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author | 2023-03-02 19:18:57 +0100 | |
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committer | 2023-03-13 02:29:12 -0400 | |
commit | b4cca6d48eb3fa6f0d9caba4329b1a2b0ff67a77 (patch) | |
tree | f1210b41149ec5866b469ade97c8dcd19449e507 /drivers | |
parent | vhost-vdpa: free iommu domain after last use during cleanup (diff) | |
download | linux-b4cca6d48eb3fa6f0d9caba4329b1a2b0ff67a77.tar.gz linux-b4cca6d48eb3fa6f0d9caba4329b1a2b0ff67a77.tar.bz2 linux-b4cca6d48eb3fa6f0d9caba4329b1a2b0ff67a77.zip |
vdpa_sim: set last_used_idx as last_avail_idx in vdpasim_queue_ready
Starting from an used_idx different than 0 is needed in use cases like
virtual machine migration. Not doing so and letting the caller set an
avail idx different than 0 causes destination device to try to use old
buffers that source driver already recover and are not available
anymore.
Since vdpa_sim does not support receive inflight descriptors as a
destination of a migration, let's set both avail_idx and used_idx the
same at vq start. This is how vhost-user works in a
VHOST_SET_VRING_BASE call.
Although the simple fix is to set last_used_idx at vdpasim_set_vq_state,
it would be reset at vdpasim_queue_ready. The last_avail_idx case is
fixed with commit 0e84f918fac8 ("vdpa_sim: not reset state in
vdpasim_queue_ready"). Since the only option is to make it equal to
last_avail_idx, adding the only change needed here.
This was discovered and tested live migrating the vdpa_sim_net device.
Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230302181857.925374-1-eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/vdpa/vdpa_sim/vdpa_sim.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c index 6a0a65814626..eea23c630f7c 100644 --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c @@ -68,6 +68,17 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx) (uintptr_t)vq->device_addr); vq->vring.last_avail_idx = last_avail_idx; + + /* + * Since vdpa_sim does not support receive inflight descriptors as a + * destination of a migration, let's set both avail_idx and used_idx + * the same at vq start. This is how vhost-user works in a + * VHOST_SET_VRING_BASE call. + * + * Although the simple fix is to set last_used_idx at + * vdpasim_set_vq_state, it would be reset at vdpasim_queue_ready. + */ + vq->vring.last_used_idx = last_avail_idx; vq->vring.notify = vdpasim_vq_notify; } |