On Wed, Jul 09, 2025 at 10:59:10PM -0700, Nicolin Chen wrote:
> Extend the loopback test to a new mmap page.
>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Reviewed-by: Pranjal Shrivastava <praan@xxxxxxxxxx>
> ---
> drivers/iommu/iommufd/iommufd_test.h | 4 +++
> tools/testing/selftests/iommu/iommufd_utils.h | 4 +++
> drivers/iommu/iommufd/selftest.c | 33 ++++++++++++++++++-
> tools/testing/selftests/iommu/iommufd.c | 19 +++++++++++
> 4 files changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/iommufd/iommufd_test.h b/drivers/iommu/iommufd/iommufd_test.h
> index 51cd744a354f..8fc618b2bcf9 100644
> --- a/drivers/iommu/iommufd/iommufd_test.h
> +++ b/drivers/iommu/iommufd/iommufd_test.h
> @@ -232,12 +232,16 @@ struct iommu_hwpt_invalidate_selftest {
> * (IOMMU_VIOMMU_TYPE_SELFTEST)
> * @in_data: Input random data from user space
> * @out_data: Output data (matching @in_data) to user space
> + * @out_mmap_offset: The offset argument for mmap syscall
> + * @out_mmap_length: The length argument for mmap syscall
> *
> * Simply set @out_data=@in_data for a loopback test
> */
> struct iommu_viommu_selftest {
> __u32 in_data;
> __u32 out_data;
> + __aligned_u64 out_mmap_offset;
> + __aligned_u64 out_mmap_length;
> };
>
> /* Should not be equal to any defined value in enum iommu_viommu_invalidate_data_type */
> diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h
> index 9a556f99d992..4a1b2bade018 100644
> --- a/tools/testing/selftests/iommu/iommufd_utils.h
> +++ b/tools/testing/selftests/iommu/iommufd_utils.h
> @@ -56,6 +56,10 @@ static unsigned long PAGE_SIZE;
> #define offsetofend(TYPE, MEMBER) \
> (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
>
> +#define test_err_mmap(_errno, length, offset) \
> + EXPECT_ERRNO(_errno, (long)mmap(NULL, length, PROT_READ | PROT_WRITE, \
> + MAP_SHARED, self->fd, offset))
> +
> static inline void *memfd_mmap(size_t length, int prot, int flags, int *mfd_p)
> {
> int mfd_flags = (flags & MAP_HUGETLB) ? MFD_HUGETLB : 0;
> diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
> index 2189e9b119ee..8b2c44b32530 100644
> --- a/drivers/iommu/iommufd/selftest.c
> +++ b/drivers/iommu/iommufd/selftest.c
> @@ -152,6 +152,9 @@ struct mock_viommu {
> struct mock_iommu_domain *s2_parent;
> struct mock_hw_queue *hw_queue[IOMMU_TEST_HW_QUEUE_MAX];
> struct mutex queue_mutex;
> +
> + unsigned long mmap_offset;
> + u32 *page; /* Mmap page to test u32 type of in_data */
> };
>
> static inline struct mock_viommu *to_mock_viommu(struct iommufd_viommu *viommu)
> @@ -689,6 +692,10 @@ static void mock_viommu_destroy(struct iommufd_viommu *viommu)
>
> if (refcount_dec_and_test(&mock_iommu->users))
> complete(&mock_iommu->complete);
> + if (mock_viommu->mmap_offset)
> + iommufd_viommu_destroy_mmap(&mock_viommu->core,
> + mock_viommu->mmap_offset);
> + free_page((unsigned long)mock_viommu->page);
> mutex_destroy(&mock_viommu->queue_mutex);
>
> /* iommufd core frees mock_viommu and viommu */
> @@ -887,11 +894,28 @@ static int mock_viommu_init(struct iommufd_viommu *viommu,
> if (rc)
> return rc;
>
> + /* Allocate two pages */
> + mock_viommu->page =
> + (u32 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
> + if (!mock_viommu->page)
> + return -ENOMEM;
> +
> + rc = iommufd_viommu_alloc_mmap(&mock_viommu->core,
> + __pa(mock_viommu->page),
> + PAGE_SIZE * 2,
> + &mock_viommu->mmap_offset);
> + if (rc)
> + goto err_free_page;
> +
> + /* For loopback tests on both the page and out_data */
> + *mock_viommu->page = data.in_data;
> data.out_data = data.in_data;
> + data.out_mmap_length = PAGE_SIZE * 2;
> + data.out_mmap_offset = mock_viommu->mmap_offset;
> rc = iommu_copy_struct_to_user(
> user_data, &data, IOMMU_VIOMMU_TYPE_SELFTEST, out_data);
> if (rc)
> - return rc;
> + goto err_destroy_mmap;
> }
>
> refcount_inc(&mock_iommu->users);
> @@ -900,6 +924,13 @@ static int mock_viommu_init(struct iommufd_viommu *viommu,
>
> viommu->ops = &mock_viommu_ops;
> return 0;
> +
> +err_destroy_mmap:
> + iommufd_viommu_destroy_mmap(&mock_viommu->core,
> + mock_viommu->mmap_offset);
> +err_free_page:
> + free_page((unsigned long)mock_viommu->page);
> + return rc;
> }
>
> static const struct iommu_ops mock_ops = {
> diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
> index 73426de77675..0b21c095ca5e 100644
> --- a/tools/testing/selftests/iommu/iommufd.c
> +++ b/tools/testing/selftests/iommu/iommufd.c
> @@ -2799,6 +2799,7 @@ TEST_F(iommufd_viommu, viommu_alloc_with_data)
> struct iommu_viommu_selftest data = {
> .in_data = 0xbeef,
> };
> + uint32_t *test;
>
> if (!self->device_id)
> SKIP(return, "Skipping test for variant no_viommu");
> @@ -2807,6 +2808,24 @@ TEST_F(iommufd_viommu, viommu_alloc_with_data)
> IOMMU_VIOMMU_TYPE_SELFTEST, &data, sizeof(data),
> &self->viommu_id);
> ASSERT_EQ(data.out_data, data.in_data);
> +
> + /* Negative mmap tests -- offset and length cannot be changed */
> + test_err_mmap(ENXIO, data.out_mmap_length,
> + data.out_mmap_offset + PAGE_SIZE);
> + test_err_mmap(ENXIO, data.out_mmap_length,
> + data.out_mmap_offset + PAGE_SIZE * 2);
> + test_err_mmap(ENXIO, data.out_mmap_length / 2, data.out_mmap_offset);
> + test_err_mmap(ENXIO, data.out_mmap_length * 2, data.out_mmap_offset);
> +
> + /* Now do a correct mmap for a loopback test */
> + test = mmap(NULL, data.out_mmap_length, PROT_READ | PROT_WRITE,
> + MAP_SHARED, self->fd, data.out_mmap_offset);
> + ASSERT_NE(MAP_FAILED, test);
> + ASSERT_EQ(data.in_data, *test);
> +
> + /* The owner of the mmap region should be blocked */
> + EXPECT_ERRNO(EBUSY, _test_ioctl_destroy(self->fd, self->viommu_id));
> + munmap(test, data.out_mmap_length);
> }
>
> TEST_F(iommufd_viommu, vdevice_alloc)
> --
> 2.43.0
>
