[PATCH 2/4] vfio: selftests: Add memfd test to vfio_dma_mapping_perf_test

[Aaron Lewis <aaronlewis@google.com>]

Add a second test to "vfio_dma_mapping_perf_test" to evaluate memfd
latencies. A key motivator for adding this test is to demonstrate that
the IOMMU_IOAS_MAP_FILE ioctl is significantly faster than other methods
of mapping DMA regions. While this performance difference is not fully
apparent with the test's current capabilities, it will become evident
as more features are introduced later in the series.

To support this, add IOMMU_IOAS_MAP_FILE ioctl support to the VFIO
selftest library via iommufd_map_file().

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 .../vfio/lib/include/libvfio/iommu.h          |   7 ++
 tools/testing/selftests/vfio/lib/iommu.c      |  24 ++++
 .../vfio/vfio_dma_mapping_perf_test.c         | 118 ++++++++++++++++++
 3 files changed, 149 insertions(+)

diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
index e9a3386a4719..eeef5990292c 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
@@ -35,6 +35,13 @@ struct iommu {
 struct iommu *iommu_init(const char *iommu_mode);
 void iommu_cleanup(struct iommu *iommu);
 
+int __iommufd_map_file(struct iommu *iommu, struct dma_region *region, int fd);
+
+static inline void iommufd_map_file(struct iommu *iommu, struct dma_region *region, int fd)
+{
+	VFIO_ASSERT_EQ(__iommufd_map_file(iommu, region, fd), 0);
+}
+
 int __iommu_map(struct iommu *iommu, struct dma_region *region);
 
 static inline void iommu_map(struct iommu *iommu, struct dma_region *region)
diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c
index 035dac069d60..6730b39060ca 100644
--- a/tools/testing/selftests/vfio/lib/iommu.c
+++ b/tools/testing/selftests/vfio/lib/iommu.c
@@ -97,6 +97,30 @@ iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr)
 	return iova;
 }
 
+int __iommufd_map_file(struct iommu *iommu, struct dma_region *region, int fd)
+{
+	VFIO_ASSERT_TRUE(iommu->iommufd, "IOMMU_IOAS_MAP_FILE is an IOMMUFD IOCTL.");
+
+	struct iommu_ioas_map_file args = {
+		.size = sizeof(args),
+		.flags = IOMMU_IOAS_MAP_READABLE |
+			IOMMU_IOAS_MAP_WRITEABLE |
+			IOMMU_IOAS_MAP_FIXED_IOVA,
+		.ioas_id = iommu->ioas_id,
+		.fd = fd,
+		.start = 0,
+		.iova = region->iova,
+		.length = region->size,
+	};
+
+	if (ioctl(iommu->iommufd, IOMMU_IOAS_MAP_FILE, &args))
+		return -errno;
+
+	list_add(&region->link, &iommu->dma_regions);
+
+	return 0;
+}
+
 static int vfio_iommu_map(struct iommu *iommu, struct dma_region *region)
 {
 	struct vfio_iommu_type1_dma_map args = {
diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c
index 87d84450fc47..4639bda7ebaa 100644
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c
@@ -117,6 +117,124 @@ TEST_F(vfio_dma_mapping_perf_test, dma_map_unmap)
 	printf("Completed munmap() in %.2lfms\n", timer_elapsed_ms(start));
 }
 
+FIXTURE(vfio_dma_mapping_perf_memfd_test) {
+	struct iommu *iommu;
+	struct vfio_pci_device *device;
+	struct iova_allocator *iova_allocator;
+};
+
+FIXTURE_VARIANT(vfio_dma_mapping_perf_memfd_test) {
+	const char *iommu_mode;
+	int mmap_flags;
+	int memfd_flags;
+};
+
+#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _mmap_flags, _memfd_flags) \
+FIXTURE_VARIANT_ADD(vfio_dma_mapping_perf_memfd_test, _iommu_mode ## _ ## _name) {    \
+	.iommu_mode = #_iommu_mode,						      \
+	.mmap_flags = MAP_SHARED | (_mmap_flags),				      \
+	.memfd_flags = MAP_SHARED | (_memfd_flags),				      \
+}
+
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(memfd, 0, 0);
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(memfd_hugetlb_2mb,
+				    MAP_HUGETLB | MAP_HUGE_2MB,
+				    MFD_HUGETLB | MFD_HUGE_2MB);
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(memfd_hugetlb_1gb,
+				    MAP_HUGETLB | MAP_HUGE_1GB,
+				    MFD_HUGETLB | MFD_HUGE_1GB);
+
+#undef FIXTURE_VARIANT_ADD_IOMMU_MODE
+
+FIXTURE_SETUP(vfio_dma_mapping_perf_memfd_test)
+{
+	self->iommu = iommu_init(variant->iommu_mode);
+	self->device = vfio_pci_device_init(device_bdf, self->iommu);
+	self->iova_allocator = iova_allocator_init(self->iommu);
+}
+
+FIXTURE_TEARDOWN(vfio_dma_mapping_perf_memfd_test)
+{
+	iova_allocator_cleanup(self->iova_allocator);
+	vfio_pci_device_cleanup(self->device);
+	iommu_cleanup(self->iommu);
+}
+
+static void *setup_memfd(int *fd, u64 size, int mmap_flags, int mfd_flags)
+{
+	void *buf = MAP_FAILED;
+	struct timespec start;
+
+	timer_start(&start);
+	*fd = memfd_create("vfio_dma_mapping_perf_memfd_test", mfd_flags);
+	printf("Completed memfd_create() in %.2lfms\n", timer_elapsed_ms(start));
+	if (*fd <= 0)
+		return MAP_FAILED;
+
+	if (ftruncate(*fd, size))
+		goto out;
+
+	timer_start(&start);
+	buf = mmap(NULL, size, PROT_READ | PROT_WRITE, mmap_flags, *fd, 0);
+	printf("Completed mmap() for memfd in %.2lfms\n", timer_elapsed_ms(start));
+
+out:
+	if (buf == MAP_FAILED)
+		close(*fd);
+
+	return buf;
+}
+
+static void teardown_memfd(int fd, u64 size, void *vaddr)
+{
+	struct timespec start;
+
+	if (vaddr != MAP_FAILED) {
+		timer_start(&start);
+		munmap(vaddr, size);
+		printf("Completed munmap() in %.2lfms\n", timer_elapsed_ms(start));
+	}
+
+	if (fd != -1) {
+		timer_start(&start);
+		close(fd);
+		printf("Completed close() in %.2lfms\n", timer_elapsed_ms(start));
+	}
+}
+
+TEST_F(vfio_dma_mapping_perf_memfd_test, dma_map_unmap_from_file)
+{
+	const u64 size = SZ_1G;
+	struct dma_region region;
+	struct timespec start;
+	u64 unmapped;
+	int rc, fd;
+
+	region.vaddr = setup_memfd(&fd, size, variant->mmap_flags, variant->memfd_flags);
+	ASSERT_NE(region.vaddr, MAP_FAILED);
+
+	region.iova = iova_allocator_alloc(self->iova_allocator, size);
+	region.size = size;
+
+	timer_start(&start);
+	if (strcmp(variant->iommu_mode, MODE_IOMMUFD) == 0) {
+		iommufd_map_file(self->iommu, &region, fd);
+	} else {
+		iommu_map(self->iommu, &region);
+	}
+	printf("Mapped HVA %p (size %luG) at IOVA 0x%lx in %.2lfms\n",
+	       region.vaddr, size / SZ_1G, region.iova, timer_elapsed_ms(start));
+	ASSERT_EQ(region.iova, to_iova(self->device, region.vaddr));
+
+	timer_start(&start);
+	rc = __iommu_unmap(self->iommu, &region, &unmapped);
+	printf("Unmapped IOVA 0x%lx in %.2lfms\n", region.iova, timer_elapsed_ms(start));
+	ASSERT_EQ(rc, 0);
+	ASSERT_EQ(unmapped, region.size);
+
+	teardown_memfd(fd, size, region.vaddr);
+}
+
 int main(int argc, char *argv[])
 {
 	device_bdf = vfio_selftests_get_bdf(&argc, argv);
-- 
2.55.0.rc0.799.gd6f94ed593-goog