[PATCH v8 18/29] iommufd/selftest: Add coverage for the new mmap interface

Nicolin Chen
2025-07-05T01:14:45Z

Extend the loopback test to a new mmap page.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.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 6b88c250b505..8b85f6fc8cd0 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