vdpa/mlx5: Fix suspend/resume index restoration
When we suspend the VM, the VDPA interface will be reset. When the VM is
resumed again, clear_virtqueues() will clear the available and used
indices resulting in hardware virqtqueue objects becoming out of sync.
We can avoid this function alltogether since qemu will clear them if
required, e.g. when the VM went through a reboot.
Moreover, since the hw available and used indices should always be
identical on query and should be restored to the same value same value
for virtqueues that complete in order, we set the single value provided
by set_vq_state(). In get_vq_state() we return the value of hardware
used index.
Fixes: b35ccebe3ef7 ("vdpa/mlx5: Restore the hardware used index after change map")
Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20210408091047.4269-6-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 6fe61fc..4d2809c 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1169,6 +1169,7 @@
return;
}
mvq->avail_idx = attr.available_index;
+ mvq->used_idx = attr.used_index;
}
static void suspend_vqs(struct mlx5_vdpa_net *ndev)
@@ -1426,6 +1427,7 @@
return -EINVAL;
}
+ mvq->used_idx = state->avail_index;
mvq->avail_idx = state->avail_index;
return 0;
}
@@ -1443,7 +1445,11 @@
* that cares about emulating the index after vq is stopped.
*/
if (!mvq->initialized) {
- state->avail_index = mvq->avail_idx;
+ /* Firmware returns a wrong value for the available index.
+ * Since both values should be identical, we take the value of
+ * used_idx which is reported correctly.
+ */
+ state->avail_index = mvq->used_idx;
return 0;
}
@@ -1452,7 +1458,7 @@
mlx5_vdpa_warn(mvdev, "failed to query virtqueue\n");
return err;
}
- state->avail_index = attr.available_index;
+ state->avail_index = attr.used_index;
return 0;
}
@@ -1540,16 +1546,6 @@
}
}
-static void clear_virtqueues(struct mlx5_vdpa_net *ndev)
-{
- int i;
-
- for (i = ndev->mvdev.max_vqs - 1; i >= 0; i--) {
- ndev->vqs[i].avail_idx = 0;
- ndev->vqs[i].used_idx = 0;
- }
-}
-
/* TODO: cross-endian support */
static inline bool mlx5_vdpa_is_little_endian(struct mlx5_vdpa_dev *mvdev)
{
@@ -1785,7 +1781,6 @@
if (!status) {
mlx5_vdpa_info(mvdev, "performing device reset\n");
teardown_driver(ndev);
- clear_virtqueues(ndev);
mlx5_vdpa_destroy_mr(&ndev->mvdev);
ndev->mvdev.status = 0;
ndev->mvdev.mlx_features = 0;
