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virtio: use VRingMemoryRegionCaches for avail and used rings

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The virtio-net change is necessary because it uses virtqueue_fill
and virtqueue_flush instead of the more convenient virtqueue_push.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-01-27 16:40:20 +01:00 committed by Michael S. Tsirkin
parent ca0176ad83
commit 97cd965c07
2 changed files with 109 additions and 37 deletions
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14
hw/net/virtio-net.c
View File

@ -1130,7 +1130,8 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
return 0;
}
static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf, size_t size)
static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
size_t size)
{
VirtIONet *n = qemu_get_nic_opaque(nc);
VirtIONetQueue *q = virtio_net_get_subqueue(nc);
@ -1233,6 +1234,17 @@ static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf, size_t
return size;
}
static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf,
size_t size)
{
ssize_t r;
rcu_read_lock();
r = virtio_net_receive_rcu(nc, buf, size);
rcu_read_unlock();
return r;
}
static int32_t virtio_net_flush_tx(VirtIONetQueue *q);
static void virtio_net_tx_complete(NetClientState *nc, ssize_t len)

132
hw/virtio/virtio.c
View File

@ -173,6 +173,7 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
virtio_init_region_cache(vdev, n);
}
/* Called within rcu_read_lock(). */
static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
MemoryRegionCache *cache, int i)
{
@ -184,88 +185,110 @@ static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
virtio_tswap16s(vdev, &desc->next);
}
/* Called within rcu_read_lock(). */
static inline uint16_t vring_avail_flags(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, flags);
return virtio_lduw_phys(vq->vdev, pa);
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingAvail, flags);
return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
}
/* Called within rcu_read_lock(). */
static inline uint16_t vring_avail_idx(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, idx);
vq->shadow_avail_idx = virtio_lduw_phys(vq->vdev, pa);
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingAvail, idx);
vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
return vq->shadow_avail_idx;
}
/* Called within rcu_read_lock(). */
static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
{
hwaddr pa;
pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
return virtio_lduw_phys(vq->vdev, pa);
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingAvail, ring[i]);
return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
}
/* Called within rcu_read_lock(). */
static inline uint16_t vring_get_used_event(VirtQueue *vq)
{
return vring_avail_ring(vq, vq->vring.num);
}
/* Called within rcu_read_lock(). */
static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
int i)
{
hwaddr pa;
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingUsed, ring[i]);
virtio_tswap32s(vq->vdev, &uelem->id);
virtio_tswap32s(vq->vdev, &uelem->len);
pa = vq->vring.used + offsetof(VRingUsed, ring[i]);
address_space_write(vq->vdev->dma_as, pa, MEMTXATTRS_UNSPECIFIED,
(void *)uelem, sizeof(VRingUsedElem));
address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
}
/* Called within rcu_read_lock(). */
static uint16_t vring_used_idx(VirtQueue *vq)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, idx);
return virtio_lduw_phys(vq->vdev, pa);
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingUsed, idx);
return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
}
/* Called within rcu_read_lock(). */
static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
{
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, idx);
virtio_stw_phys(vq->vdev, pa, val);
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
hwaddr pa = offsetof(VRingUsed, idx);
virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
address_space_cache_invalidate(&caches->used, pa, sizeof(val));
vq->used_idx = val;
}
/* Called within rcu_read_lock(). */
static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
{
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
VirtIODevice *vdev = vq->vdev;
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, flags);
virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) | mask);
hwaddr pa = offsetof(VRingUsed, flags);
uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
}
/* Called within rcu_read_lock(). */
static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
{
VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
VirtIODevice *vdev = vq->vdev;
hwaddr pa;
pa = vq->vring.used + offsetof(VRingUsed, flags);
virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask);
hwaddr pa = offsetof(VRingUsed, flags);
uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
}
/* Called within rcu_read_lock(). */
static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
{
VRingMemoryRegionCaches *caches;
hwaddr pa;
if (!vq->notification) {
return;
}
pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
virtio_stw_phys(vq->vdev, pa, val);
caches = atomic_rcu_read(&vq->vring.caches);
pa = offsetof(VRingUsed, ring[vq->vring.num]);
virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
}
void virtio_queue_set_notification(VirtQueue *vq, int enable)
{
vq->notification = enable;
rcu_read_lock();
if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vring_avail_idx(vq));
} else if (enable) {
@ -277,6 +300,7 @@ void virtio_queue_set_notification(VirtQueue *vq, int enable)
/* Expose avail event/used flags before caller checks the avail idx. */
smp_mb();
}
rcu_read_unlock();
}
int virtio_queue_ready(VirtQueue *vq)
@ -285,8 +309,9 @@ int virtio_queue_ready(VirtQueue *vq)
}
/* Fetch avail_idx from VQ memory only when we really need to know if
* guest has added some buffers. */
int virtio_queue_empty(VirtQueue *vq)
* guest has added some buffers.
* Called within rcu_read_lock(). */
static int virtio_queue_empty_rcu(VirtQueue *vq)
{
if (vq->shadow_avail_idx != vq->last_avail_idx) {
return 0;
@ -295,6 +320,20 @@ int virtio_queue_empty(VirtQueue *vq)
return vring_avail_idx(vq) == vq->last_avail_idx;
}
int virtio_queue_empty(VirtQueue *vq)
{
bool empty;
if (vq->shadow_avail_idx != vq->last_avail_idx) {
return 0;
}
rcu_read_lock();
empty = vring_avail_idx(vq) == vq->last_avail_idx;
rcu_read_unlock();
return empty;
}
static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len)
{
@ -373,6 +412,7 @@ bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
return true;
}
/* Called within rcu_read_lock(). */
void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx)
{
@ -393,6 +433,7 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
vring_used_write(vq, &uelem, idx);
}
/* Called within rcu_read_lock(). */
void virtqueue_flush(VirtQueue *vq, unsigned int count)
{
uint16_t old, new;
@ -416,10 +457,13 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len)
{
rcu_read_lock();
virtqueue_fill(vq, elem, len, 0);
virtqueue_flush(vq, 1);
rcu_read_unlock();
}
/* Called within rcu_read_lock(). */
static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
{
uint16_t num_heads = vring_avail_idx(vq) - idx;
@ -439,6 +483,7 @@ static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
return num_heads;
}
/* Called within rcu_read_lock(). */
static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
unsigned int *head)
{
@ -740,8 +785,9 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
if (unlikely(vdev->broken)) {
return NULL;
}
if (virtio_queue_empty(vq)) {
return NULL;
rcu_read_lock();
if (virtio_queue_empty_rcu(vq)) {
goto done;
}
/* Needed after virtio_queue_empty(), see comment in
* virtqueue_num_heads(). */
@ -754,11 +800,11 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
if (vq->inuse >= vq->vring.num) {
virtio_error(vdev, "Virtqueue size exceeded");
return NULL;
goto done;
}
if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
return NULL;
goto done;
}
if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
@ -767,7 +813,6 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
i = head;
rcu_read_lock();
caches = atomic_rcu_read(&vq->vring.caches);
if (caches->desc.len < max * sizeof(VRingDesc)) {
virtio_error(vdev, "Cannot map descriptor ring");
@ -1483,6 +1528,7 @@ static void virtio_set_isr(VirtIODevice *vdev, int value)
}
}
/* Called within rcu_read_lock(). */
static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
{
uint16_t old, new;
@ -1508,7 +1554,12 @@ static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
{
if (!virtio_should_notify(vdev, vq)) {
bool should_notify;
rcu_read_lock();
should_notify = virtio_should_notify(vdev, vq);
rcu_read_unlock();
if (!should_notify) {
return;
}
@ -1535,7 +1586,12 @@ void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
{
if (!virtio_should_notify(vdev, vq)) {
bool should_notify;
rcu_read_lock();
should_notify = virtio_should_notify(vdev, vq);
rcu_read_unlock();
if (!should_notify) {
return;
}
@ -1996,6 +2052,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
}
}
rcu_read_lock();
for (i = 0; i < num; i++) {
if (vdev->vq[i].vring.desc) {
uint16_t nheads;
@ -2030,6 +2087,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
}
}
}
rcu_read_unlock();
return 0;
}
@ -2156,9 +2214,11 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
{
rcu_read_lock();
if (vdev->vq[n].vring.desc) {
vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
}
rcu_read_unlock();
}
void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)