
|
||
* For historical reasons, block operations are expressed in 512 byte
|
||
* "sectors".
|
||
*/
|
||
off = out.sector * 512;
|
||
|
||
if (out.type & VIRTIO_BLK_T_OUT) {
|
||
/*
|
||
* Write
|
||
*
|
||
* Move to the right location in the block file. This can fail
|
||
* if they try to write past end.
|
||
*/
|
||
if (lseek64(vblk->fd, off, SEEK_SET) != off)
|
||
err(1, "Bad seek to sector %llu", out.sector);
|
||
|
||
ret = writev(vblk->fd, iov, out_num);
|
||
verbose("WRITE to sector %llu: %i\n", out.sector, ret);
|
||
|
||
/*
|
||
* Grr... Now we know how long the descriptor they sent was, we
|
||
* make sure they didn't try to write over the end of the block
|
||
* file (possibly extending it).
|
||
*/
|
||
if (ret > 0 && off + ret > vblk->len) {
|
||
/* Trim it back to the correct length */
|
||
ftruncate64(vblk->fd, vblk->len);
|
||
/* Die, bad Guest, die. */
|
||
errx(1, "Write past end %llu+%u", off, ret);
|
||
}
|
||
|
||
wlen = sizeof(*in);
|
||
*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
|
||
} else if (out.type & VIRTIO_BLK_T_FLUSH) {
|
||
/* Flush */
|
||
ret = fdatasync(vblk->fd);
|
||
verbose("FLUSH fdatasync: %i\n", ret);
|
||
wlen = sizeof(*in);
|
||
*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
|
||
} else {
|
||
/*
|
||
* Read
|
||
*
|
||
* Move to the right location in the block file. This can fail
|
||
* if they try to read past end.
|
||
*/
|
||
if (lseek64(vblk->fd, off, SEEK_SET) != off)
|
||
err(1, "Bad seek to sector %llu", out.sector);
|
||
|
||
ret = readv(vblk->fd, iov + out_num, in_num);
|
||
if (ret >= 0) {
|
||
wlen = sizeof(*in) + ret;
|
||
*in = VIRTIO_BLK_S_OK;
|
||
} else {
|
||
wlen = sizeof(*in);
|
||
*in = VIRTIO_BLK_S_IOERR;
|
||
}
|
||
}
|
||
|
||
/* Finished that request. */
|
||
add_used(vq, head, wlen);
|
||
}
|
||
|
||
/*L:198 This actually sets up a virtual block device. */
|
||
static void setup_block_file(const char *filename)
|
||
{
|
||
struct device *dev;
|
||
struct vblk_info *vblk;
|
||
struct virtio_blk_config conf;
|
||
|
||
/* Create the device. */
|
||
dev = new_pci_device("block", VIRTIO_ID_BLOCK, 0x01, 0x80);
|
||
|
||
/* The device has one virtqueue, where the Guest places requests. */
|
||
add_pci_virtqueue(dev, blk_request);
|
||
|
||
/* Allocate the room for our own bookkeeping */
|
||
vblk = dev->priv = malloc(sizeof(*vblk));
|
||
|
||
/* First we open the file and store the length. */
|
||
vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
|
||
vblk->len = lseek64(vblk->fd, 0, SEEK_END);
|
||
|
||
/* Tell Guest how many sectors this device has. */
|
||
conf.capacity = cpu_to_le64(vblk->len / 512);
|
||
|
||
/*
|
||
* Tell Guest not to put in too many descriptors at once: two are used
|
||
* for the in and out elements.
|
||
*/
|
||
add_pci_feature(dev, VIRTIO_BLK_F_SEG_MAX);
|
||
conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2);
|
||
|
||
set_device_config(dev, &conf, sizeof(struct virtio_blk_config));
|
||
|
||
verbose("device %u: virtblock %llu sectors\n",
|
||
devices.device_num, le64_to_cpu(conf.capacity));
|
||
}
|
||
|
||
/*L:211
|
||
* Our random number generator device reads from /dev/urandom into the Guest's
|
||
* input buffers. The usual case is that the Guest doesn't want random numbers
|
||
* and so has no buffers although /dev/urandom is still readable, whereas
|
||
* console is the reverse.
|
||
*
|
||
* The same logic applies, however.
|
||
*/
|
||
struct rng_info {
|
||
int rfd;
|
||
};
|
||
|
||
static void rng_input(struct virtqueue *vq)
|
||
{
|
||
int len;
|
||
unsigned int head, in_num, out_num, totlen = 0;
|
||
struct rng_info *rng_info = vq->dev->priv;
|
||
struct iovec iov[vq->vring.num];
|
||
|
||
/* First we need a buffer from the Guests's virtqueue. */
|
||
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
|
||
if (out_num)
|
||
errx(1, "Output buffers in rng?");
|
||
|
||
/*
|
||
* Just like the console write, we loop to cover the whole iovec.
|
||
* In this case, short reads actually happen quite a bit.
|
||
*/
|
||
while (!iov_empty(iov, in_num)) {
|
||
len = readv(rng_info->rfd, iov, in_num);
|
||
if (len <= 0)
|
||
err(1, "Read from /dev/urandom gave %i", len);
|
||
iov_consume(iov, in_num, NULL, len);
|
||
totlen += len;
|
||
}
|
||
|
||
/* Tell the Guest about the new input. */
|
||
add_used(vq, head, totlen);
|
||
}
|
||
|
||
/*L:199
|
||
* This creates a "hardware" random number device for the Guest.
|
||
*/
|
||
static void setup_rng(void)
|
||
{
|
||
struct device *dev;
|
||
struct rng_info *rng_info = malloc(sizeof(*rng_info));
|
||
|
||
/* Our device's private info simply contains the /dev/urandom fd. */
|
||
rng_info->rfd = open_or_die("/dev/urandom", O_RDONLY);
|
||
|
||
/* Create the new device. */
|
||
dev = new_pci_device("rng", VIRTIO_ID_RNG, 0xff, 0);
|
||
dev->priv = rng_info;
|
||
|
||
/* The device has one virtqueue, where the Guest places inbufs. */
|
||
add_pci_virtqueue(dev, rng_input);
|
||
|
||
/* We don't have any configuration space */
|
||
no_device_config(dev);
|
||
|
||
verbose("device %u: rng\n", devices.device_num);
|
||
}
|
||
/* That's the end of device setup. */
|
||
|
||
/*L:230 Reboot is pretty easy: clean up and exec() the Launcher afresh. */
|
||
static void __attribute__((noreturn)) restart_guest(void)
|
||
{
|
||
unsigned int i;
|
||
|
||
/*
|
||
* Since we don't track all open fds, we simply close everything beyond
|
||
* stderr.
|
||
*/
|
||
for (i = 3; i < FD_SETSIZE; i++)
|
||
close(i);
|
||
|
||
/* Reset all the devices (kills all threads). */
|
||
cleanup_devices();
|
||
|
||
execv(main_args[0], main_args);
|
||
err(1, "Could not exec %s", main_args[0]);
|
||
}
|
||
|
||
/*L:220
|
||
* Finally we reach the core of the Launcher which runs the Guest, serves
|
||
* its input and output, and finally, lays it to rest.
|
||
*/
|
||
static void __attribute__((noreturn)) run_guest(void)
|
||
{
|
||
for (;;) {
|
||
struct lguest_pending notify;
|
||
int readval;
|
||
|
||
/* We read from the /dev/lguest device to run the Guest. */
|
||
readval = pread(lguest_fd, ¬ify, sizeof(notify), cpu_id);
|
||
if (readval == sizeof(notify)) {
|
||
if (notify.trap == 13) {
|
||
verbose("Emulating instruction at %#x\n",
|
||
getreg(eip));
|
||
emulate_insn(notify.insn);
|
||
} else if (notify.trap == 14) {
|
||
verbose("Emulating MMIO at %#x\n",
|
||
getreg(eip));
|
||
emulate_mmio(notify.addr, notify.insn);
|
||
} else
|
||
errx(1, "Unknown trap %i addr %#08x\n",
|
||
notify.trap, notify.addr);
|
||
/* ENOENT means the Guest died. Reading tells us why. */
|
||
} else if (errno == ENOENT) {
|
||
char reason[1024] = { 0 };
|
||
pread(lguest_fd, reason, sizeof(reason)-1, cpu_id);
|
||
errx(1, "%s", reason);
|
||
/* ERESTART means that we need to reboot the guest */
|
||
} else if (errno == ERESTART) {
|
||
restart_guest();
|
||
/* Anything else means a bug or incompatible change. */
|
||
} else
|
||
err(1, "Running guest failed");
|
||
}
|
||
}
|
||
/*L:240
|
||
* This is the end of the Launcher. The good news: we are over halfway
|
||
* through! The bad news: the most fiendish part of the code still lies ahead
|
||
* of us.
|
||
*
|
||
* Are you ready? Take a deep breath and join me in the core of the Host, in
|
||
* "make Host".
|
||
:*/
|
||
|
||
static struct option opts[] = {
|
||
{ "verbose", 0, NULL, 'v' },
|
||
{ "tunnet", 1, NULL, 't' },
|
||
{ "block", 1, NULL, 'b' },
|
||
{ "rng", 0, NULL, 'r' },
|
||
{ "initrd", 1, NULL, 'i' },
|
||
{ "username", 1, NULL, 'u' },
|
||
{ "chroot", 1, NULL, 'c' },
|
||
{ NULL },
|
||
};
|
||
static void usage(void)
|
||
{
|
||
errx(1, "Usage: lguest [--verbose] "
|
||
"[--tunnet=(<ipaddr>:<macaddr>|bridge:<bridgename>:<macaddr>)\n"
|
||
"|--block=<filename>|--initrd=<filename>]...\n"
|
||
"<mem-in-mb> vmlinux [args...]");
|
||
}
|
||
|
||
/*L:105 The main routine is where the real work begins: */
|
||
int main(int argc, char *argv[])
|
||
{
|
||
/* Memory, code startpoint and size of the (optional) initrd. */
|
||
unsigned long mem = 0, start, initrd_size = 0;
|
||
/* Two temporaries. */
|
||
int i, c;
|
||
/* The boot information for the Guest. */
|
||
struct boot_params *boot;
|
||
/* If they specify an initrd file to load. */
|
||
const char *initrd_name = NULL;
|
||
|
||
/* Password structure for initgroups/setres[gu]id */
|
||
struct passwd *user_details = NULL;
|
||
|
||
/* Directory to chroot to */
|
||
char *chroot_path = NULL;
|
||
|
||
/* Save the args: we "reboot" by execing ourselves again. */
|
||
main_args = argv;
|
||
|
||
/*
|
||
* First we initialize the device list. We remember next interrupt
|
||
* number to use for devices (1: remember that 0 is used by the timer).
|
||
*/
|
||
devices.next_irq = 1;
|
||
|
||
/* We're CPU 0. In fact, that's the only CPU possible right now. */
|
||
cpu_id = 0;
|
||
|
||
/*
|
||
* We need to know how much memory so we can set up the device
|
||
* descriptor and memory pages for the devices as we parse the command
|
||
* line. So we quickly look through the arguments to find the amount
|
||
* of memory now.
|
||
*/
|
||
for (i = 1; i < argc; i++) {
|
||
if (argv[i][0] != '-') {
|
||
mem = atoi(argv[i]) * 1024 * 1024;
|
||
/*
|
||
* We start by mapping anonymous pages over all of
|
||
* guest-physical memory range. This fills it with 0,
|
||
* and ensures that the Guest won't be killed when it
|
||
* tries to access it.
|
||
*/
|
||
guest_base = map_zeroed_pages(mem / getpagesize()
|
||
+ DEVICE_PAGES);
|
||
guest_limit = mem;
|
||
guest_max = guest_mmio = mem + DEVICE_PAGES*getpagesize();
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* We always have a console device, and it's always device 1. */
|
||
setup_console();
|
||
|
||
/* The options are fairly straight-forward */
|
||
while ((c = getopt_long(argc, argv, "v", opts, NULL)) != EOF) {
|
||
switch (c) {
|
||
case 'v':
|
||
verbose = true;
|
||
break;
|
||
case 't':
|
||
setup_tun_net(optarg);
|
||
break;
|
||
case 'b':
|
||
setup_block_file(optarg);
|
||
break;
|
||
case 'r':
|
||
setup_rng();
|
||
break;
|
||
case 'i':
|
||
initrd_name = optarg;
|
||
break;
|
||
case 'u':
|
||
user_details = getpwnam(optarg);
|
||
if (!user_details)
|
||
err(1, "getpwnam failed, incorrect username?");
|
||
break;
|
||
case 'c':
|
||
chroot_path = optarg;
|
||
break;
|
||
default:
|
||
warnx("Unknown argument %s", argv[optind]);
|
||
usage();
|
||
}
|
||
}
|
||
/*
|
||
* After the other arguments we expect memory and kernel image name,
|
||
* followed by command line arguments for the kernel.
|
||
*/
|
||
if (optind + 2 > argc)
|
||
usage();
|
||
|
||
verbose("Guest base is at %p\n", guest_base);
|
||
|
||
/* Initialize the (fake) PCI host bridge device. */
|
||
init_pci_host_bridge();
|
||
|
||
/* Now we load the kernel */
|
||
start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));
|
||
|
||
/* Boot information is stashed at physical address 0 */
|
||
boot = from_guest_phys(0);
|
||
|
||
/* Map the initrd image if requested (at top of physical memory) */
|
||
if (initrd_name) {
|
||
initrd_size = load_initrd(initrd_name, mem);
|
||
/*
|
||
* These are the location in the Linux boot header where the
|
||
* start and size of the initrd are expected to be found.
|
||
*/
|
||
boot->hdr.ramdisk_image = mem - initrd_size;
|
||
boot->hdr.ramdisk_size = initrd_size;
|
||
/* The bootloader type 0xFF means "unknown"; that's OK. */
|
||
boot->hdr.type_of_loader = 0xFF;
|
||
}
|
||
|
||
/*
|
||
* The Linux boot header contains an "E820" memory map: ours is a
|
||
* simple, single region.
|
||
*/
|
||
boot->e820_entries = 1;
|
||
boot->e820_map[0] = ((struct e820entry) { 0, mem, E820_RAM });
|
||
/*
|
||
* The boot header contains a command line pointer: we put the command
|
||
* line after the boot header.
|
||
*/
|
||
boot->hdr.cmd_line_ptr = to_guest_phys(boot + 1);
|
||
/* We use a simple helper to copy the arguments separated by spaces. */
|
||
concat((char *)(boot + 1), argv+optind+2);
|
||
|
||
/* Set kernel alignment to 16M (CONFIG_PHYSICAL_ALIGN) */
|
||
boot->hdr.kernel_alignment = 0x1000000;
|
||
|
||
/* Boot protocol version: 2.07 supports the fields for lguest. */
|
||
boot->hdr.version = 0x207;
|
||
|
||
/* The hardware_subarch value of "1" tells the Guest it's an lguest. */
|
||
boot->hdr.hardware_subarch = 1;
|
||
|
||
/* Tell the entry path not to try to reload segment registers. */
|
||
boot->hdr.loadflags |= KEEP_SEGMENTS;
|
||
|
||
/* We tell the kernel to initialize the Guest. */
|
||
tell_kernel(start);
|
||
|
||
/* Ensure that we terminate if a device-servicing child dies. */
|
||
signal(SIGCHLD, kill_launcher);
|
||
|
||
/* If we exit via err(), this kills all the threads, restores tty. */
|
||
atexit(cleanup_devices);
|
||
|
||
/* If requested, chroot to a directory */
|
||
if (chroot_path) {
|
||
if (chroot(chroot_path) != 0)
|
||
err(1, "chroot(\"%s\") failed", chroot_path);
|
||
|
||
if (chdir("/") != 0)
|
||
err(1, "chdir(\"/\") failed");
|
||
|
||
verbose("chroot done\n");
|
||
}
|
||
|
||
/* If requested, drop privileges */
|
||
if (user_details) {
|
||
uid_t u;
|
||
gid_t g;
|
||
|
||
u = user_details->pw_uid;
|
||
g = user_details->pw_gid;
|
||
|
||
if (initgroups(user_details->pw_name, g) != 0)
|
||
err(1, "initgroups failed");
|
||
|
||
if (setresgid(g, g, g) != 0)
|
||
err(1, "setresgid failed");
|
||
|
||
if (setresuid(u, u, u) != 0)
|
||
err(1, "setresuid failed");
|
||
|
||
verbose("Dropping privileges completed\n");
|
||
}
|
||
|
||
/* Finally, run the Guest. This doesn't return. */
|
||
run_guest();
|
||
}
|
||
/*:*/
|
||
|
||
/*M:999
|
||
* Mastery is done: you now know everything I do.
|
||
*
|
||
* But surely you have seen code, features and bugs in your wanderings which
|
||
* you now yearn to attack? That is the real game, and I look forward to you
|
||
* patching and forking lguest into the Your-Name-Here-visor.
|
||
*
|
||
* Farewell, and good coding!
|
||
* Rusty Russell.
|
||
*/
|