From: Eli Cohen elic@nvidia.com
[ Upstream commit 08dbd5660232bede7916d8568003012c1182cc9a ]
The current code treats an empty iotlb provdied in set_map() as a special case and destroy the memory region object. This must not be done since the virtqueue objects reference this MR. Doing so will cause the driver unload to emit errors and log timeouts caused by the firmware complaining on busy resources.
This patch treats an empty iotlb as any other change of mapping. In this case, mlx5_vdpa_create_mr() will fail and the entire set_map() call to fail.
This issue has not been encountered before but was seen to occur in a non-official version of qemu. Since qemu is a userspace program, the driver must protect against such case.
Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code") Signed-off-by: Eli Cohen elic@nvidia.com Link: https://lore.kernel.org/r/20210811053713.66658-1-elic@nvidia.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vdpa/mlx5/core/mr.c | 9 --------- 1 file changed, 9 deletions(-)
diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c index aa656f57bf5b..32c9925de473 100644 --- a/drivers/vdpa/mlx5/core/mr.c +++ b/drivers/vdpa/mlx5/core/mr.c @@ -454,11 +454,6 @@ out: mutex_unlock(&mr->mkey_mtx); }
-static bool map_empty(struct vhost_iotlb *iotlb) -{ - return !vhost_iotlb_itree_first(iotlb, 0, U64_MAX); -} - int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *iotlb, bool *change_map) { @@ -466,10 +461,6 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io int err = 0;
*change_map = false; - if (map_empty(iotlb)) { - mlx5_vdpa_destroy_mr(mvdev); - return 0; - } mutex_lock(&mr->mkey_mtx); if (mr->initialized) { mlx5_vdpa_info(mvdev, "memory map update\n");