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d7e28ffe6c
This is the code for the "lg.ko" module, which allows lguest guests to be launched. [akpm@linux-foundation.org: update for futex-new-private-futexes] [akpm@linux-foundation.org: build fix] [jmorris@namei.org: lguest: use hrtimers] [akpm@linux-foundation.org: x86_64 build fix] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
237 lines
5.2 KiB
C
237 lines
5.2 KiB
C
/* Userspace control of the guest, via /dev/lguest. */
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#include <linux/uaccess.h>
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#include <linux/miscdevice.h>
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#include <linux/fs.h>
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#include "lg.h"
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static void setup_regs(struct lguest_regs *regs, unsigned long start)
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{
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/* Write out stack in format lguest expects, so we can switch to it. */
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regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
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regs->cs = __KERNEL_CS|GUEST_PL;
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regs->eflags = 0x202; /* Interrupts enabled. */
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regs->eip = start;
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/* esi points to our boot information (physical address 0) */
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}
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/* + addr */
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static long user_get_dma(struct lguest *lg, const u32 __user *input)
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{
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unsigned long key, udma, irq;
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if (get_user(key, input) != 0)
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return -EFAULT;
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udma = get_dma_buffer(lg, key, &irq);
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if (!udma)
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return -ENOENT;
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/* We put irq number in udma->used_len. */
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lgwrite_u32(lg, udma + offsetof(struct lguest_dma, used_len), irq);
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return udma;
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}
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/* To force the Guest to stop running and return to the Launcher, the
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* Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest. The
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* Launcher then writes LHREQ_BREAK and "0" to release the Waker. */
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static int break_guest_out(struct lguest *lg, const u32 __user *input)
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{
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unsigned long on;
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/* Fetch whether they're turning break on or off.. */
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if (get_user(on, input) != 0)
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return -EFAULT;
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if (on) {
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lg->break_out = 1;
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/* Pop it out (may be running on different CPU) */
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wake_up_process(lg->tsk);
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/* Wait for them to reset it */
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return wait_event_interruptible(lg->break_wq, !lg->break_out);
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} else {
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lg->break_out = 0;
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wake_up(&lg->break_wq);
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return 0;
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}
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}
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/* + irq */
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static int user_send_irq(struct lguest *lg, const u32 __user *input)
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{
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u32 irq;
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if (get_user(irq, input) != 0)
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return -EFAULT;
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if (irq >= LGUEST_IRQS)
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return -EINVAL;
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set_bit(irq, lg->irqs_pending);
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return 0;
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}
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static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
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{
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struct lguest *lg = file->private_data;
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if (!lg)
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return -EINVAL;
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/* If you're not the task which owns the guest, go away. */
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if (current != lg->tsk)
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return -EPERM;
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if (lg->dead) {
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size_t len;
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if (IS_ERR(lg->dead))
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return PTR_ERR(lg->dead);
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len = min(size, strlen(lg->dead)+1);
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if (copy_to_user(user, lg->dead, len) != 0)
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return -EFAULT;
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return len;
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}
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if (lg->dma_is_pending)
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lg->dma_is_pending = 0;
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return run_guest(lg, (unsigned long __user *)user);
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}
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/* Take: pfnlimit, pgdir, start, pageoffset. */
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static int initialize(struct file *file, const u32 __user *input)
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{
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struct lguest *lg;
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int err, i;
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u32 args[4];
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/* We grab the Big Lguest lock, which protects the global array
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* "lguests" and multiple simultaneous initializations. */
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mutex_lock(&lguest_lock);
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if (file->private_data) {
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err = -EBUSY;
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goto unlock;
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}
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if (copy_from_user(args, input, sizeof(args)) != 0) {
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err = -EFAULT;
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goto unlock;
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}
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i = find_free_guest();
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if (i < 0) {
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err = -ENOSPC;
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goto unlock;
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}
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lg = &lguests[i];
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lg->guestid = i;
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lg->pfn_limit = args[0];
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lg->page_offset = args[3];
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lg->regs_page = get_zeroed_page(GFP_KERNEL);
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if (!lg->regs_page) {
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err = -ENOMEM;
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goto release_guest;
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}
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lg->regs = (void *)lg->regs_page + PAGE_SIZE - sizeof(*lg->regs);
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err = init_guest_pagetable(lg, args[1]);
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if (err)
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goto free_regs;
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setup_regs(lg->regs, args[2]);
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setup_guest_gdt(lg);
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init_clockdev(lg);
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lg->tsk = current;
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lg->mm = get_task_mm(lg->tsk);
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init_waitqueue_head(&lg->break_wq);
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lg->last_pages = NULL;
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file->private_data = lg;
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mutex_unlock(&lguest_lock);
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return sizeof(args);
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free_regs:
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free_page(lg->regs_page);
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release_guest:
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memset(lg, 0, sizeof(*lg));
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unlock:
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mutex_unlock(&lguest_lock);
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return err;
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}
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static ssize_t write(struct file *file, const char __user *input,
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size_t size, loff_t *off)
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{
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struct lguest *lg = file->private_data;
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u32 req;
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if (get_user(req, input) != 0)
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return -EFAULT;
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input += sizeof(req);
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if (req != LHREQ_INITIALIZE && !lg)
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return -EINVAL;
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if (lg && lg->dead)
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return -ENOENT;
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/* If you're not the task which owns the Guest, you can only break */
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if (lg && current != lg->tsk && req != LHREQ_BREAK)
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return -EPERM;
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switch (req) {
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case LHREQ_INITIALIZE:
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return initialize(file, (const u32 __user *)input);
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case LHREQ_GETDMA:
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return user_get_dma(lg, (const u32 __user *)input);
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case LHREQ_IRQ:
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return user_send_irq(lg, (const u32 __user *)input);
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case LHREQ_BREAK:
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return break_guest_out(lg, (const u32 __user *)input);
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default:
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return -EINVAL;
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}
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}
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static int close(struct inode *inode, struct file *file)
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{
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struct lguest *lg = file->private_data;
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if (!lg)
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return 0;
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mutex_lock(&lguest_lock);
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/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */
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hrtimer_cancel(&lg->hrt);
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release_all_dma(lg);
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free_guest_pagetable(lg);
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mmput(lg->mm);
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if (!IS_ERR(lg->dead))
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kfree(lg->dead);
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free_page(lg->regs_page);
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memset(lg, 0, sizeof(*lg));
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mutex_unlock(&lguest_lock);
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return 0;
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}
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static struct file_operations lguest_fops = {
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.owner = THIS_MODULE,
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.release = close,
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.write = write,
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.read = read,
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};
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static struct miscdevice lguest_dev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "lguest",
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.fops = &lguest_fops,
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};
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int __init lguest_device_init(void)
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{
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return misc_register(&lguest_dev);
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}
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void __exit lguest_device_remove(void)
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{
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misc_deregister(&lguest_dev);
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}
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