[RFC PATCH 1/3] vfio: selftests: Add support of creating iommus from iommufd
From: Samiullah Khawaja
Date: Thu Sep 24 2026 - 21:13:54 EST
Add API to init a struct iommu using an already opened iommufd instance
and attach devices to it.
Signed-off-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>
---
.../vfio/lib/include/libvfio/iommu.h | 2 +
.../lib/include/libvfio/vfio_pci_device.h | 2 +
tools/testing/selftests/vfio/lib/iommu.c | 60 +++++++++++++++++--
.../selftests/vfio/lib/vfio_pci_device.c | 25 ++++++--
4 files changed, 80 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
index e9a3386a4719..62f1e8affd2b 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
@@ -29,10 +29,12 @@ struct iommu {
int container_fd;
int iommufd;
u32 ioas_id;
+ u32 hwpt_id;
struct list_head dma_regions;
};
struct iommu *iommu_init(const char *iommu_mode);
+struct iommu *iommufd_iommu_init(int iommufd, u32 dev_id);
void iommu_cleanup(struct iommu *iommu);
int __iommu_map(struct iommu *iommu, struct dma_region *region);
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h
index e19bd94b8dd2..4dcc23bc9b78 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h
@@ -19,6 +19,7 @@ struct vfio_pci_device {
const char *bdf;
int fd;
int group_fd;
+ u32 dev_id;
struct iommu *iommu;
@@ -82,6 +83,7 @@ static inline void vfio_pci_cmd_clear(struct vfio_pci_device *device, u16 bits)
vfio_pci_config_writew(device, PCI_COMMAND, cmd & ~bits);
}
+void vfio_pci_device_attach_iommu(struct vfio_pci_device *device, struct iommu *iommu);
void vfio_pci_irq_enable(struct vfio_pci_device *device, u32 index,
u32 vector, int count);
void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index);
diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c
index b6f3c5c84e01..6d2d5c82813c 100644
--- a/tools/testing/selftests/vfio/lib/iommu.c
+++ b/tools/testing/selftests/vfio/lib/iommu.c
@@ -405,6 +405,18 @@ struct iommu_iova_range *iommu_iova_ranges(struct iommu *iommu, u32 *nranges)
return ranges;
}
+static u32 iommufd_hwpt_alloc(struct iommu *iommu, u32 dev_id)
+{
+ struct iommu_hwpt_alloc args = {
+ .size = sizeof(args),
+ .pt_id = iommu->ioas_id,
+ .dev_id = dev_id,
+ };
+
+ ioctl_assert(iommu->iommufd, IOMMU_HWPT_ALLOC, &args);
+ return args.out_hwpt_id;
+}
+
static u32 iommufd_ioas_alloc(int iommufd)
{
struct iommu_ioas_alloc args = {
@@ -415,17 +427,25 @@ static u32 iommufd_ioas_alloc(int iommufd)
return args.out_ioas_id;
}
-struct iommu *iommu_init(const char *iommu_mode)
+static struct iommu *iommu_alloc(const char *iommu_mode)
{
- const char *container_path;
struct iommu *iommu;
- int version;
iommu = calloc_assert(1, sizeof(*iommu));
INIT_LIST_HEAD(&iommu->dma_regions);
iommu->mode = lookup_iommu_mode(iommu_mode);
+ return iommu;
+}
+
+struct iommu *iommu_init(const char *iommu_mode)
+{
+ const char *container_path;
+ struct iommu *iommu;
+ int version;
+
+ iommu = iommu_alloc(iommu_mode);
container_path = iommu->mode->container_path;
if (container_path) {
@@ -449,10 +469,42 @@ struct iommu *iommu_init(const char *iommu_mode)
return iommu;
}
+struct iommu *iommufd_iommu_init(int iommufd, u32 dev_id)
+{
+ struct iommu *iommu;
+
+ iommu = iommu_alloc("iommufd");
+
+ iommu->iommufd = dup(iommufd);
+ VFIO_ASSERT_GT(iommu->iommufd, 0);
+
+ iommu->ioas_id = iommufd_ioas_alloc(iommu->iommufd);
+ iommu->hwpt_id = iommufd_hwpt_alloc(iommu, dev_id);
+
+ return iommu;
+}
+
+static void iommufd_cleanup(struct iommu *iommu)
+{
+ struct iommu_destroy args = {
+ .size = sizeof(args),
+ };
+
+ if (iommu->hwpt_id) {
+ args.id = iommu->hwpt_id;
+ ioctl_assert(iommu->iommufd, IOMMU_DESTROY, &args);
+ }
+
+ args.id = iommu->ioas_id;
+ ioctl_assert(iommu->iommufd, IOMMU_DESTROY, &args);
+
+ VFIO_ASSERT_EQ(close(iommu->iommufd), 0);
+}
+
void iommu_cleanup(struct iommu *iommu)
{
if (iommu->iommufd)
- VFIO_ASSERT_EQ(close(iommu->iommufd), 0);
+ iommufd_cleanup(iommu);
else
VFIO_ASSERT_EQ(close(iommu->container_fd), 0);
diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
index 774d1e90ec0e..81d3879d064f 100644
--- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
@@ -469,15 +469,15 @@ int __vfio_device_bind_iommufd(int device_fd, int iommufd, const char *vf_token)
if (ioctl(device_fd, VFIO_DEVICE_BIND_IOMMUFD, &args))
return -errno;
- return 0;
+ return args.out_devid;
}
-static void vfio_device_bind_iommufd(int device_fd, int iommufd,
- const char *vf_token)
+int vfio_device_bind_iommufd(int device_fd, int iommufd, const char *vf_token)
{
int ret = __vfio_device_bind_iommufd(device_fd, iommufd, vf_token);
- VFIO_ASSERT_EQ(ret, 0, "Failed VFIO_DEVICE_BIND_IOMMUFD ioctl\n");
+ VFIO_ASSERT_GE(ret, 0, "Failed VFIO_DEVICE_BIND_IOMMUFD ioctl\n");
+ return ret;
}
static void vfio_device_attach_iommufd_pt(int device_fd, u32 pt_id)
@@ -503,10 +503,25 @@ static void vfio_pci_iommufd_setup(struct vfio_pci_device *device,
const char *bdf, const char *vf_token)
{
vfio_pci_cdev_open(device, bdf);
- vfio_device_bind_iommufd(device->fd, device->iommu->iommufd, vf_token);
+ device->dev_id = vfio_device_bind_iommufd(device->fd, device->iommu->iommufd, vf_token);
vfio_device_attach_iommufd_pt(device->fd, device->iommu->ioas_id);
}
+void vfio_pci_device_attach_iommu(struct vfio_pci_device *device, struct iommu *iommu)
+{
+ u32 pt_id = iommu->ioas_id;
+
+ /* Only iommufd supports changing struct iommu attachments */
+ VFIO_ASSERT_TRUE(iommu->iommufd);
+
+ if (iommu->hwpt_id)
+ pt_id = iommu->hwpt_id;
+
+ VFIO_ASSERT_NE(pt_id, 0);
+ vfio_device_attach_iommufd_pt(device->fd, pt_id);
+ device->iommu = iommu;
+}
+
struct vfio_pci_device *vfio_pci_device_alloc(const char *bdf, struct iommu *iommu)
{
struct vfio_pci_device *device;
--
2.56.0.rc1.315.gc6ed9934b7-goog