From a3da1ab6fbea7d5cbcb796f62c8771d8ebd7282a Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 19 May 2022 14:03:48 -0300 Subject: vfio: Do not manipulate iommu dma_owner for fake iommu groups Since asserting dma ownership now causes the group to have its DMA blocked the iommu layer requires a working iommu. This means the dma_owner APIs cannot be used on the fake groups that VFIO creates. Test for this and avoid calling them. Otherwise asserting dma ownership will fail for VFIO mdev devices as a BLOCKING iommu_domain cannot be allocated due to the NULL iommu ops. Fixes: 0286300e6045 ("iommu: iommu_group_claim_dma_owner() must always assign a domain") Reported-by: Eric Farman Tested-by: Eric Farman Signed-off-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/0-v1-9cfc47edbcd4+13546-vfio_dma_owner_fix_jgg@nvidia.com Signed-off-by: Alex Williamson --- drivers/vfio/vfio.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'drivers/vfio') diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index cfcff7764403..f5ed03897210 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -927,7 +927,8 @@ static void __vfio_group_unset_container(struct vfio_group *group) driver->ops->detach_group(container->iommu_data, group->iommu_group); - iommu_group_release_dma_owner(group->iommu_group); + if (group->type == VFIO_IOMMU) + iommu_group_release_dma_owner(group->iommu_group); group->container = NULL; group->container_users = 0; @@ -1001,9 +1002,11 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd) goto unlock_out; } - ret = iommu_group_claim_dma_owner(group->iommu_group, f.file); - if (ret) - goto unlock_out; + if (group->type == VFIO_IOMMU) { + ret = iommu_group_claim_dma_owner(group->iommu_group, f.file); + if (ret) + goto unlock_out; + } driver = container->iommu_driver; if (driver) { @@ -1011,7 +1014,9 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd) group->iommu_group, group->type); if (ret) { - iommu_group_release_dma_owner(group->iommu_group); + if (group->type == VFIO_IOMMU) + iommu_group_release_dma_owner( + group->iommu_group); goto unlock_out; } } -- cgit v1.2.3