Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
---
hw/virtio/vhost-sw-lm-ring.h | 3 +
hw/virtio/vhost-sw-lm-ring.c | 134 +++++++++++++++++++++++++++++++++--
hw/virtio/vhost.c | 59 ++++++++++++++-
3 files changed, 189 insertions(+), 7 deletions(-)
diff --git a/hw/virtio/vhost-sw-lm-ring.h b/hw/virtio/vhost-sw-lm-ring.h
index 86dc081b93..29d21feaf4 100644
--- a/hw/virtio/vhost-sw-lm-ring.h
+++ b/hw/virtio/vhost-sw-lm-ring.h
@@ -18,6 +18,9 @@
typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
bool vhost_vring_kick(VhostShadowVirtqueue *vq);
+int vhost_vring_add(VhostShadowVirtqueue *vq, VirtQueueElement *elem);
+void vhost_vring_write_addr(const VhostShadowVirtqueue *vq,
+ struct vhost_vring_addr *addr);
VhostShadowVirtqueue *vhost_sw_lm_shadow_vq(struct vhost_dev *dev, int idx);
diff --git a/hw/virtio/vhost-sw-lm-ring.c b/hw/virtio/vhost-sw-lm-ring.c
index cd7b5ba772..aed005c2d9 100644
--- a/hw/virtio/vhost-sw-lm-ring.c
+++ b/hw/virtio/vhost-sw-lm-ring.c
@@ -9,6 +9,7 @@
#include "hw/virtio/vhost-sw-lm-ring.h"
#include "hw/virtio/vhost.h"
+#include "hw/virtio/virtio-access.h"
#include "standard-headers/linux/vhost_types.h"
#include "standard-headers/linux/virtio_ring.h"
@@ -19,21 +20,140 @@ typedef struct VhostShadowVirtqueue {
struct vring vring;
EventNotifier hdev_notifier;
VirtQueue *vq;
+ VirtIODevice *vdev;
+
+ /* Map for returning guest's descriptors */
+ VirtQueueElement **ring_id_maps;
+
+ /* Next head to expose to device */
+ uint16_t avail_idx_shadow;
+
+ /* Number of descriptors added since last notification */
+ uint16_t num_added;
+
+ /* Next free descriptor */
+ uint16_t free_head;
vring_desc_t descs[];
} VhostShadowVirtqueue;
-static inline bool vhost_vring_should_kick(VhostShadowVirtqueue *vq)
+static bool vhost_vring_should_kick_rcu(VhostShadowVirtqueue *vq)
{
- return virtio_queue_get_used_notify_split(vq->vq);
+ VirtIODevice *vdev = vq->vdev;
+ vq->num_added = 0;
+
+ smp_rmb();
+ return !(vq->vring.used->flags
+ & virtio_tswap16(vdev, VRING_USED_F_NO_NOTIFY));
}
+static bool vhost_vring_should_kick(VhostShadowVirtqueue *vq)
+{
+ RCU_READ_LOCK_GUARD();
+ return vhost_vring_should_kick_rcu(vq);
+}
+
+
bool vhost_vring_kick(VhostShadowVirtqueue *vq)
{
return vhost_vring_should_kick(vq) ? event_notifier_set(&vq->hdev_notifier)
: true;
}
+static void vhost_vring_write_descs(VhostShadowVirtqueue *vq,
+ const struct iovec *iovec,
+ size_t num, bool more_descs, bool write)
+{
+ uint16_t i = vq->free_head, last = vq->free_head;
+ unsigned n;
+ const VirtIODevice *vdev = vq->vdev;
+ uint16_t flags = write ? virtio_tswap16(vdev, VRING_DESC_F_WRITE) : 0;
+ vring_desc_t *descs = vq->vring.desc;
+
+ if (num == 0) {
+ return;
+ }
+
+ for (n = 0; n < num; n++) {
+ if (more_descs || (n + 1 < num)) {
+ descs[i].flags = flags | virtio_tswap16(vdev, VRING_DESC_F_NEXT);
+ } else {
+ descs[i].flags = flags;
+ }
+ descs[i].addr = virtio_tswap64(vdev, (hwaddr)iovec[n].iov_base);
+ descs[i].len = virtio_tswap32(vdev, iovec[n].iov_len);
+
+ last = i;
+ i = virtio_tswap16(vdev, descs[i].next);
+ }
+
+ vq->free_head = virtio_tswap16(vdev, descs[last].next);
+}
+
+/* virtqueue_add:
+ * @vq: The #VirtQueue
+ * @elem: The #VirtQueueElement
+ *
+ * Add an avail element to a virtqueue.
+ */
+static int vhost_vring_add_split(VhostShadowVirtqueue *vq,
+ const VirtQueueElement *elem)
+{
+ int head;
+ unsigned avail_idx;
+ const VirtIODevice *vdev;
+ vring_avail_t *avail;
+
+ RCU_READ_LOCK_GUARD();
+ vdev = vq->vdev;
+ avail = vq->vring.avail;
+
+ head = vq->free_head;
+
+ /* We need some descriptors here */
+ assert(elem->out_num || elem->in_num);
+
+ vhost_vring_write_descs(vq, elem->out_sg, elem->out_num,
+ elem->in_num > 0, false);
+ vhost_vring_write_descs(vq, elem->in_sg, elem->in_num, false, true);
+
+ /* Put entry in available array (but don't update avail->idx until they
+ * do sync). */
+ avail_idx = vq->avail_idx_shadow & (vq->vring.num - 1);
+ avail->ring[avail_idx] = virtio_tswap16(vdev, head);
+ vq->avail_idx_shadow++;
+
+ /* Expose descriptors to device */
+ smp_wmb();
+ avail->idx = virtio_tswap16(vdev, vq->avail_idx_shadow);
+
+ /* threoretically possible. Kick just in case */
+ if (unlikely(vq->num_added++ == (uint16_t)-1)) {
+ vhost_vring_kick(vq);
+ }
+
+ return head;
+}
+
+int vhost_vring_add(VhostShadowVirtqueue *vq, VirtQueueElement *elem)
+{
+ int host_head = vhost_vring_add_split(vq, elem);
+ if (vq->ring_id_maps[host_head]) {
+ g_free(vq->ring_id_maps[host_head]);
+ }
+
+ vq->ring_id_maps[host_head] = elem;
+ return 0;
+}
+
+void vhost_vring_write_addr(const VhostShadowVirtqueue *vq,
+ struct vhost_vring_addr *addr)
+{
+ addr->desc_user_addr = (uint64_t)vq->vring.desc;
+ addr->avail_user_addr = (uint64_t)vq->vring.avail;
+ addr->used_user_addr = (uint64_t)vq->vring.used;
+}
+
VhostShadowVirtqueue *vhost_sw_lm_shadow_vq(struct vhost_dev *dev, int idx)
{
struct vhost_vring_file file = {
@@ -43,9 +163,11 @@ VhostShadowVirtqueue *vhost_sw_lm_shadow_vq(struct vhost_dev *dev, int idx)
unsigned num = virtio_queue_get_num(dev->vdev, idx);
size_t ring_size = vring_size(num, VRING_DESC_ALIGN_SIZE);
VhostShadowVirtqueue *svq;
- int r;
+ int r, i;
svq = g_malloc0(sizeof(*svq) + ring_size);
+ svq->ring_id_maps = g_new0(VirtQueueElement *, num);
+ svq->vdev = dev->vdev;
svq->vq = vq;
r = event_notifier_init(&svq->hdev_notifier, 0);
@@ -55,8 +177,9 @@ VhostShadowVirtqueue *vhost_sw_lm_shadow_vq(struct vhost_dev *dev, int idx)
r = dev->vhost_ops->vhost_set_vring_kick(dev, &file);
assert(r == 0);
- vhost_virtqueue_mask(dev, dev->vdev, idx, true);
- vhost_virtqueue_pending(dev, idx);
+ vring_init(&svq->vring, num, svq->descs, VRING_DESC_ALIGN_SIZE);
+ for (i = 0; i < num - 1; i++)
+ svq->descs[i].next = virtio_tswap16(dev->vdev, i + 1);
return svq;
}
@@ -64,5 +187,6 @@ VhostShadowVirtqueue *vhost_sw_lm_shadow_vq(struct vhost_dev *dev, int idx)
void vhost_sw_lm_shadow_vq_free(VhostShadowVirtqueue *vq)
{
event_notifier_cleanup(&vq->hdev_notifier);
+ g_free(vq->ring_id_maps);
g_free(vq);
}
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 9352c56bfa..304e0baa61 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -956,8 +956,34 @@ static void handle_sw_lm_vq(VirtIODevice *vdev, VirtQueue *vq)
uint16_t idx = virtio_get_queue_index(vq);
VhostShadowVirtqueue *svq = hdev->sw_lm_shadow_vq[idx];
+ VirtQueueElement *elem;
- vhost_vring_kick(svq);
+ /*
+ * Make available all buffers as possible.
+ */
+ do {
+ if (virtio_queue_get_notification(vq)) {
+ virtio_queue_set_notification(vq, false);
+ }
+
+ while (true) {
+ int r;
+ if (virtio_queue_full(vq)) {
+ break;
+ }
+
+ elem = virtqueue_pop(vq, sizeof(*elem));
+ if (!elem) {
+ break;
+ }
+
+ r = vhost_vring_add(svq, elem);
+ assert(r >= 0);
+ vhost_vring_kick(svq);
+ }
+
+ virtio_queue_set_notification(vq, true);
+ } while(!virtio_queue_empty(vq));
}
static void vhost_handle_call(EventNotifier *n)
@@ -975,6 +1001,11 @@ static void vhost_handle_call(EventNotifier *n)
}
}
+static void vhost_virtqueue_stop(struct vhost_dev *dev,
+ struct VirtIODevice *vdev,
+ struct vhost_virtqueue *vq,
+ unsigned idx);
+
static int vhost_sw_live_migration_stop(struct vhost_dev *dev)
{
int idx;
@@ -991,17 +1022,41 @@ static int vhost_sw_live_migration_stop(struct vhost_dev *dev)
static int vhost_sw_live_migration_start(struct vhost_dev *dev)
{
- int idx;
+ int idx, r;
+
+ assert(dev->vhost_ops->vhost_set_vring_enable);
+ dev->vhost_ops->vhost_set_vring_enable(dev, false);
for (idx = 0; idx < dev->nvqs; ++idx) {
struct vhost_virtqueue *vq = &dev->vqs[idx];
+ struct vhost_vring_addr addr = {
+ .index = idx,
+ };
+ struct vhost_vring_state s = {
+ .index = idx,
+ };
+
+ vhost_virtqueue_stop(dev, dev->vdev, &dev->vqs[idx], idx);
dev->sw_lm_shadow_vq[idx] = vhost_sw_lm_shadow_vq(dev, idx);
event_notifier_set_handler(&vq->masked_notifier, vhost_handle_call);
+
+ vhost_vring_write_addr(dev->sw_lm_shadow_vq[idx], &addr);
+ r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
+ assert(r == 0);
+
+ r = dev->vhost_ops->vhost_set_vring_base(dev, &s);
+ assert(r == 0);
}
+ dev->vhost_ops->vhost_set_vring_enable(dev, true);
vhost_dev_disable_notifiers(dev, dev->vdev);
+ for (idx = 0; idx < dev->nvqs; ++idx) {
+ vhost_virtqueue_mask(dev, dev->vdev, idx, true);
+ vhost_virtqueue_pending(dev, idx);
+ }
+
return 0;
}
--
2.18.4
