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qemu/hw/virtio/virtio-mmio.c
Cornelia Huck ab223c9518 virtio: allow virtio-1 queue layout 
For virtio-1 devices, we allow a more complex queue layout that doesn't
require descriptor table and rings on a physically-contigous memory area:
add virtio_queue_set_rings() to allow transports to set this up.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
2015-06-10 18:15:04 +02:00

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/*
* Virtio MMIO bindings
*
* Copyright (c) 2011 Linaro Limited
*
* Author:
* Peter Maydell <peter.maydell@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "hw/sysbus.h"
#include "hw/virtio/virtio.h"
#include "qemu/host-utils.h"
#include "sysemu/kvm.h"
#include "hw/virtio/virtio-bus.h"
#include "qemu/error-report.h"
/* #define DEBUG_VIRTIO_MMIO */
#ifdef DEBUG_VIRTIO_MMIO
#define DPRINTF(fmt, ...) \
do { printf("virtio_mmio: " fmt , ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) do {} while (0)
#endif
/* QOM macros */
/* virtio-mmio-bus */
#define TYPE_VIRTIO_MMIO_BUS "virtio-mmio-bus"
#define VIRTIO_MMIO_BUS(obj) \
OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_MMIO_BUS)
#define VIRTIO_MMIO_BUS_GET_CLASS(obj) \
OBJECT_GET_CLASS(VirtioBusClass, (obj), TYPE_VIRTIO_MMIO_BUS)
#define VIRTIO_MMIO_BUS_CLASS(klass) \
OBJECT_CLASS_CHECK(VirtioBusClass, (klass), TYPE_VIRTIO_MMIO_BUS)
/* virtio-mmio */
#define TYPE_VIRTIO_MMIO "virtio-mmio"
#define VIRTIO_MMIO(obj) \
OBJECT_CHECK(VirtIOMMIOProxy, (obj), TYPE_VIRTIO_MMIO)
/* Memory mapped register offsets */
#define VIRTIO_MMIO_MAGIC 0x0
#define VIRTIO_MMIO_VERSION 0x4
#define VIRTIO_MMIO_DEVICEID 0x8
#define VIRTIO_MMIO_VENDORID 0xc
#define VIRTIO_MMIO_HOSTFEATURES 0x10
#define VIRTIO_MMIO_HOSTFEATURESSEL 0x14
#define VIRTIO_MMIO_GUESTFEATURES 0x20
#define VIRTIO_MMIO_GUESTFEATURESSEL 0x24
#define VIRTIO_MMIO_GUESTPAGESIZE 0x28
#define VIRTIO_MMIO_QUEUESEL 0x30
#define VIRTIO_MMIO_QUEUENUMMAX 0x34
#define VIRTIO_MMIO_QUEUENUM 0x38
#define VIRTIO_MMIO_QUEUEALIGN 0x3c
#define VIRTIO_MMIO_QUEUEPFN 0x40
#define VIRTIO_MMIO_QUEUENOTIFY 0x50
#define VIRTIO_MMIO_INTERRUPTSTATUS 0x60
#define VIRTIO_MMIO_INTERRUPTACK 0x64
#define VIRTIO_MMIO_STATUS 0x70
/* Device specific config space starts here */
#define VIRTIO_MMIO_CONFIG 0x100
#define VIRT_MAGIC 0x74726976 /* 'virt' */
#define VIRT_VERSION 1
#define VIRT_VENDOR 0x554D4551 /* 'QEMU' */
typedef struct {
/* Generic */
SysBusDevice parent_obj;
MemoryRegion iomem;
qemu_irq irq;
/* Guest accessible state needing migration and reset */
uint32_t host_features_sel;
uint32_t guest_features_sel;
uint32_t guest_page_shift;
/* virtio-bus */
VirtioBusState bus;
bool ioeventfd_disabled;
bool ioeventfd_started;
} VirtIOMMIOProxy;
static int virtio_mmio_set_host_notifier_internal(VirtIOMMIOProxy *proxy,
int n, bool assign,
bool set_handler)
{
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
VirtQueue *vq = virtio_get_queue(vdev, n);
EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
int r = 0;
if (assign) {
r = event_notifier_init(notifier, 1);
if (r < 0) {
error_report("%s: unable to init event notifier: %d",
__func__, r);
return r;
}
virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
memory_region_add_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4,
true, n, notifier);
} else {
memory_region_del_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY, 4,
true, n, notifier);
virtio_queue_set_host_notifier_fd_handler(vq, false, false);
event_notifier_cleanup(notifier);
}
return r;
}
static void virtio_mmio_start_ioeventfd(VirtIOMMIOProxy *proxy)
{
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
int n, r;
if (!kvm_eventfds_enabled() ||
proxy->ioeventfd_disabled ||
proxy->ioeventfd_started) {
return;
}
for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
if (!virtio_queue_get_num(vdev, n)) {
continue;
}
r = virtio_mmio_set_host_notifier_internal(proxy, n, true, true);
if (r < 0) {
goto assign_error;
}
}
proxy->ioeventfd_started = true;
return;
assign_error:
while (--n >= 0) {
if (!virtio_queue_get_num(vdev, n)) {
continue;
}
r = virtio_mmio_set_host_notifier_internal(proxy, n, false, false);
assert(r >= 0);
}
proxy->ioeventfd_started = false;
error_report("%s: failed. Fallback to a userspace (slower).", __func__);
}
static void virtio_mmio_stop_ioeventfd(VirtIOMMIOProxy *proxy)
{
int r;
int n;
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
if (!proxy->ioeventfd_started) {
return;
}
for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
if (!virtio_queue_get_num(vdev, n)) {
continue;
}
r = virtio_mmio_set_host_notifier_internal(proxy, n, false, false);
assert(r >= 0);
}
proxy->ioeventfd_started = false;
}
static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
{
VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
DPRINTF("virtio_mmio_read offset 0x%x\n", (int)offset);
if (!vdev) {
/* If no backend is present, we treat most registers as
* read-as-zero, except for the magic number, version and
* vendor ID. This is not strictly sanctioned by the virtio
* spec, but it allows us to provide transports with no backend
* plugged in which don't confuse Linux's virtio code: the
* probe won't complain about the bad magic number, but the
* device ID of zero means no backend will claim it.
*/
switch (offset) {
case VIRTIO_MMIO_MAGIC:
return VIRT_MAGIC;
case VIRTIO_MMIO_VERSION:
return VIRT_VERSION;
case VIRTIO_MMIO_VENDORID:
return VIRT_VENDOR;
default:
return 0;
}
}
if (offset >= VIRTIO_MMIO_CONFIG) {
offset -= VIRTIO_MMIO_CONFIG;
switch (size) {
case 1:
return virtio_config_readb(vdev, offset);
case 2:
return virtio_config_readw(vdev, offset);
case 4:
return virtio_config_readl(vdev, offset);
default:
abort();
}
}
if (size != 4) {
DPRINTF("wrong size access to register!\n");
return 0;
}
switch (offset) {
case VIRTIO_MMIO_MAGIC:
return VIRT_MAGIC;
case VIRTIO_MMIO_VERSION:
return VIRT_VERSION;
case VIRTIO_MMIO_DEVICEID:
return vdev->device_id;
case VIRTIO_MMIO_VENDORID:
return VIRT_VENDOR;
case VIRTIO_MMIO_HOSTFEATURES:
if (proxy->host_features_sel) {
return 0;
}
return vdev->host_features;
case VIRTIO_MMIO_QUEUENUMMAX:
if (!virtio_queue_get_num(vdev, vdev->queue_sel)) {
return 0;
}
return VIRTQUEUE_MAX_SIZE;
case VIRTIO_MMIO_QUEUEPFN:
return virtio_queue_get_addr(vdev, vdev->queue_sel)
>> proxy->guest_page_shift;
case VIRTIO_MMIO_INTERRUPTSTATUS:
return vdev->isr;
case VIRTIO_MMIO_STATUS:
return vdev->status;
case VIRTIO_MMIO_HOSTFEATURESSEL:
case VIRTIO_MMIO_GUESTFEATURES:
case VIRTIO_MMIO_GUESTFEATURESSEL:
case VIRTIO_MMIO_GUESTPAGESIZE:
case VIRTIO_MMIO_QUEUESEL:
case VIRTIO_MMIO_QUEUENUM:
case VIRTIO_MMIO_QUEUEALIGN:
case VIRTIO_MMIO_QUEUENOTIFY:
case VIRTIO_MMIO_INTERRUPTACK:
DPRINTF("read of write-only register\n");
return 0;
default:
DPRINTF("bad register offset\n");
return 0;
}
return 0;
}
static void virtio_mmio_write(void *opaque, hwaddr offset, uint64_t value,
unsigned size)
{
VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
DPRINTF("virtio_mmio_write offset 0x%x value 0x%" PRIx64 "\n",
(int)offset, value);
if (!vdev) {
/* If no backend is present, we just make all registers
* write-ignored. This allows us to provide transports with
* no backend plugged in.
*/
return;
}
if (offset >= VIRTIO_MMIO_CONFIG) {
offset -= VIRTIO_MMIO_CONFIG;
switch (size) {
case 1:
virtio_config_writeb(vdev, offset, value);
break;
case 2:
virtio_config_writew(vdev, offset, value);
break;
case 4:
virtio_config_writel(vdev, offset, value);
break;
default:
abort();
}
return;
}
if (size != 4) {
DPRINTF("wrong size access to register!\n");
return;
}
switch (offset) {
case VIRTIO_MMIO_HOSTFEATURESSEL:
proxy->host_features_sel = value;
break;
case VIRTIO_MMIO_GUESTFEATURES:
if (!proxy->guest_features_sel) {
virtio_set_features(vdev, value);
}
break;
case VIRTIO_MMIO_GUESTFEATURESSEL:
proxy->guest_features_sel = value;
break;
case VIRTIO_MMIO_GUESTPAGESIZE:
proxy->guest_page_shift = ctz32(value);
if (proxy->guest_page_shift > 31) {
proxy->guest_page_shift = 0;
}
DPRINTF("guest page size %" PRIx64 " shift %d\n", value,
proxy->guest_page_shift);
break;
case VIRTIO_MMIO_QUEUESEL:
if (value < VIRTIO_QUEUE_MAX) {
vdev->queue_sel = value;
}
break;
case VIRTIO_MMIO_QUEUENUM:
DPRINTF("mmio_queue write %d max %d\n", (int)value, VIRTQUEUE_MAX_SIZE);
virtio_queue_set_num(vdev, vdev->queue_sel, value);
/* Note: only call this function for legacy devices */
virtio_queue_update_rings(vdev, vdev->queue_sel);
break;
case VIRTIO_MMIO_QUEUEALIGN:
/* Note: this is only valid for legacy devices */
virtio_queue_set_align(vdev, vdev->queue_sel, value);
break;
case VIRTIO_MMIO_QUEUEPFN:
if (value == 0) {
virtio_reset(vdev);
} else {
virtio_queue_set_addr(vdev, vdev->queue_sel,
value << proxy->guest_page_shift);
}
break;
case VIRTIO_MMIO_QUEUENOTIFY:
if (value < VIRTIO_QUEUE_MAX) {
virtio_queue_notify(vdev, value);
}
break;
case VIRTIO_MMIO_INTERRUPTACK:
vdev->isr &= ~value;
virtio_update_irq(vdev);
break;
case VIRTIO_MMIO_STATUS:
if (!(value & VIRTIO_CONFIG_S_DRIVER_OK)) {
virtio_mmio_stop_ioeventfd(proxy);
}
virtio_set_status(vdev, value & 0xff);
if (value & VIRTIO_CONFIG_S_DRIVER_OK) {
virtio_mmio_start_ioeventfd(proxy);
}
if (vdev->status == 0) {
virtio_reset(vdev);
}
break;
case VIRTIO_MMIO_MAGIC:
case VIRTIO_MMIO_VERSION:
case VIRTIO_MMIO_DEVICEID:
case VIRTIO_MMIO_VENDORID:
case VIRTIO_MMIO_HOSTFEATURES:
case VIRTIO_MMIO_QUEUENUMMAX:
case VIRTIO_MMIO_INTERRUPTSTATUS:
DPRINTF("write to readonly register\n");
break;
default:
DPRINTF("bad register offset\n");
}
}
static const MemoryRegionOps virtio_mem_ops = {
.read = virtio_mmio_read,
.write = virtio_mmio_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void virtio_mmio_update_irq(DeviceState *opaque, uint16_t vector)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
int level;
if (!vdev) {
return;
}
level = (vdev->isr != 0);
DPRINTF("virtio_mmio setting IRQ %d\n", level);
qemu_set_irq(proxy->irq, level);
}
static int virtio_mmio_load_config(DeviceState *opaque, QEMUFile *f)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
proxy->host_features_sel = qemu_get_be32(f);
proxy->guest_features_sel = qemu_get_be32(f);
proxy->guest_page_shift = qemu_get_be32(f);
return 0;
}
static void virtio_mmio_save_config(DeviceState *opaque, QEMUFile *f)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
qemu_put_be32(f, proxy->host_features_sel);
qemu_put_be32(f, proxy->guest_features_sel);
qemu_put_be32(f, proxy->guest_page_shift);
}
static void virtio_mmio_reset(DeviceState *d)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
virtio_mmio_stop_ioeventfd(proxy);
virtio_bus_reset(&proxy->bus);
proxy->host_features_sel = 0;
proxy->guest_features_sel = 0;
proxy->guest_page_shift = 0;
}
static int virtio_mmio_set_guest_notifier(DeviceState *d, int n, bool assign,
bool with_irqfd)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
VirtQueue *vq = virtio_get_queue(vdev, n);
EventNotifier *notifier = virtio_queue_get_guest_notifier(vq);
if (assign) {
int r = event_notifier_init(notifier, 0);
if (r < 0) {
return r;
}
virtio_queue_set_guest_notifier_fd_handler(vq, true, with_irqfd);
} else {
virtio_queue_set_guest_notifier_fd_handler(vq, false, with_irqfd);
event_notifier_cleanup(notifier);
}
if (vdc->guest_notifier_mask) {
vdc->guest_notifier_mask(vdev, n, !assign);
}
return 0;
}
static int virtio_mmio_set_guest_notifiers(DeviceState *d, int nvqs,
bool assign)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
/* TODO: need to check if kvm-arm supports irqfd */
bool with_irqfd = false;
int r, n;
nvqs = MIN(nvqs, VIRTIO_QUEUE_MAX);
for (n = 0; n < nvqs; n++) {
if (!virtio_queue_get_num(vdev, n)) {
break;
}
r = virtio_mmio_set_guest_notifier(d, n, assign, with_irqfd);
if (r < 0) {
goto assign_error;
}
}
return 0;
assign_error:
/* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */
assert(assign);
while (--n >= 0) {
virtio_mmio_set_guest_notifier(d, n, !assign, false);
}
return r;
}
static int virtio_mmio_set_host_notifier(DeviceState *opaque, int n,
bool assign)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
/* Stop using ioeventfd for virtqueue kick if the device starts using host
* notifiers. This makes it easy to avoid stepping on each others' toes.
*/
proxy->ioeventfd_disabled = assign;
if (assign) {
virtio_mmio_stop_ioeventfd(proxy);
}
/* We don't need to start here: it's not needed because backend
* currently only stops on status change away from ok,
* reset, vmstop and such. If we do add code to start here,
* need to check vmstate, device state etc. */
return virtio_mmio_set_host_notifier_internal(proxy, n, assign, false);
}
/* virtio-mmio device */
static void virtio_mmio_realizefn(DeviceState *d, Error **errp)
{
VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
SysBusDevice *sbd = SYS_BUS_DEVICE(d);
qbus_create_inplace(&proxy->bus, sizeof(proxy->bus), TYPE_VIRTIO_MMIO_BUS,
d, NULL);
sysbus_init_irq(sbd, &proxy->irq);
memory_region_init_io(&proxy->iomem, OBJECT(d), &virtio_mem_ops, proxy,
TYPE_VIRTIO_MMIO, 0x200);
sysbus_init_mmio(sbd, &proxy->iomem);
}
static void virtio_mmio_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = virtio_mmio_realizefn;
dc->reset = virtio_mmio_reset;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}
static const TypeInfo virtio_mmio_info = {
.name = TYPE_VIRTIO_MMIO,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(VirtIOMMIOProxy),
.class_init = virtio_mmio_class_init,
};
/* virtio-mmio-bus. */
static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data)
{
BusClass *bus_class = BUS_CLASS(klass);
VirtioBusClass *k = VIRTIO_BUS_CLASS(klass);
k->notify = virtio_mmio_update_irq;
k->save_config = virtio_mmio_save_config;
k->load_config = virtio_mmio_load_config;
k->set_host_notifier = virtio_mmio_set_host_notifier;
k->set_guest_notifiers = virtio_mmio_set_guest_notifiers;
k->has_variable_vring_alignment = true;
bus_class->max_dev = 1;
}
static const TypeInfo virtio_mmio_bus_info = {
.name = TYPE_VIRTIO_MMIO_BUS,
.parent = TYPE_VIRTIO_BUS,
.instance_size = sizeof(VirtioBusState),
.class_init = virtio_mmio_bus_class_init,
};
static void virtio_mmio_register_types(void)
{
type_register_static(&virtio_mmio_bus_info);
type_register_static(&virtio_mmio_info);
}
type_init(virtio_mmio_register_types)
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