linux-stable/drivers/vdpa
Eugenio Pérez ee6ef81377 vdpa_sim: set last_used_idx as last_avail_idx in vdpasim_queue_ready
[ Upstream commit b4cca6d48e ]

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 0e84f918fa ("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: 2c53d0f64c ("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>
2023-03-22 13:31:24 +01:00
..
ifcvf vdpa/ifcvf: fix the calculation of queuepair 2022-10-05 10:39:43 +02:00
mlx5 vdpa/mlx5: Initialize CVQ vringh only once 2022-07-21 21:24:33 +02:00
vdpa_sim vdpa_sim: set last_used_idx as last_avail_idx in vdpasim_queue_ready 2023-03-22 13:31:24 +01:00
vdpa_user vduse: Validate vq_num in vduse_validate_config() 2023-01-24 07:22:41 +01:00
virtio_pci
Kconfig
Makefile
vdpa.c vdpa: Fix error logic in vdpa_nl_cmd_dev_get_doit 2022-06-14 18:36:12 +02:00