vfio: selftests: Add iommufd mode

Add a new IOMMU mode for using iommufd directly. In this mode userspace
opens /dev/iommu and binds it to a device FD acquired through
/dev/vfio/devices/vfioX.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-29-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/tools/testing/selftests/vfio/lib/include/vfio_util.h b/tools/testing/selftests/vfio/lib/include/vfio_util.h
index 035ef5b9d678058cdad5b1b3eff95adc61deb1be..ed31606e01b78584583f5d6631974255362edd6e 100644 (file)
--- a/tools/testing/selftests/vfio/lib/include/vfio_util.h
+++ b/tools/testing/selftests/vfio/lib/include/vfio_util.h
@@ -62,7 +62,8 @@ struct vfio_iommu_mode {
 FIXTURE_VARIANT_ADD_IOMMU_MODE(vfio_type1_iommu, ##__VA_ARGS__); \
 FIXTURE_VARIANT_ADD_IOMMU_MODE(vfio_type1v2_iommu, ##__VA_ARGS__); \
 FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd_compat_type1, ##__VA_ARGS__); \
-FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd_compat_type1v2, ##__VA_ARGS__)
+FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd_compat_type1v2, ##__VA_ARGS__); \
+FIXTURE_VARIANT_ADD_IOMMU_MODE(iommufd, ##__VA_ARGS__)
 
 struct vfio_pci_bar {
        struct vfio_region_info info;
@@ -166,6 +167,9 @@ struct vfio_pci_device {
        int group_fd;
        int container_fd;
 
+       int iommufd;
+       u32 ioas_id;
+
        struct vfio_device_info info;
        struct vfio_region_info config_space;
        struct vfio_pci_bar bars[PCI_STD_NUM_BARS];

diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
index b6fefe2b3ec8e42b8aea3482d193463f2a1dbf90..5d8944a37982c1ddddd3675b7fe00103a2db3ad1 100644 (file)
--- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
@@ -10,10 +10,12 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 
+#include <uapi/linux/types.h>
 #include <linux/limits.h>
 #include <linux/mman.h>
 #include <linux/types.h>
 #include <linux/vfio.h>
+#include <linux/iommufd.h>
 
 #include "../../../kselftest.h"
 #include <vfio_util.h>
@@ -139,32 +141,80 @@ static void vfio_pci_irq_get(struct vfio_pci_device *device, u32 index,
        ioctl_assert(device->fd, VFIO_DEVICE_GET_IRQ_INFO, irq_info);
 }
 
-void vfio_pci_dma_map(struct vfio_pci_device *device,
-                     struct vfio_dma_region *region)
+static void vfio_iommu_dma_map(struct vfio_pci_device *device,
+                              struct vfio_dma_region *region)
 {
-       struct vfio_iommu_type1_dma_map map = {
-               .argsz = sizeof(map),
+       struct vfio_iommu_type1_dma_map args = {
+               .argsz = sizeof(args),
                .flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
                .vaddr = (u64)region->vaddr,
                .iova = region->iova,
                .size = region->size,
        };
 
-       ioctl_assert(device->container_fd, VFIO_IOMMU_MAP_DMA, &map);
+       ioctl_assert(device->container_fd, VFIO_IOMMU_MAP_DMA, &args);
+}
+
+static void iommufd_dma_map(struct vfio_pci_device *device,
+                           struct vfio_dma_region *region)
+{
+       struct iommu_ioas_map args = {
+               .size = sizeof(args),
+               .flags = IOMMU_IOAS_MAP_READABLE |
+                        IOMMU_IOAS_MAP_WRITEABLE |
+                        IOMMU_IOAS_MAP_FIXED_IOVA,
+               .user_va = (u64)region->vaddr,
+               .iova = region->iova,
+               .length = region->size,
+               .ioas_id = device->ioas_id,
+       };
+
+       ioctl_assert(device->iommufd, IOMMU_IOAS_MAP, &args);
+}
+
+void vfio_pci_dma_map(struct vfio_pci_device *device,
+                     struct vfio_dma_region *region)
+{
+       if (device->iommufd)
+               iommufd_dma_map(device, region);
+       else
+               vfio_iommu_dma_map(device, region);
 
        list_add(&region->link, &device->dma_regions);
 }
 
-void vfio_pci_dma_unmap(struct vfio_pci_device *device,
-                       struct vfio_dma_region *region)
+static void vfio_iommu_dma_unmap(struct vfio_pci_device *device,
+                                struct vfio_dma_region *region)
 {
-       struct vfio_iommu_type1_dma_unmap unmap = {
-               .argsz = sizeof(unmap),
+       struct vfio_iommu_type1_dma_unmap args = {
+               .argsz = sizeof(args),
                .iova = region->iova,
                .size = region->size,
        };
 
-       ioctl_assert(device->container_fd, VFIO_IOMMU_UNMAP_DMA, &unmap);
+       ioctl_assert(device->container_fd, VFIO_IOMMU_UNMAP_DMA, &args);
+}
+
+static void iommufd_dma_unmap(struct vfio_pci_device *device,
+                             struct vfio_dma_region *region)
+{
+       struct iommu_ioas_unmap args = {
+               .size = sizeof(args),
+               .iova = region->iova,
+               .length = region->size,
+               .ioas_id = device->ioas_id,
+       };
+
+       ioctl_assert(device->iommufd, IOMMU_IOAS_UNMAP, &args);
+}
+
+void vfio_pci_dma_unmap(struct vfio_pci_device *device,
+                       struct vfio_dma_region *region)
+{
+       if (device->iommufd)
+               iommufd_dma_unmap(device, region);
+       else
+               vfio_iommu_dma_unmap(device, region);
 
        list_del(&region->link);
 }
@@ -258,18 +308,6 @@ static unsigned int vfio_pci_get_group_from_dev(const char *bdf)
        return group;
 }
 
-static void vfio_pci_container_setup(struct vfio_pci_device *device)
-{
-       const char *path = device->iommu_mode->container_path;
-       int version;
-
-       device->container_fd = open(path, O_RDWR);
-       VFIO_ASSERT_GE(device->container_fd, 0, "open(%s) failed\n", path);
-
-       version = ioctl(device->container_fd, VFIO_GET_API_VERSION);
-       VFIO_ASSERT_EQ(version, VFIO_API_VERSION);
-}
-
 static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf)
 {
        struct vfio_group_status group_status = {
@@ -290,26 +328,34 @@ static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf
        ioctl_assert(device->group_fd, VFIO_GROUP_SET_CONTAINER, &device->container_fd);
 }
 
-static void vfio_pci_iommu_setup(struct vfio_pci_device *device)
+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;
        int ret;
 
-       INIT_LIST_HEAD(&device->dma_regions);
+       device->container_fd = open(path, O_RDWR);
+       VFIO_ASSERT_GE(device->container_fd, 0, "open(%s) failed\n", path);
+
+       version = ioctl(device->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->container_fd, VFIO_CHECK_EXTENSION, iommu_type);
        VFIO_ASSERT_GT(ret, 0, "VFIO IOMMU type %lu not supported\n", iommu_type);
 
        ioctl_assert(device->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);
 }
 
-static void vfio_pci_device_setup(struct vfio_pci_device *device, const char *bdf)
+static void vfio_pci_device_setup(struct vfio_pci_device *device)
 {
        int i;
 
-       device->fd = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, bdf);
-       VFIO_ASSERT_GE(device->fd, 0);
-
        device->info.argsz = sizeof(device->info);
        ioctl_assert(device->fd, VFIO_DEVICE_GET_INFO, &device->info);
 
@@ -386,6 +432,9 @@ static const struct vfio_iommu_mode iommu_modes[] = {
                .container_path = "/dev/iommu",
                .iommu_type = VFIO_TYPE1v2_IOMMU,
        },
+       {
+               .name = "iommufd",
+       },
 };
 
 const char *default_iommu_mode = "vfio_type1_iommu";
@@ -407,6 +456,57 @@ static const struct vfio_iommu_mode *lookup_iommu_mode(const char *iommu_mode)
        VFIO_FAIL("Unrecognized IOMMU mode: %s\n", iommu_mode);
 }
 
+static void vfio_device_bind_iommufd(int device_fd, int iommufd)
+{
+       struct vfio_device_bind_iommufd args = {
+               .argsz = sizeof(args),
+               .iommufd = iommufd,
+       };
+
+       ioctl_assert(device_fd, VFIO_DEVICE_BIND_IOMMUFD, &args);
+}
+
+static u32 iommufd_ioas_alloc(int iommufd)
+{
+       struct iommu_ioas_alloc args = {
+               .size = sizeof(args),
+       };
+
+       ioctl_assert(iommufd, IOMMU_IOAS_ALLOC, &args);
+       return args.out_ioas_id;
+}
+
+static void vfio_device_attach_iommufd_pt(int device_fd, u32 pt_id)
+{
+       struct vfio_device_attach_iommufd_pt args = {
+               .argsz = sizeof(args),
+               .pt_id = pt_id,
+       };
+
+       ioctl_assert(device_fd, VFIO_DEVICE_ATTACH_IOMMUFD_PT, &args);
+}
+
+static void vfio_pci_iommufd_setup(struct vfio_pci_device *device, const char *bdf)
+{
+       const char *cdev_path = vfio_pci_get_cdev_path(bdf);
+
+       device->fd = open(cdev_path, O_RDWR);
+       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->iommufd = open("/dev/iommu", O_RDWR);
+       VFIO_ASSERT_GT(device->iommufd, 0);
+
+       vfio_device_bind_iommufd(device->fd, device->iommufd);
+       device->ioas_id = iommufd_ioas_alloc(device->iommufd);
+       vfio_device_attach_iommufd_pt(device->fd, device->ioas_id);
+}
+
 struct vfio_pci_device *vfio_pci_device_init(const char *bdf, const char *iommu_mode)
 {
        struct vfio_pci_device *device;
@@ -414,13 +514,16 @@ struct vfio_pci_device *vfio_pci_device_init(const char *bdf, const char *iommu_
        device = calloc(1, sizeof(*device));
        VFIO_ASSERT_NOT_NULL(device);
 
+       INIT_LIST_HEAD(&device->dma_regions);
+
        device->iommu_mode = lookup_iommu_mode(iommu_mode);
 
-       vfio_pci_container_setup(device);
-       vfio_pci_group_setup(device, bdf);
-       vfio_pci_iommu_setup(device);
-       vfio_pci_device_setup(device, bdf);
+       if (device->iommu_mode->container_path)
+               vfio_pci_container_setup(device, bdf);
+       else
+               vfio_pci_iommufd_setup(device, bdf);
 
+       vfio_pci_device_setup(device);
        vfio_pci_driver_probe(device);
 
        return device;
@@ -444,8 +547,12 @@ void vfio_pci_device_cleanup(struct vfio_pci_device *device)
                VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
        }
 
-       VFIO_ASSERT_EQ(close(device->group_fd), 0);
-       VFIO_ASSERT_EQ(close(device->container_fd), 0);
+       if (device->iommufd) {
+               VFIO_ASSERT_EQ(close(device->iommufd), 0);
+       } else {
+               VFIO_ASSERT_EQ(close(device->group_fd), 0);
+               VFIO_ASSERT_EQ(close(device->container_fd), 0);
+       }
 
        free(device);
 }