diff options
| author | Eugenio Pérez | 2023-03-02 19:18:57 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-03-22 13:33:44 +0100 |
| commit | 1e803737141f71e4bd9d3e0b63b715d6ed09e49a (patch) | |
| tree | bd02d8ae07ad67a0cb2ee56fc3936e63a5f08efe | |
| parent | 6efd13e9acd1422025f5a5b4b7328bf475404546 (diff) | |
vdpa_sim: set last_used_idx as last_avail_idx in vdpasim_queue_ready
[ Upstream commit b4cca6d48eb3fa6f0d9caba4329b1a2b0ff67a77 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 8839232a3fcb..61bde476cf9c 100644 --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c @@ -76,6 +76,17 @@ 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; } |