Re: [PATCH v9 18/29] iommufd/selftest: Add coverage for the new mmap interface

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@nvidia.com

Reviewed-by: Pranjal Shrivastava praan@google.com

---

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