From: Maxime Coquelin <maxime.coque...@redhat.com>
In case of backend crash, it is not possible to restore internal
avail index from the backend value as vhost_get_vring_base
callback fails.
This patch provides a new interface to restore internal avail index
from the vring used index, as done by some vhost-user backend on
reconnection.
Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
(cherry picked from commit 2d4ba6cc741df15df6fbb4feaa706a02e103083a)
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
hw/virtio/virtio.c | 10 ++++++++++
include/hw/virtio/virtio.h | 1 +
2 files changed, 11 insertions(+)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 464947f76d..15cf6021a0 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2311,6 +2311,16 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev,
int n, uint16_t idx)
vdev->vq[n].shadow_avail_idx = idx;
}
+void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
+{
+ rcu_read_lock();
+ if (vdev->vq[n].vring.desc) {
+ vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
+ vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx;
+ }
+ rcu_read_unlock();
+}
+
void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
{
rcu_read_lock();
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 80c45c321e..3d5c84e829 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -272,6 +272,7 @@ hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int
n);
hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n);
uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n);
void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx);
+void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n);
void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n);
void virtio_queue_update_used_idx(VirtIODevice *vdev, int n);
VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n);
--
2.11.0
