From cb30dfa75d55eced379a42fd67bd5fb7ec38555e Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 8 Oct 2025 15:17:18 -0300 Subject: [PATCH 1/3] iommufd: Don't overflow during division for dirty tracking If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow to 0 and this triggers divide by 0. In this case the index should just be 0, so reorganize things to divide by shift and avoid hitting any overflows. Link: https://patch.msgid.link/r/0-v1-663679b57226+172-iommufd_dirty_div0_jgg@nvidia.com Cc: stable@vger.kernel.org Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support") Reviewed-by: Joao Martins Reviewed-by: Nicolin Chen Reviewed-by: Kevin Tian Reported-by: syzbot+093a8a8b859472e6c257@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=093a8a8b859472e6c257 Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/iova_bitmap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c index 4514575818fc..b5b67a9d3fb3 100644 --- a/drivers/iommu/iommufd/iova_bitmap.c +++ b/drivers/iommu/iommufd/iova_bitmap.c @@ -130,9 +130,8 @@ struct iova_bitmap { static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap, unsigned long iova) { - unsigned long pgsize = 1UL << bitmap->mapped.pgshift; - - return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize); + return (iova >> bitmap->mapped.pgshift) / + BITS_PER_TYPE(*bitmap->bitmap); } /* From b09ed52db1e688eb8205b1939ca1345179ecd515 Mon Sep 17 00:00:00 2001 From: Nicolin Chen Date: Tue, 14 Oct 2025 14:48:46 -0700 Subject: [PATCH 2/3] iommufd/selftest: Fix ioctl return value in _test_cmd_trigger_vevents() The ioctl returns 0 upon success, so !0 returning -1 breaks the selftest. Drop the '!' to fix it. Fixes: 1d235d849425 ("iommu/selftest: prevent use of uninitialized variable") Link: https://patch.msgid.link/r/20251014214847.1113759-1-nicolinc@nvidia.com Signed-off-by: Nicolin Chen Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe --- tools/testing/selftests/iommu/iommufd_utils.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h index 772ca1db6e59..9f472c20c190 100644 --- a/tools/testing/selftests/iommu/iommufd_utils.h +++ b/tools/testing/selftests/iommu/iommufd_utils.h @@ -1044,8 +1044,8 @@ static int _test_cmd_trigger_vevents(int fd, __u32 dev_id, __u32 nvevents) }; while (nvevents--) { - if (!ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT), - &trigger_vevent_cmd)) + if (ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT), + &trigger_vevent_cmd)) return -1; } return 0; From afb47765f9235181fddc61c8633b5a8cfae29fd2 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Tue, 4 Nov 2025 14:11:49 -0400 Subject: [PATCH 3/3] 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: d624d6652a65 ("iommufd: vfio container FD ioctl compatibility") Link: https://patch.msgid.link/r/0-v1-76be45eff0be+5d-iommufd_unmap_compat_jgg@nvidia.com Reviewed-by: Nicolin Chen Reviewed-by: Alex Mastro Reported-by: Alex Mastro Closes: https://lore.kernel.org/r/aP0S5ZF9l3sWkJ1G@devgpu012.nha5.facebook.com Signed-off-by: Jason Gunthorpe --- 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 c0360c450880..75d60f2ad900 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 1542c5fd10a8..459a7c516915 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 3eebf5e3b974..bb4d33dde3c8 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));