Commit afb47765 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

iommufd: Make vfio_compat's unmap succeed if the range is already empty 

iommufd returns ENOENT when attempting to unmap a range that is already
empty, while vfio type1 returns success. Fix vfio_compat to match.

Fixes: d624d665 ("iommufd: vfio container FD ioctl compatibility")
Link: https://patch.msgid.link/r/0-v1-76be45eff0be+5d-iommufd_unmap_compat_jgg@nvidia.com


Reviewed-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Reviewed-by: default avatarAlex Mastro <amastro@fb.com>
Reported-by: default avatarAlex Mastro <amastro@fb.com>
Closes: https://lore.kernel.org/r/aP0S5ZF9l3sWkJ1G@devgpu012.nha5.facebook.com


Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent b09ed52d

drivers/iommu/iommufd/io_pagetable.c

+3 −9
Original line number Diff line number Diff line
@@ -707,7 +707,8 @@ static int iopt_unmap_iova_range(struct io_pagetable *iopt, unsigned long start, 
	struct iopt_area *area;

	unsigned long unmapped_bytes = 0;

	unsigned int tries = 0;

	int rc = -ENOENT;

	/* If there are no mapped entries then success */

	int rc = 0;



	/*

	 * The domains_rwsem must be held in read mode any time any area->pages
@@ -777,8 +778,6 @@ static int iopt_unmap_iova_range(struct io_pagetable *iopt, unsigned long start, 


		down_write(&iopt->iova_rwsem);

	}

	if (unmapped_bytes)

		rc = 0;



out_unlock_iova:

	up_write(&iopt->iova_rwsem);
@@ -815,13 +814,8 @@ int iopt_unmap_iova(struct io_pagetable *iopt, unsigned long iova, 


int iopt_unmap_all(struct io_pagetable *iopt, unsigned long *unmapped)

{

	int rc;



	rc = iopt_unmap_iova_range(iopt, 0, ULONG_MAX, unmapped);

	/* If the IOVAs are empty then unmap all succeeds */

	if (rc == -ENOENT)

		return 0;

	return rc;

	return iopt_unmap_iova_range(iopt, 0, ULONG_MAX, unmapped);

}



/* The caller must always free all the nodes in the allowed_iova rb_root. */

drivers/iommu/iommufd/ioas.c

+4 −0
Original line number Diff line number Diff line
@@ -367,6 +367,10 @@ int iommufd_ioas_unmap(struct iommufd_ucmd *ucmd) 
				     &unmapped);

		if (rc)

			goto out_put;

		if (!unmapped) {

			rc = -ENOENT;

			goto out_put;

		}

	}



	cmd->length = unmapped;

tools/testing/selftests/iommu/iommufd.c

+2 −0
Original line number Diff line number Diff line
@@ -2638,6 +2638,8 @@ TEST_F(vfio_compat_mock_domain, map) 
	ASSERT_EQ(0, ioctl(self->fd, VFIO_IOMMU_MAP_DMA, &map_cmd));

	ASSERT_EQ(0, ioctl(self->fd, VFIO_IOMMU_UNMAP_DMA, &unmap_cmd));

	ASSERT_EQ(BUFFER_SIZE, unmap_cmd.size);

	/* Unmap of empty is success */

	ASSERT_EQ(0, ioctl(self->fd, VFIO_IOMMU_UNMAP_DMA, &unmap_cmd));



	/* UNMAP_FLAG_ALL requires 0 iova/size */

	ASSERT_EQ(0, ioctl(self->fd, VFIO_IOMMU_MAP_DMA, &map_cmd));