vfio: selftests: Support multiple devices in the same container/iommufd

Support tests that want to add multiple devices to the same
container/iommufd by decoupling struct vfio_pci_device from
struct iommu.

Multi-devices tests can now put multiple devices in the same
container/iommufd like so:

  iommu = iommu_init(iommu_mode);

  device1 = vfio_pci_device_init(bdf1, iommu);
  device2 = vfio_pci_device_init(bdf2, iommu);
  device3 = vfio_pci_device_init(bdf3, iommu);

  ...

  vfio_pci_device_cleanup(device3);
  vfio_pci_device_cleanup(device2);
  vfio_pci_device_cleanup(device1);

  iommu_cleanup(iommu);

To account for the new separation of vfio_pci_device and iommu, update
existing tests to initialize and cleanup a struct iommu.

Reviewed-by: Alex Mastro <amastro@fb.com>
Tested-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20251126231733.3302983-7-dmatlack@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

2 files changed, 70 insertions, 41 deletions

diff --git a/tools/testing/selftests/vfio/lib/include/vfio_util.h b/tools/testing/selftests/vfio/lib/include/vfio_util.h
index 3160f2d1ea6d..379942dc5357 100644
--- a/tools/testing/selftests/vfio/lib/include/vfio_util.h
+++ b/tools/testing/selftests/vfio/lib/include/vfio_util.h
@@ -216,8 +216,12 @@ const char *vfio_pci_get_cdev_path(const char *bdf);
 
 extern const char *default_iommu_mode;
 
-struct vfio_pci_device *vfio_pci_device_init(const char *bdf, const char *iommu_mode);
+struct iommu *iommu_init(const char *iommu_mode);
+void iommu_cleanup(struct iommu *iommu);
+
+struct vfio_pci_device *vfio_pci_device_init(const char *bdf, struct iommu *iommu);
 void vfio_pci_device_cleanup(struct vfio_pci_device *device);
+
 void vfio_pci_device_reset(struct vfio_pci_device *device);
 
 struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device,
diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
index e47f3ccf6d49..8f8fed4f384d 100644
--- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
@@ -86,13 +86,13 @@ static struct vfio_iommu_type1_info *vfio_iommu_get_info(struct vfio_pci_device
 		.argsz = sizeof(*info),
 	};
 
-	ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, info);
+	ioctl_assert(device->iommu->container_fd, VFIO_IOMMU_GET_INFO, info);
 	VFIO_ASSERT_GE(info->argsz, sizeof(*info));
 
 	info = realloc(info, info->argsz);
 	VFIO_ASSERT_NOT_NULL(info);
 
-	ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, info);
+	ioctl_assert(device->iommu->container_fd, VFIO_IOMMU_GET_INFO, info);
 	VFIO_ASSERT_GE(info->argsz, sizeof(*info));
 
 	return info;
@@ -142,10 +142,10 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct vfio_pci_device *devi
 
 	struct iommu_ioas_iova_ranges query = {
 		.size = sizeof(query),
-		.ioas_id = device->ioas_id,
+		.ioas_id = device->iommu->ioas_id,
 	};
 
-	ret = ioctl(device->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
+	ret = ioctl(device->iommu->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
 	VFIO_ASSERT_EQ(ret, -1);
 	VFIO_ASSERT_EQ(errno, EMSGSIZE);
 	VFIO_ASSERT_GT(query.num_iovas, 0);
@@ -155,7 +155,7 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct vfio_pci_device *devi
 
 	query.allowed_iovas = (uintptr_t)ranges;
 
-	ioctl_assert(device->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
+	ioctl_assert(device->iommu->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
 	*nranges = query.num_iovas;
 
 	return ranges;
@@ -180,7 +180,7 @@ struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device,
 {
 	struct iommu_iova_range *ranges;
 
-	if (device->iommufd)
+	if (device->iommu->iommufd)
 		ranges = iommufd_iova_ranges(device, nranges);
 	else
 		ranges = vfio_iommu_iova_ranges(device, nranges);
@@ -633,23 +633,21 @@ static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf
 
 static void vfio_pci_container_setup(struct vfio_pci_device *device, const char *bdf)
 {
-	unsigned long iommu_type = device->iommu->mode->iommu_type;
-	const char *path = device->iommu->mode->container_path;
-	int version;
+	struct iommu *iommu = device->iommu;
+	unsigned long iommu_type = iommu->mode->iommu_type;
 	int ret;
 
-	device->iommu->container_fd = open(path, O_RDWR);
-	VFIO_ASSERT_GE(device->iommu->container_fd, 0, "open(%s) failed\n", path);
-
-	version = ioctl(device->iommu->container_fd, VFIO_GET_API_VERSION);
-	VFIO_ASSERT_EQ(version, VFIO_API_VERSION, "Unsupported version: %d\n", version);
-
 	vfio_pci_group_setup(device, bdf);
 
-	ret = ioctl(device->iommu->container_fd, VFIO_CHECK_EXTENSION, iommu_type);
+	ret = ioctl(iommu->container_fd, VFIO_CHECK_EXTENSION, iommu_type);
 	VFIO_ASSERT_GT(ret, 0, "VFIO IOMMU type %lu not supported\n", iommu_type);
 
-	ioctl_assert(device->iommu->container_fd, VFIO_SET_IOMMU, (void *)iommu_type);
+	/*
+	 * Allow multiple threads to race to set the IOMMU type on the
+	 * container. The first will succeed and the rest should fail
+	 * because the IOMMU type is already set.
+	 */
+	(void)ioctl(iommu->container_fd, VFIO_SET_IOMMU, (void *)iommu_type);
 
 	device->fd = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, bdf);
 	VFIO_ASSERT_GE(device->fd, 0);
@@ -797,34 +795,56 @@ static void vfio_pci_iommufd_setup(struct vfio_pci_device *device, const char *b
 	VFIO_ASSERT_GE(device->fd, 0);
 	free((void *)cdev_path);
 
-	/*
-	 * Require device->iommufd to be >0 so that a simple non-0 check can be
-	 * used to check if iommufd is enabled. In practice open() will never
-	 * return 0 unless stdin is closed.
-	 */
-	device->iommu->iommufd = open("/dev/iommu", O_RDWR);
-	VFIO_ASSERT_GT(device->iommu->iommufd, 0);
-
 	vfio_device_bind_iommufd(device->fd, device->iommu->iommufd);
-	device->iommu->ioas_id = iommufd_ioas_alloc(device->iommu->iommufd);
 	vfio_device_attach_iommufd_pt(device->fd, device->iommu->ioas_id);
 }
 
-struct vfio_pci_device *vfio_pci_device_init(const char *bdf, const char *iommu_mode)
+struct iommu *iommu_init(const char *iommu_mode)
+{
+	const char *container_path;
+	struct iommu *iommu;
+	int version;
+
+	iommu = calloc(1, sizeof(*iommu));
+	VFIO_ASSERT_NOT_NULL(iommu);
+
+	INIT_LIST_HEAD(&iommu->dma_regions);
+
+	iommu->mode = lookup_iommu_mode(iommu_mode);
+
+	container_path = iommu->mode->container_path;
+	if (container_path) {
+		iommu->container_fd = open(container_path, O_RDWR);
+		VFIO_ASSERT_GE(iommu->container_fd, 0, "open(%s) failed\n", container_path);
+
+		version = ioctl(iommu->container_fd, VFIO_GET_API_VERSION);
+		VFIO_ASSERT_EQ(version, VFIO_API_VERSION, "Unsupported version: %d\n", version);
+	} else {
+		/*
+		 * Require device->iommufd to be >0 so that a simple non-0 check can be
+		 * used to check if iommufd is enabled. In practice open() will never
+		 * return 0 unless stdin is closed.
+		 */
+		iommu->iommufd = open("/dev/iommu", O_RDWR);
+		VFIO_ASSERT_GT(iommu->iommufd, 0);
+
+		iommu->ioas_id = iommufd_ioas_alloc(iommu->iommufd);
+	}
+
+	return iommu;
+}
+
+struct vfio_pci_device *vfio_pci_device_init(const char *bdf, struct iommu *iommu)
 {
 	struct vfio_pci_device *device;
 
 	device = calloc(1, sizeof(*device));
 	VFIO_ASSERT_NOT_NULL(device);
 
-	device->iommu = calloc(1, sizeof(*device->iommu));
-	VFIO_ASSERT_NOT_NULL(device->iommu);
-
-	INIT_LIST_HEAD(&device->iommu->dma_regions);
-
-	device->iommu->mode = lookup_iommu_mode(iommu_mode);
+	VFIO_ASSERT_NOT_NULL(iommu);
+	device->iommu = iommu;
 
-	if (device->iommu->mode->container_path)
+	if (iommu->mode->container_path)
 		vfio_pci_container_setup(device, bdf);
 	else
 		vfio_pci_iommufd_setup(device, bdf);
@@ -853,17 +873,22 @@ void vfio_pci_device_cleanup(struct vfio_pci_device *device)
 		VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
 	}
 
-	if (device->iommu->iommufd) {
-		VFIO_ASSERT_EQ(close(device->iommu->iommufd), 0);
-	} else {
+	if (device->group_fd)
 		VFIO_ASSERT_EQ(close(device->group_fd), 0);
-		VFIO_ASSERT_EQ(close(device->iommu->container_fd), 0);
-	}
 
-	free(device->iommu);
 	free(device);
 }
 
+void iommu_cleanup(struct iommu *iommu)
+{
+	if (iommu->iommufd)
+		VFIO_ASSERT_EQ(close(iommu->iommufd), 0);
+	else
+		VFIO_ASSERT_EQ(close(iommu->container_fd), 0);
+
+	free(iommu);
+}
+
 static bool is_bdf(const char *str)
 {
 	unsigned int s, b, d, f;