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

Fixes: d624d6652a65 ("iommufd: vfio container FD ioctl compatibility") Reported-by: Alex Mastro amastro@fb.com Closes: https://lore.kernel.org/r/aP0S5ZF9l3sWkJ1G@devgpu012.nha5.facebook.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- drivers/iommu/iommufd/io_pagetable.c | 12 +++--------- drivers/iommu/iommufd/ioas.c | 4 ++++ tools/testing/selftests/iommu/iommufd.c | 2 ++ 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/iommufd/io_pagetable.c b/drivers/iommu/iommufd/io_pagetable.c index c0360c450880b8..75d60f2ad90082 100644 --- a/drivers/iommu/iommufd/io_pagetable.c +++ b/drivers/iommu/iommufd/io_pagetable.c @@ -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. */ diff --git a/drivers/iommu/iommufd/ioas.c b/drivers/iommu/iommufd/ioas.c index 1542c5fd10a85c..459a7c5169154b 100644 --- a/drivers/iommu/iommufd/ioas.c +++ b/drivers/iommu/iommufd/ioas.c @@ -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; diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index 3eebf5e3b974f4..bb4d33dde3c899 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -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));

base-commit: b09ed52db1e688eb8205b1939ca1345179ecd515