linux-kernel - [PATCH v2 14/22] iommufd/selftest: Add coverage for the new mmap interface

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Message-ID: <4682c7707606f54ad4ef62d3f1218a4870819c03.1745646960.git.nicolinc@nvidia.com>
Date: Fri, 25 Apr 2025 22:58:09 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: <jgg@...dia.com>, <kevin.tian@...el.com>, <corbet@....net>,
	<will@...nel.org>
CC: <bagasdotme@...il.com>, <robin.murphy@....com>, <joro@...tes.org>,
	<thierry.reding@...il.com>, <vdumpa@...dia.com>, <jonathanh@...dia.com>,
	<shuah@...nel.org>, <jsnitsel@...hat.com>, <nathan@...nel.org>,
	<peterz@...radead.org>, <yi.l.liu@...el.com>, <mshavit@...gle.com>,
	<praan@...gle.com>, <zhangzekun11@...wei.com>, <iommu@...ts.linux.dev>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-tegra@...r.kernel.org>,
	<linux-kselftest@...r.kernel.org>, <patches@...ts.linux.dev>,
	<mochs@...dia.com>, <alok.a.tiwari@...cle.com>, <vasant.hegde@....com>
Subject: [PATCH v2 14/22] iommufd/selftest: Add coverage for the new mmap interface

Extend the loopback test to a new mmap page.

Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
 drivers/iommu/iommufd/iommufd_test.h    |  4 +++
 drivers/iommu/iommufd/selftest.c        | 37 ++++++++++++++++++++++---
 tools/testing/selftests/iommu/iommufd.c |  5 ++++
 3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_test.h b/drivers/iommu/iommufd/iommufd_test.h
index a0831d78fef1..86a983f59552 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_pgoff: The offset argument for mmap syscall
+ * @out_mmap_pgsz: Maximum page size for mmap syscall
  *
  * Simply set @out_data=@...data for a loopback test
  */
 struct iommu_viommu_selftest {
 	__u32 in_data;
 	__u32 out_data;
+	__aligned_u64 out_mmap_pgoff;
+	__aligned_u64 out_mmap_pgsz;
 };
 
 /* Should not be equal to any defined value in enum iommu_viommu_invalidate_data_type */
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index d6cc5b78821b..cd058dcd5984 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -149,6 +149,9 @@ struct mock_viommu {
 	struct iommufd_viommu core;
 	struct mock_iommu_domain *s2_parent;
 	struct mock_vcmdq *mock_vcmdq[IOMMU_TEST_VCMDQ_MAX];
+
+	unsigned long mmap_pgoff;
+	u32 *page; /* Mmap page to test u32 type of in_data */
 };
 
 static inline struct mock_viommu *to_mock_viommu(struct iommufd_viommu *viommu)
@@ -645,9 +648,12 @@ static void mock_viommu_destroy(struct iommufd_viommu *viommu)
 {
 	struct mock_iommu_device *mock_iommu = container_of(
 		viommu->iommu_dev, struct mock_iommu_device, iommu_dev);
+	struct mock_viommu *mock_viommu = to_mock_viommu(viommu);
 
 	if (refcount_dec_and_test(&mock_iommu->users))
 		complete(&mock_iommu->complete);
+	iommufd_ctx_free_mmap(viommu->ictx, mock_viommu->mmap_pgoff);
+	free_page((unsigned long)mock_viommu->page);
 
 	/* iommufd core frees mock_viommu and viommu */
 }
@@ -827,17 +833,40 @@ mock_viommu_alloc(struct device *dev, struct iommu_domain *domain,
 		return ERR_CAST(mock_viommu);
 
 	if (user_data) {
+		mock_viommu->page =
+			(u32 *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+		if (!mock_viommu->page) {
+			rc = -ENOMEM;
+			goto err_destroy_struct;
+		}
+
+		rc = iommufd_ctx_alloc_mmap(ictx, __pa(mock_viommu->page),
+					    PAGE_SIZE,
+					    &mock_viommu->mmap_pgoff);
+		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_pgsz = PAGE_SIZE;
+		data.out_mmap_pgoff = mock_viommu->mmap_pgoff;
 		rc = iommu_copy_struct_to_user(
 			user_data, &data, IOMMU_VIOMMU_TYPE_SELFTEST, out_data);
-		if (rc) {
-			iommufd_struct_destroy(ictx, mock_viommu, core);
-			return ERR_PTR(rc);
-		}
+		if (rc)
+			goto err_free_mmap;
 	}
 
 	refcount_inc(&mock_iommu->users);
 	return &mock_viommu->core;
+
+err_free_mmap:
+	iommufd_ctx_free_mmap(ictx, mock_viommu->mmap_pgoff);
+err_free_page:
+	free_page((unsigned long)mock_viommu->page);
+err_destroy_struct:
+	iommufd_struct_destroy(ictx, mock_viommu, core);
+	return ERR_PTR(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 7c464f6eb37b..f6dbee6a352c 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -2799,12 +2799,17 @@ TEST_F(iommufd_viommu, viommu_alloc_with_data)
 	struct iommu_viommu_selftest data = {
 		.in_data = 0xbeef,
 	};
+	uint32_t *test;
 
 	if (self->device_id) {
 		test_cmd_viommu_alloc(self->device_id, self->hwpt_id,
 				      IOMMU_VIOMMU_TYPE_SELFTEST, &data,
 				      sizeof(data), &self->viommu_id);
 		assert(data.out_data == data.in_data);
+		test = mmap(NULL, data.out_mmap_pgsz, PROT_READ | PROT_WRITE,
+			    MAP_SHARED, self->fd, data.out_mmap_pgoff);
+		assert(test && *test == data.in_data);
+		munmap(test, data.out_mmap_pgsz);
 	}
 }
 
-- 
2.43.0