From 08dbd5660232bede7916d8568003012c1182cc9a Mon Sep 17 00:00:00 2001 From: Eli Cohen Date: Wed, 11 Aug 2021 08:37:13 +0300 Subject: [PATCH] vdpa/mlx5: Avoid destroying MR on empty iotlb 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 Link: https://lore.kernel.org/r/20210811053713.66658-1-elic@nvidia.com Signed-off-by: Michael S. Tsirkin --- 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 dcee603..e59135f 100644 --- a/drivers/vdpa/mlx5/core/mr.c +++ b/drivers/vdpa/mlx5/core/mr.c @@ -512,11 +512,6 @@ 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) { @@ -524,10 +519,6 @@ 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"); -- 2.7.4