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qemu/hw/vhost.c

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/*
* vhost support
*
* Copyright Red Hat, Inc. 2010
*
* Authors:
* Michael S. Tsirkin <mst@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*/
#include <sys/ioctl.h>
#include "vhost.h"
#include "hw/hw.h"
#include "range.h"
#include <linux/vhost.h>
static void vhost_dev_sync_region(struct vhost_dev *dev,
uint64_t mfirst, uint64_t mlast,
uint64_t rfirst, uint64_t rlast)
{
uint64_t start = MAX(mfirst, rfirst);
uint64_t end = MIN(mlast, rlast);
vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
assert(end / VHOST_LOG_CHUNK < dev->log_size);
assert(start / VHOST_LOG_CHUNK < dev->log_size);
if (end < start) {
return;
}
for (;from < to; ++from) {
vhost_log_chunk_t log;
int bit;
/* We first check with non-atomic: much cheaper,
* and we expect non-dirty to be the common case. */
if (!*from) {
addr += VHOST_LOG_CHUNK;
continue;
}
/* Data must be read atomically. We don't really
* need the barrier semantics of __sync
* builtins, but it's easier to use them than
* roll our own. */
log = __sync_fetch_and_and(from, 0);
while ((bit = sizeof(log) > sizeof(int) ?
ffsll(log) : ffs(log))) {
ram_addr_t ram_addr;
bit -= 1;
ram_addr = cpu_get_physical_page_desc(addr + bit * VHOST_LOG_PAGE);
cpu_physical_memory_set_dirty(ram_addr);
log &= ~(0x1ull << bit);
}
addr += VHOST_LOG_CHUNK;
}
}
static int vhost_client_sync_dirty_bitmap(CPUPhysMemoryClient *client,
target_phys_addr_t start_addr,
target_phys_addr_t end_addr)
{
struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
int i;
if (!dev->log_enabled || !dev->started) {
return 0;
}
for (i = 0; i < dev->mem->nregions; ++i) {
struct vhost_memory_region *reg = dev->mem->regions + i;
vhost_dev_sync_region(dev, start_addr, end_addr,
reg->guest_phys_addr,
range_get_last(reg->guest_phys_addr,
reg->memory_size));
}
for (i = 0; i < dev->nvqs; ++i) {
struct vhost_virtqueue *vq = dev->vqs + i;
vhost_dev_sync_region(dev, start_addr, end_addr, vq->used_phys,
range_get_last(vq->used_phys, vq->used_size));
}
return 0;
}
/* Assign/unassign. Keep an unsorted array of non-overlapping
* memory regions in dev->mem. */
static void vhost_dev_unassign_memory(struct vhost_dev *dev,
uint64_t start_addr,
uint64_t size)
{
int from, to, n = dev->mem->nregions;
/* Track overlapping/split regions for sanity checking. */
int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0;
for (from = 0, to = 0; from < n; ++from, ++to) {
struct vhost_memory_region *reg = dev->mem->regions + to;
uint64_t reglast;
uint64_t memlast;
uint64_t change;
/* clone old region */
if (to != from) {
memcpy(reg, dev->mem->regions + from, sizeof *reg);
}
/* No overlap is simple */
if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size,
start_addr, size)) {
continue;
}
/* Split only happens if supplied region
* is in the middle of an existing one. Thus it can not
* overlap with any other existing region. */
assert(!split);
reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
memlast = range_get_last(start_addr, size);
/* Remove whole region */
if (start_addr <= reg->guest_phys_addr && memlast >= reglast) {
--dev->mem->nregions;
--to;
assert(to >= 0);
++overlap_middle;
continue;
}
/* Shrink region */
if (memlast >= reglast) {
reg->memory_size = start_addr - reg->guest_phys_addr;
assert(reg->memory_size);
assert(!overlap_end);
++overlap_end;
continue;
}
/* Shift region */
if (start_addr <= reg->guest_phys_addr) {
change = memlast + 1 - reg->guest_phys_addr;
reg->memory_size -= change;
reg->guest_phys_addr += change;
reg->userspace_addr += change;
assert(reg->memory_size);
assert(!overlap_start);
++overlap_start;
continue;
}
/* This only happens if supplied region
* is in the middle of an existing one. Thus it can not
* overlap with any other existing region. */
assert(!overlap_start);
assert(!overlap_end);
assert(!overlap_middle);
/* Split region: shrink first part, shift second part. */
memcpy(dev->mem->regions + n, reg, sizeof *reg);
reg->memory_size = start_addr - reg->guest_phys_addr;
assert(reg->memory_size);
change = memlast + 1 - reg->guest_phys_addr;
reg = dev->mem->regions + n;
reg->memory_size -= change;
assert(reg->memory_size);
reg->guest_phys_addr += change;
reg->userspace_addr += change;
/* Never add more than 1 region */
assert(dev->mem->nregions == n);
++dev->mem->nregions;
++split;
}
}
/* Called after unassign, so no regions overlap the given range. */
static void vhost_dev_assign_memory(struct vhost_dev *dev,
uint64_t start_addr,
uint64_t size,
uint64_t uaddr)
{
int from, to;
struct vhost_memory_region *merged = NULL;
for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) {
struct vhost_memory_region *reg = dev->mem->regions + to;
uint64_t prlast, urlast;
uint64_t pmlast, umlast;
uint64_t s, e, u;
/* clone old region */
if (to != from) {
memcpy(reg, dev->mem->regions + from, sizeof *reg);
}
prlast = range_get_last(reg->guest_phys_addr, reg->memory_size);
pmlast = range_get_last(start_addr, size);
urlast = range_get_last(reg->userspace_addr, reg->memory_size);
umlast = range_get_last(uaddr, size);
/* check for overlapping regions: should never happen. */
assert(prlast < start_addr || pmlast < reg->guest_phys_addr);
/* Not an adjacent or overlapping region - do not merge. */
if ((prlast + 1 != start_addr || urlast + 1 != uaddr) &&
(pmlast + 1 != reg->guest_phys_addr ||
umlast + 1 != reg->userspace_addr)) {
continue;
}
if (merged) {
--to;
assert(to >= 0);
} else {
merged = reg;
}
u = MIN(uaddr, reg->userspace_addr);
s = MIN(start_addr, reg->guest_phys_addr);
e = MAX(pmlast, prlast);
uaddr = merged->userspace_addr = u;
start_addr = merged->guest_phys_addr = s;
size = merged->memory_size = e - s + 1;
assert(merged->memory_size);
}
if (!merged) {
struct vhost_memory_region *reg = dev->mem->regions + to;
memset(reg, 0, sizeof *reg);
reg->memory_size = size;
assert(reg->memory_size);
reg->guest_phys_addr = start_addr;
reg->userspace_addr = uaddr;
++to;
}
assert(to <= dev->mem->nregions + 1);
dev->mem->nregions = to;
}
static uint64_t vhost_get_log_size(struct vhost_dev *dev)
{
uint64_t log_size = 0;
int i;
for (i = 0; i < dev->mem->nregions; ++i) {
struct vhost_memory_region *reg = dev->mem->regions + i;
uint64_t last = range_get_last(reg->guest_phys_addr,
reg->memory_size);
log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
}
for (i = 0; i < dev->nvqs; ++i) {
struct vhost_virtqueue *vq = dev->vqs + i;
uint64_t last = vq->used_phys + vq->used_size - 1;
log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
}
return log_size;
}
static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
{
vhost_log_chunk_t *log;
uint64_t log_base;
int r;
if (size) {
log = qemu_mallocz(size * sizeof *log);
} else {
log = NULL;
}
log_base = (uint64_t)(unsigned long)log;
r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
assert(r >= 0);
vhost_client_sync_dirty_bitmap(&dev->client, 0,
(target_phys_addr_t)~0x0ull);
if (dev->log) {
qemu_free(dev->log);
}
dev->log = log;
dev->log_size = size;
}
static int vhost_verify_ring_mappings(struct vhost_dev *dev,
uint64_t start_addr,
uint64_t size)
{
int i;
for (i = 0; i < dev->nvqs; ++i) {
struct vhost_virtqueue *vq = dev->vqs + i;
target_phys_addr_t l;
void *p;
if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {
continue;
}
l = vq->ring_size;
p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
if (!p || l != vq->ring_size) {
fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
return -ENOMEM;
}
if (p != vq->ring) {
fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
return -EBUSY;
}
cpu_physical_memory_unmap(p, l, 0, 0);
}
return 0;
}
static void vhost_client_set_memory(CPUPhysMemoryClient *client,
target_phys_addr_t start_addr,
ram_addr_t size,
ram_addr_t phys_offset)
{
struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
ram_addr_t flags = phys_offset & ~TARGET_PAGE_MASK;
int s = offsetof(struct vhost_memory, regions) +
(dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
uint64_t log_size;
int r;
dev->mem = qemu_realloc(dev->mem, s);
assert(size);
vhost_dev_unassign_memory(dev, start_addr, size);
if (flags == IO_MEM_RAM) {
/* Add given mapping, merging adjacent regions if any */
vhost_dev_assign_memory(dev, start_addr, size,
(uintptr_t)qemu_get_ram_ptr(phys_offset));
} else {
/* Remove old mapping for this memory, if any. */
vhost_dev_unassign_memory(dev, start_addr, size);
}
if (!dev->started) {
return;
}
if (dev->started) {
r = vhost_verify_ring_mappings(dev, start_addr, size);
assert(r >= 0);
}
if (!dev->log_enabled) {
r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
assert(r >= 0);
return;
}
log_size = vhost_get_log_size(dev);
/* We allocate an extra 4K bytes to log,
* to reduce the * number of reallocations. */
#define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
/* To log more, must increase log size before table update. */
if (dev->log_size < log_size) {
vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
}
r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
assert(r >= 0);
/* To log less, can only decrease log size after table update. */
if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
vhost_dev_log_resize(dev, log_size);
}
}
static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
unsigned idx, bool enable_log)
{
struct vhost_vring_addr addr = {
.index = idx,
.desc_user_addr = (uint64_t)(unsigned long)vq->desc,
.avail_user_addr = (uint64_t)(unsigned long)vq->avail,
.used_user_addr = (uint64_t)(unsigned long)vq->used,
.log_guest_addr = vq->used_phys,
.flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
};
int r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
if (r < 0) {
return -errno;
}
return 0;
}
static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
{
uint64_t features = dev->acked_features;
int r;
if (enable_log) {
features |= 0x1 << VHOST_F_LOG_ALL;
}
r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
return r < 0 ? -errno : 0;
}
static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
{
int r, t, i;
r = vhost_dev_set_features(dev, enable_log);
if (r < 0) {
goto err_features;
}
for (i = 0; i < dev->nvqs; ++i) {
r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
enable_log);
if (r < 0) {
goto err_vq;
}
}
return 0;
err_vq:
for (; i >= 0; --i) {
t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
dev->log_enabled);
assert(t >= 0);
}
t = vhost_dev_set_features(dev, dev->log_enabled);
assert(t >= 0);
err_features:
return r;
}
static int vhost_client_migration_log(CPUPhysMemoryClient *client,
int enable)
{
struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
int r;
if (!!enable == dev->log_enabled) {
return 0;
}
if (!dev->started) {
dev->log_enabled = enable;
return 0;
}
if (!enable) {
r = vhost_dev_set_log(dev, false);
if (r < 0) {
return r;
}
if (dev->log) {
qemu_free(dev->log);
}
dev->log = NULL;
dev->log_size = 0;
} else {
vhost_dev_log_resize(dev, vhost_get_log_size(dev));
r = vhost_dev_set_log(dev, true);
if (r < 0) {
return r;
}
}
dev->log_enabled = enable;
return 0;
}
static int vhost_virtqueue_init(struct vhost_dev *dev,
struct VirtIODevice *vdev,
struct vhost_virtqueue *vq,
unsigned idx)
{
target_phys_addr_t s, l, a;
int r;
struct vhost_vring_file file = {
.index = idx,
};
struct vhost_vring_state state = {
.index = idx,
};
struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
if (!vdev->binding->set_host_notifier) {
fprintf(stderr, "binding does not support host notifiers\n");
return -ENOSYS;
}
vq->num = state.num = virtio_queue_get_num(vdev, idx);
r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
if (r) {
return -errno;
}
state.num = virtio_queue_get_last_avail_idx(vdev, idx);
r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
if (r) {
return -errno;
}
s = l = virtio_queue_get_desc_size(vdev, idx);
a = virtio_queue_get_desc_addr(vdev, idx);
vq->desc = cpu_physical_memory_map(a, &l, 0);
if (!vq->desc || l != s) {
r = -ENOMEM;
goto fail_alloc_desc;
}
s = l = virtio_queue_get_avail_size(vdev, idx);
a = virtio_queue_get_avail_addr(vdev, idx);
vq->avail = cpu_physical_memory_map(a, &l, 0);
if (!vq->avail || l != s) {
r = -ENOMEM;
goto fail_alloc_avail;
}
vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
vq->used = cpu_physical_memory_map(a, &l, 1);
if (!vq->used || l != s) {
r = -ENOMEM;
goto fail_alloc_used;
}
vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
vq->ring = cpu_physical_memory_map(a, &l, 1);
if (!vq->ring || l != s) {
r = -ENOMEM;
goto fail_alloc_ring;
}
r = vhost_virtqueue_set_addr(dev, vq, idx, dev->log_enabled);
if (r < 0) {
r = -errno;
goto fail_alloc;
}
r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, true);
if (r < 0) {
fprintf(stderr, "Error binding host notifier: %d\n", -r);
goto fail_host_notifier;
}
file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
if (r) {
r = -errno;
goto fail_kick;
}
file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
if (r) {
r = -errno;
goto fail_call;
}
return 0;
fail_call:
fail_kick:
vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
fail_host_notifier:
fail_alloc:
cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
0, 0);
fail_alloc_ring:
cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
0, 0);
fail_alloc_used:
cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
0, 0);
fail_alloc_avail:
cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
0, 0);
fail_alloc_desc:
return r;
}
static void vhost_virtqueue_cleanup(struct vhost_dev *dev,
struct VirtIODevice *vdev,
struct vhost_virtqueue *vq,
unsigned idx)
{
struct vhost_vring_state state = {
.index = idx,
};
int r;
r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
if (r < 0) {
fprintf(stderr, "vhost VQ %d host cleanup failed: %d\n", idx, r);
fflush(stderr);
}
assert (r >= 0);
r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);
if (r < 0) {
fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
fflush(stderr);
}
virtio_queue_set_last_avail_idx(vdev, idx, state.num);
assert (r >= 0);
cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
0, virtio_queue_get_ring_size(vdev, idx));
cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
1, virtio_queue_get_used_size(vdev, idx));
cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
0, virtio_queue_get_avail_size(vdev, idx));
cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
0, virtio_queue_get_desc_size(vdev, idx));
}
int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
{
uint64_t features;
int r;
if (devfd >= 0) {
hdev->control = devfd;
} else {
hdev->control = open("/dev/vhost-net", O_RDWR);
if (hdev->control < 0) {
return -errno;
}
}
r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
if (r < 0) {
goto fail;
}
r = ioctl(hdev->control, VHOST_GET_FEATURES, &features);
if (r < 0) {
goto fail;
}
hdev->features = features;
hdev->client.set_memory = vhost_client_set_memory;
hdev->client.sync_dirty_bitmap = vhost_client_sync_dirty_bitmap;
hdev->client.migration_log = vhost_client_migration_log;
hdev->client.log_start = NULL;
hdev->client.log_stop = NULL;
hdev->mem = qemu_mallocz(offsetof(struct vhost_memory, regions));
hdev->log = NULL;
hdev->log_size = 0;
hdev->log_enabled = false;
hdev->started = false;
cpu_register_phys_memory_client(&hdev->client);
hdev->force = force;
return 0;
fail:
r = -errno;
close(hdev->control);
return r;
}
void vhost_dev_cleanup(struct vhost_dev *hdev)
{
cpu_unregister_phys_memory_client(&hdev->client);
qemu_free(hdev->mem);
close(hdev->control);
}
bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev)
{
return !vdev->binding->query_guest_notifiers ||
vdev->binding->query_guest_notifiers(vdev->binding_opaque) ||
hdev->force;
}
int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
{
int i, r;
if (!vdev->binding->set_guest_notifiers) {
fprintf(stderr, "binding does not support guest notifiers\n");
r = -ENOSYS;
goto fail;
}
r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, true);
if (r < 0) {
fprintf(stderr, "Error binding guest notifier: %d\n", -r);
goto fail_notifiers;
}
r = vhost_dev_set_features(hdev, hdev->log_enabled);
if (r < 0) {
goto fail_features;
}
r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
if (r < 0) {
r = -errno;
goto fail_mem;
}
for (i = 0; i < hdev->nvqs; ++i) {
r = vhost_virtqueue_init(hdev,
vdev,
hdev->vqs + i,
i);
if (r < 0) {
goto fail_vq;
}
}
if (hdev->log_enabled) {
hdev->log_size = vhost_get_log_size(hdev);
hdev->log = hdev->log_size ?
qemu_mallocz(hdev->log_size * sizeof *hdev->log) : NULL;
r = ioctl(hdev->control, VHOST_SET_LOG_BASE,
(uint64_t)(unsigned long)hdev->log);
if (r < 0) {
r = -errno;
goto fail_log;
}
}
hdev->started = true;
return 0;
fail_log:
fail_vq:
while (--i >= 0) {
vhost_virtqueue_cleanup(hdev,
vdev,
hdev->vqs + i,
i);
}
fail_mem:
fail_features:
vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
fail_notifiers:
fail:
return r;
}
void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
{
int i, r;
for (i = 0; i < hdev->nvqs; ++i) {
vhost_virtqueue_cleanup(hdev,
vdev,
hdev->vqs + i,
i);
}
vhost_client_sync_dirty_bitmap(&hdev->client, 0,
(target_phys_addr_t)~0x0ull);
r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
if (r < 0) {
fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
fflush(stderr);
}
assert (r >= 0);
hdev->started = false;
qemu_free(hdev->log);
hdev->log_size = 0;
}
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