Add comprehensive selftest for VFIO device operations with iommufd in
noiommu mode. Tests cover:
- Device binding to iommufd
- IOAS (I/O Address Space) allocation, mapping with dummy IOVA
- Retrieve PA from dummy IOVA
- Device attach/detach operations as usual

Signed-off-by: Jacob Pan <jacob.pan@linux.microsoft.com>
---
v2:
   - Use huge page ioas map to test GET_PA searching for contiguous PA
     range.
---
 tools/testing/selftests/vfio/Makefile         |   1 +
 .../vfio/vfio_iommufd_noiommu_test.c          | 549 ++++++++++++++++++
 2 files changed, 550 insertions(+)
 create mode 100644 tools/testing/selftests/vfio/vfio_iommufd_noiommu_test.c

diff --git a/tools/testing/selftests/vfio/Makefile b/tools/testing/selftests/vfio/Makefile
index 8e90e409e91d..90f41d8ce3c7 100644
--- a/tools/testing/selftests/vfio/Makefile
+++ b/tools/testing/selftests/vfio/Makefile
@@ -9,6 +9,7 @@ CFLAGS = $(KHDR_INCLUDES)
 TEST_GEN_PROGS += vfio_dma_mapping_test
 TEST_GEN_PROGS += vfio_dma_mapping_mmio_test
 TEST_GEN_PROGS += vfio_iommufd_setup_test
+TEST_GEN_PROGS += vfio_iommufd_noiommu_test
 TEST_GEN_PROGS += vfio_pci_device_test
 TEST_GEN_PROGS += vfio_pci_device_init_perf_test
 TEST_GEN_PROGS += vfio_pci_driver_test
diff --git a/tools/testing/selftests/vfio/vfio_iommufd_noiommu_test.c b/tools/testing/selftests/vfio/vfio_iommufd_noiommu_test.c
new file mode 100644
index 000000000000..c4e4fcd09342
--- /dev/null
+++ b/tools/testing/selftests/vfio/vfio_iommufd_noiommu_test.c
@@ -0,0 +1,549 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VFIO iommufd NoIOMMU Mode Selftest
+ *
+ * Tests VFIO device operations with iommufd in noiommu mode, including:
+ * - Device binding to iommufd
+ * - IOAS (I/O Address Space) allocation and management
+ * - Device attach/detach to IOAS
+ * - Memory mapping in IOAS
+ * - Device info queries and reset
+ */
+
+#include <linux/limits.h>
+#include <linux/vfio.h>
+#include <linux/iommufd.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <libvfio.h>
+#include "kselftest_harness.h"
+
+static const char iommu_dev_path[] = "/dev/iommu";
+static const char *cdev_path;
+
+static char *vfio_noiommu_get_device_id(const char *bdf)
+{
+	char *path = NULL;
+	char *vfio_id = NULL;
+	struct dirent *dentry;
+	DIR *dp;
+
+	if (asprintf(&path, "/sys/bus/pci/devices/%s/vfio-dev", bdf) < 0)
+		return NULL;
+
+	dp = opendir(path);
+	if (!dp) {
+		free(path);
+		return NULL;
+	}
+
+	while ((dentry = readdir(dp)) != NULL) {
+		if (strncmp("noiommu-vfio", dentry->d_name, 12) == 0) {
+			vfio_id = strdup(dentry->d_name);
+			break;
+		}
+	}
+
+	closedir(dp);
+	free(path);
+	return vfio_id;
+}
+
+static char *vfio_noiommu_get_cdev_path(const char *bdf)
+{
+	char *vfio_id = vfio_noiommu_get_device_id(bdf);
+	char *cdev = NULL;
+
+	if (vfio_id) {
+		asprintf(&cdev, "/dev/vfio/devices/%s", vfio_id);
+		free(vfio_id);
+	}
+	return cdev;
+}
+
+static int vfio_device_bind_iommufd_ioctl(int cdev_fd, int iommufd)
+{
+	struct vfio_device_bind_iommufd bind_args = {
+		.argsz = sizeof(bind_args),
+		.iommufd = iommufd,
+	};
+
+	return ioctl(cdev_fd, VFIO_DEVICE_BIND_IOMMUFD, &bind_args);
+}
+
+static int vfio_device_get_info_ioctl(int cdev_fd,
+				      struct vfio_device_info *info)
+{
+	info->argsz = sizeof(*info);
+	return ioctl(cdev_fd, VFIO_DEVICE_GET_INFO, info);
+}
+
+static int vfio_device_ioas_alloc_ioctl(int iommufd,
+					struct iommu_ioas_alloc *alloc_args)
+{
+	alloc_args->size = sizeof(*alloc_args);
+	alloc_args->flags = 0;
+	return ioctl(iommufd, IOMMU_IOAS_ALLOC, alloc_args);
+}
+
+static int vfio_device_attach_iommufd_pt_ioctl(int cdev_fd, u32 pt_id)
+{
+	struct vfio_device_attach_iommufd_pt attach_args = {
+		.argsz = sizeof(attach_args),
+		.pt_id = pt_id,
+	};
+
+	return ioctl(cdev_fd, VFIO_DEVICE_ATTACH_IOMMUFD_PT, &attach_args);
+}
+
+static int vfio_device_detach_iommufd_pt_ioctl(int cdev_fd)
+{
+	struct vfio_device_detach_iommufd_pt detach_args = {
+		.argsz = sizeof(detach_args),
+	};
+
+	return ioctl(cdev_fd, VFIO_DEVICE_DETACH_IOMMUFD_PT, &detach_args);
+}
+
+static int vfio_device_get_region_info_ioctl(int cdev_fd, uint32_t index,
+					     struct vfio_region_info *info)
+{
+	info->argsz = sizeof(*info);
+	info->index = index;
+	return ioctl(cdev_fd, VFIO_DEVICE_GET_REGION_INFO, info);
+}
+
+static int vfio_device_reset_ioctl(int cdev_fd)
+{
+	return ioctl(cdev_fd, VFIO_DEVICE_RESET);
+}
+
+static int ioas_map_pages(int iommufd, uint32_t ioas_id, uint64_t iova,
+			  size_t length, bool hugepages)
+{
+	struct iommu_ioas_map map_args = {
+		.size = sizeof(map_args),
+		.ioas_id = ioas_id,
+		.iova = iova,
+		.length = length,
+		.flags = IOMMU_IOAS_MAP_READABLE | IOMMU_IOAS_MAP_WRITEABLE | IOMMU_IOAS_MAP_FIXED_IOVA,
+	};
+	void *pages;
+	int ret;
+
+	/* Allocate test pages */
+	if (hugepages)
+		pages = mmap(NULL, length, PROT_READ | PROT_WRITE,
+			     MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
+	else
+		pages = mmap(NULL, length, PROT_READ | PROT_WRITE,
+			     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (pages == MAP_FAILED) {
+		printf("mmap failed for length 0x%lx\n", (unsigned long)length);
+		return -ENOMEM;
+	}
+
+	/* Set up page pointer for mapping */
+	map_args.user_va = (uintptr_t)pages;
+
+	printf("  ioas_map_pages: ioas_id=%u, iova=0x%lx, length=0x%lx, user_va=%p\n",
+	       ioas_id, (unsigned long)iova, (unsigned long)length, pages);
+
+	/* Map into IOAS */
+	ret = ioctl(iommufd, IOMMU_IOAS_MAP, &map_args);
+	if (ret != 0)
+		printf("  IOMMU_IOAS_MAP failed: %d (%s)\n", ret, strerror(errno));
+	else
+		printf("  IOMMU_IOAS_MAP succeeded, IOVA=0x%lx\n", (unsigned long)map_args.iova);
+
+	munmap(pages, length);
+	return ret;
+}
+
+static int ioas_unmap_pages(int iommufd, uint32_t ioas_id, uint64_t iova,
+			    size_t length)
+{
+	struct iommu_ioas_unmap unmap_args = {
+		.size = sizeof(unmap_args),
+		.ioas_id = ioas_id,
+		.iova = iova,
+		.length = length,
+	};
+
+	return ioctl(iommufd, IOMMU_IOAS_UNMAP, &unmap_args);
+}
+
+static int ioas_destroy_ioctl(int iommufd, uint32_t ioas_id)
+{
+	struct iommu_destroy destroy_args = {
+		.size = sizeof(destroy_args),
+		.id = ioas_id,
+	};
+
+	return ioctl(iommufd, IOMMU_DESTROY, &destroy_args);
+}
+
+static int ioas_get_pa_ioctl(int iommufd, uint32_t ioas_id, uint64_t iova,
+			     uint64_t *phys_out, uint64_t *length_out)
+{
+	struct {
+		__u32 size;
+		__u32 flags;
+		__u32 ioas_id;
+		__u32 __reserved;
+		__u64 iova;
+		__u64 out_length;
+		__u64 out_phys;
+	} get_pa = {
+		.size = sizeof(get_pa),
+		.flags = 0,
+		.ioas_id = ioas_id,
+		.iova = iova,
+	};
+
+	printf("  ioas_get_pa_ioctl: ioas_id=%u, iova=0x%lx\n",
+	       ioas_id, (unsigned long)iova);
+
+	if (ioctl(iommufd, IOMMU_IOAS_GET_PA, &get_pa) != 0) {
+		printf("  IOMMU_IOAS_GET_PA failed: %s (errno=%d)\n",
+		       strerror(errno), errno);
+		return -1;
+	}
+
+	printf("  IOMMU_IOAS_GET_PA succeeded: PA=0x%lx, length=0x%lx\n",
+	       (unsigned long)get_pa.out_phys, (unsigned long)get_pa.out_length);
+
+	if (phys_out)
+		*phys_out = get_pa.out_phys;
+	if (length_out)
+		*length_out = get_pa.out_length;
+
+	return 0;
+}
+
+FIXTURE(vfio_noiommu) {
+	int cdev_fd;
+	int iommufd;
+};
+
+FIXTURE_SETUP(vfio_noiommu)
+{
+	ASSERT_LE(0, (self->cdev_fd = open(cdev_path, O_RDWR, 0)));
+	ASSERT_LE(0, (self->iommufd = open(iommu_dev_path, O_RDWR, 0)));
+}
+
+FIXTURE_TEARDOWN(vfio_noiommu)
+{
+	if (self->cdev_fd >= 0)
+		close(self->cdev_fd);
+	if (self->iommufd >= 0)
+		close(self->iommufd);
+}
+
+/*
+ * Test: Device cdev can be opened
+ */
+TEST_F(vfio_noiommu, device_cdev_open)
+{
+	ASSERT_LE(0, self->cdev_fd);
+}
+
+/*
+ * Test: Device can be bound to iommufd
+ */
+TEST_F(vfio_noiommu, device_bind_iommufd)
+{
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+}
+
+/*
+ * Test: Device info can be queried after binding
+ */
+TEST_F(vfio_noiommu, device_get_info_after_bind)
+{
+	struct vfio_device_info info;
+
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_EQ(0, vfio_device_get_info_ioctl(self->cdev_fd, &info));
+	ASSERT_NE(0, info.argsz);
+}
+
+/*
+ * Test: Getting device info fails without bind
+ */
+TEST_F(vfio_noiommu, device_get_info_without_bind_fails)
+{
+	struct vfio_device_info info;
+
+	ASSERT_NE(0, vfio_device_get_info_ioctl(self->cdev_fd, &info));
+}
+
+/*
+ * Test: Binding with invalid iommufd fails
+ */
+TEST_F(vfio_noiommu, device_bind_bad_iommufd_fails)
+{
+	ASSERT_NE(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd, -2));
+}
+
+/*
+ * Test: Cannot bind twice to same device
+ */
+TEST_F(vfio_noiommu, device_repeated_bind_fails)
+{
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_NE(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+}
+
+/*
+ * Test: IOAS can be allocated
+ */
+TEST_F(vfio_noiommu, ioas_alloc)
+{
+	struct iommu_ioas_alloc alloc_args;
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+	ASSERT_NE(0, alloc_args.out_ioas_id);
+}
+
+/*
+ * Test: IOAS can be destroyed
+ */
+TEST_F(vfio_noiommu, ioas_destroy)
+{
+	struct iommu_ioas_alloc alloc_args;
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+	ASSERT_EQ(0, ioas_destroy_ioctl(self->iommufd,
+					alloc_args.out_ioas_id));
+}
+
+/*
+ * Test: Device can attach to IOAS after binding
+ */
+TEST_F(vfio_noiommu, device_attach_to_ioas)
+{
+	struct iommu_ioas_alloc alloc_args;
+
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+	ASSERT_EQ(0, vfio_device_attach_iommufd_pt_ioctl(self->cdev_fd,
+							 alloc_args.out_ioas_id));
+}
+
+/*
+ * Test: Attaching to invalid IOAS fails
+ */
+TEST_F(vfio_noiommu, device_attach_invalid_ioas_fails)
+{
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_NE(0, vfio_device_attach_iommufd_pt_ioctl(self->cdev_fd,
+							 UINT32_MAX));
+}
+
+/*
+ * Test: Device can detach from IOAS
+ */
+TEST_F(vfio_noiommu, device_detach_from_ioas)
+{
+	struct iommu_ioas_alloc alloc_args;
+
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+	ASSERT_EQ(0, vfio_device_attach_iommufd_pt_ioctl(self->cdev_fd,
+							 alloc_args.out_ioas_id));
+	ASSERT_EQ(0, vfio_device_detach_iommufd_pt_ioctl(self->cdev_fd));
+}
+
+/*
+ * Test: Full lifecycle - bind, attach, detach, reset
+ */
+TEST_F(vfio_noiommu, device_lifecycle)
+{
+	struct iommu_ioas_alloc alloc_args;
+	struct vfio_device_info info;
+
+	/* Bind device to iommufd */
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+
+	/* Allocate IOAS */
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+
+	/* Attach device to IOAS */
+	ASSERT_EQ(0, vfio_device_attach_iommufd_pt_ioctl(self->cdev_fd,
+							 alloc_args.out_ioas_id));
+
+	/* Query device info */
+	ASSERT_EQ(0, vfio_device_get_info_ioctl(self->cdev_fd, &info));
+
+	/* Detach device from IOAS */
+	ASSERT_EQ(0, vfio_device_detach_iommufd_pt_ioctl(self->cdev_fd));
+
+	/* Reset device */
+	ASSERT_EQ(0, vfio_device_reset_ioctl(self->cdev_fd));
+}
+
+/*
+ * Test: Get region info
+ */
+TEST_F(vfio_noiommu, device_get_region_info)
+{
+	struct vfio_device_info dev_info;
+	struct vfio_region_info region_info;
+
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_EQ(0, vfio_device_get_info_ioctl(self->cdev_fd, &dev_info));
+
+	/* Try to get first region info if device has regions */
+	if (dev_info.num_regions > 0) {
+		ASSERT_EQ(0, vfio_device_get_region_info_ioctl(self->cdev_fd, 0,
+							       &region_info));
+		ASSERT_NE(0, region_info.argsz);
+	}
+}
+
+TEST_F(vfio_noiommu, device_reset)
+{
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+	ASSERT_EQ(0, vfio_device_reset_ioctl(self->cdev_fd));
+}
+
+TEST_F(vfio_noiommu, ioas_map_pages)
+{
+	struct iommu_ioas_alloc alloc_args;
+	long page_size = sysconf(_SC_PAGESIZE);
+	uint64_t iova = 0x10000;
+	int i;
+
+	ASSERT_GT(page_size, 0);
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+
+	printf("Page size: %ld bytes\n", page_size);
+	/* Test mapping regions of different sizes: 1, 2, 4, 8 pages */
+	for (i = 0; i < 4; i++) {
+		size_t map_size = page_size * (1 << i);  /* 1, 2, 4, 8 pages */
+		uint64_t test_iova = iova + (i * 0x100000);
+
+		/* Attempt to map each region (may fail if not supported) */
+		ioas_map_pages(self->iommufd, alloc_args.out_ioas_id,
+			       test_iova, map_size, false);
+	}
+}
+
+TEST_F(vfio_noiommu, multiple_ioas_alloc)
+{
+	struct iommu_ioas_alloc alloc1, alloc2;
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd, &alloc1));
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd, &alloc2));
+	ASSERT_NE(alloc1.out_ioas_id, alloc2.out_ioas_id);
+}
+
+/*
+ * Test: Query physical address for IOVA
+ * Tests IOMMU_IOAS_GET_PA ioctl to translate IOVA to physical address
+ * Note: Device must be attached to IOAS for PA query to work
+ */
+#define NR_PAGES 32
+TEST_F(vfio_noiommu, ioas_get_pa_mapped)
+{
+	struct iommu_ioas_alloc alloc_args;
+	long page_size = sysconf(_SC_PAGESIZE);
+	uint64_t iova = 0x200000;
+	uint64_t phys = 0;
+	uint64_t length = 0;
+	int ret;
+
+	ASSERT_GT(page_size, 0);
+
+	ASSERT_EQ(0, vfio_device_bind_iommufd_ioctl(self->cdev_fd,
+						    self->iommufd));
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+
+	ASSERT_EQ(0, vfio_device_attach_iommufd_pt_ioctl(self->cdev_fd,
+							 alloc_args.out_ioas_id));
+
+	/*
+	 * Map a page into an arbitrary IOAS, used as a cookie for lookup.
+	 * Use hugepages to test contiguous PA. Make sure hugepages are
+	 * available. e.g.  echo 64 > /proc/sys/vm/nr_hugepages
+	 */
+	ret = ioas_map_pages(self->iommufd, alloc_args.out_ioas_id,
+			     iova, page_size * NR_PAGES, true);
+	if (ret != 0)
+		return;
+
+	/* Query the physical address for the mapped dummy IOVA */
+	ret = ioas_get_pa_ioctl(self->iommufd, alloc_args.out_ioas_id,
+			       iova, &phys, &length);
+
+	if (ret == 0) {
+		/* If we got a result, verify it's valid */
+		ASSERT_NE(0, phys);
+		ASSERT_GE((uint64_t)page_size * NR_PAGES, length);
+	}
+}
+
+TEST_F(vfio_noiommu, ioas_get_pa_unmapped_fails)
+{
+	struct iommu_ioas_alloc alloc_args;
+
+	ASSERT_EQ(0, vfio_device_ioas_alloc_ioctl(self->iommufd,
+						  &alloc_args));
+
+	/* Try to retrieve unmapped IOVA (should fail) */
+	ASSERT_NE(0, ioas_get_pa_ioctl(self->iommufd, alloc_args.out_ioas_id,
+				       0x10000, NULL, NULL));
+}
+
+int main(int argc, char *argv[])
+{
+	const char *device_bdf = vfio_selftests_get_bdf(&argc, argv);
+	char *cdev = NULL;
+
+	if (!device_bdf) {
+		ksft_print_msg("No device BDF provided\n");
+		return KSFT_SKIP;
+	}
+
+	cdev = vfio_noiommu_get_cdev_path(device_bdf);
+	if (!cdev) {
+		ksft_print_msg("Could not find cdev for device %s\n",
+			       device_bdf);
+		return KSFT_SKIP;
+	}
+
+	cdev_path = cdev;
+	ksft_print_msg("Using cdev device %s for BDF %s\n", cdev_path,
+		       device_bdf);
+
+	return test_harness_run(argc, argv);
+}
-- 
2.34.1