[PATCH vhost v2] vdpa/mlx5: Fix oversized null mkey longer than 32bit

[Dragos Tatulea <dtatulea@nvidia.com>]

From: Si-Wei Liu <si-wei.liu@oracle.com>

create_user_mr() has correct code to count the number of null keys
used to fill in a hole for the memory map. However, fill_indir()
does not follow the same to cap the range up to the 1GB limit
correspondingly. Fill in more null keys for the gaps in between,
so that null keys are correctly populated.

Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
Cc: stable@vger.kernel.org
Reported-by: Cong Meng <cong.meng@oracle.com>
Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
---
Changes in v2:
- Added Reported-by tag.
- Fixed typo found during review.
---
 drivers/vdpa/mlx5/core/mr.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
index 8455f08f5d40..61424342c096 100644
--- a/drivers/vdpa/mlx5/core/mr.c
+++ b/drivers/vdpa/mlx5/core/mr.c
@@ -190,9 +190,12 @@ static void fill_indir(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mkey, v
 			klm->bcount = cpu_to_be32(klm_bcount(dmr->end - dmr->start));
 			preve = dmr->end;
 		} else {
+			u64 bcount = min_t(u64, dmr->start - preve, MAX_KLM_SIZE);
+
 			klm->key = cpu_to_be32(mvdev->res.null_mkey);
-			klm->bcount = cpu_to_be32(klm_bcount(dmr->start - preve));
-			preve = dmr->start;
+			klm->bcount = cpu_to_be32(klm_bcount(bcount));
+			preve += bcount;
+
 			goto again;
 		}
 	}
-- 
2.43.0