vhost-vdpa: Do not send empty IOTLB update batches
With the introduction of the batch hinting, meaningless batches can be created with no IOTLB updates if the memory region was skipped by vhost_vdpa_listener_skipped_section. This is the case of host notifiers memory regions, device un/realize, and others. This causes the vdpa device to receive dma mapping settings with no changes, a possibly expensive operation for nothing. To avoid that, VHOST_IOTLB_BATCH_BEGIN hint is delayed until we have a meaningful (not skipped section) mapping or unmapping operation, and VHOST_IOTLB_BATCH_END is not written unless at least one of _UPDATE / _INVALIDATE has been issued. v3: * Use a bool instead of a counter avoiding potential number wrapping * Fix bad check on _commit * Move VHOST_BACKEND_F_IOTLB_BATCH check to vhost_vdpa_iotlb_batch_begin_once v2 (from RFC): * Rename misleading name * Abstract start batching function for listener_add/del Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Message-Id: <20210812140933.226288-1-eperezma@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
parent
8880cc4362
commit
e6db5df7e2
|
@ -89,19 +89,13 @@ static int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova,
|
||||||
return ret;
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
static void vhost_vdpa_listener_begin(MemoryListener *listener)
|
static void vhost_vdpa_listener_begin_batch(struct vhost_vdpa *v)
|
||||||
{
|
{
|
||||||
struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
|
|
||||||
struct vhost_dev *dev = v->dev;
|
|
||||||
struct vhost_msg_v2 msg = {};
|
|
||||||
int fd = v->device_fd;
|
int fd = v->device_fd;
|
||||||
|
struct vhost_msg_v2 msg = {
|
||||||
if (!(dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))) {
|
.type = v->msg_type,
|
||||||
return;
|
.iotlb.type = VHOST_IOTLB_BATCH_BEGIN,
|
||||||
}
|
};
|
||||||
|
|
||||||
msg.type = v->msg_type;
|
|
||||||
msg.iotlb.type = VHOST_IOTLB_BATCH_BEGIN;
|
|
||||||
|
|
||||||
if (write(fd, &msg, sizeof(msg)) != sizeof(msg)) {
|
if (write(fd, &msg, sizeof(msg)) != sizeof(msg)) {
|
||||||
error_report("failed to write, fd=%d, errno=%d (%s)",
|
error_report("failed to write, fd=%d, errno=%d (%s)",
|
||||||
|
@ -109,6 +103,16 @@ static void vhost_vdpa_listener_begin(MemoryListener *listener)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static void vhost_vdpa_iotlb_batch_begin_once(struct vhost_vdpa *v)
|
||||||
|
{
|
||||||
|
if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH) &&
|
||||||
|
!v->iotlb_batch_begin_sent) {
|
||||||
|
vhost_vdpa_listener_begin_batch(v);
|
||||||
|
}
|
||||||
|
|
||||||
|
v->iotlb_batch_begin_sent = true;
|
||||||
|
}
|
||||||
|
|
||||||
static void vhost_vdpa_listener_commit(MemoryListener *listener)
|
static void vhost_vdpa_listener_commit(MemoryListener *listener)
|
||||||
{
|
{
|
||||||
struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
|
struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
|
||||||
|
@ -120,6 +124,10 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener)
|
||||||
return;
|
return;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
if (!v->iotlb_batch_begin_sent) {
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
msg.type = v->msg_type;
|
msg.type = v->msg_type;
|
||||||
msg.iotlb.type = VHOST_IOTLB_BATCH_END;
|
msg.iotlb.type = VHOST_IOTLB_BATCH_END;
|
||||||
|
|
||||||
|
@ -127,6 +135,8 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener)
|
||||||
error_report("failed to write, fd=%d, errno=%d (%s)",
|
error_report("failed to write, fd=%d, errno=%d (%s)",
|
||||||
fd, errno, strerror(errno));
|
fd, errno, strerror(errno));
|
||||||
}
|
}
|
||||||
|
|
||||||
|
v->iotlb_batch_begin_sent = false;
|
||||||
}
|
}
|
||||||
|
|
||||||
static void vhost_vdpa_listener_region_add(MemoryListener *listener,
|
static void vhost_vdpa_listener_region_add(MemoryListener *listener,
|
||||||
|
@ -170,6 +180,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
|
||||||
|
|
||||||
llsize = int128_sub(llend, int128_make64(iova));
|
llsize = int128_sub(llend, int128_make64(iova));
|
||||||
|
|
||||||
|
vhost_vdpa_iotlb_batch_begin_once(v);
|
||||||
ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize),
|
ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize),
|
||||||
vaddr, section->readonly);
|
vaddr, section->readonly);
|
||||||
if (ret) {
|
if (ret) {
|
||||||
|
@ -221,6 +232,7 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
|
||||||
|
|
||||||
llsize = int128_sub(llend, int128_make64(iova));
|
llsize = int128_sub(llend, int128_make64(iova));
|
||||||
|
|
||||||
|
vhost_vdpa_iotlb_batch_begin_once(v);
|
||||||
ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize));
|
ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize));
|
||||||
if (ret) {
|
if (ret) {
|
||||||
error_report("vhost_vdpa dma unmap error!");
|
error_report("vhost_vdpa dma unmap error!");
|
||||||
|
@ -234,7 +246,6 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
|
||||||
* depends on the addnop().
|
* depends on the addnop().
|
||||||
*/
|
*/
|
||||||
static const MemoryListener vhost_vdpa_memory_listener = {
|
static const MemoryListener vhost_vdpa_memory_listener = {
|
||||||
.begin = vhost_vdpa_listener_begin,
|
|
||||||
.commit = vhost_vdpa_listener_commit,
|
.commit = vhost_vdpa_listener_commit,
|
||||||
.region_add = vhost_vdpa_listener_region_add,
|
.region_add = vhost_vdpa_listener_region_add,
|
||||||
.region_del = vhost_vdpa_listener_region_del,
|
.region_del = vhost_vdpa_listener_region_del,
|
||||||
|
|
|
@ -22,6 +22,7 @@ typedef struct VhostVDPAHostNotifier {
|
||||||
typedef struct vhost_vdpa {
|
typedef struct vhost_vdpa {
|
||||||
int device_fd;
|
int device_fd;
|
||||||
uint32_t msg_type;
|
uint32_t msg_type;
|
||||||
|
bool iotlb_batch_begin_sent;
|
||||||
MemoryListener listener;
|
MemoryListener listener;
|
||||||
struct vhost_dev *dev;
|
struct vhost_dev *dev;
|
||||||
VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
|
VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
|
||||||
|
|
Loading…
Reference in a new issue