Re: [PATCH v2 3/6] vfio: selftests: Extend container/iommufd setup for passing vf_token

[David Matlack <dmatlack@google.com>]

On 2025-12-10 06:14 PM, Raghavendra Rao Ananta wrote:
> A UUID is normally set as a vf_token to correspond the VFs with the
> PFs, if they are both bound by the vfio-pci driver. This is true for
> iommufd-based approach and container-based approach. The token can be
> set either during device creation (VFIO_GROUP_GET_DEVICE_FD) in
> container-based approach or during iommu bind (VFIO_DEVICE_BIND_IOMMUFD)
> in the iommu-fd case. Hence extend the functions,
         iommufd

> vfio_pci_iommufd_setup() and vfio_pci_container_setup(), to accept
> vf_token as an (optional) argument and handle the necessary setup.
> 
> No functional changes are expected.
> 
> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> ---
>  tools/testing/selftests/vfio/lib/libvfio.mk   |  4 +-
>  .../selftests/vfio/lib/vfio_pci_device.c      | 45 +++++++++++++++----
>  2 files changed, 40 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/testing/selftests/vfio/lib/libvfio.mk b/tools/testing/selftests/vfio/lib/libvfio.mk
> index b7857319c3f1f..459b14c6885a8 100644
> --- a/tools/testing/selftests/vfio/lib/libvfio.mk
> +++ b/tools/testing/selftests/vfio/lib/libvfio.mk
> @@ -15,6 +15,8 @@ LIBVFIO_C += drivers/ioat/ioat.c
>  LIBVFIO_C += drivers/dsa/dsa.c
>  endif
>  
> +LDLIBS += -luuid
> +
>  LIBVFIO_OUTPUT := $(OUTPUT)/libvfio
>  
>  LIBVFIO_O := $(patsubst %.c, $(LIBVFIO_OUTPUT)/%.o, $(LIBVFIO_C))
> @@ -25,6 +27,6 @@ $(shell mkdir -p $(LIBVFIO_O_DIRS))
>  CFLAGS += -I$(LIBVFIO_SRCDIR)/include
>  
>  $(LIBVFIO_O): $(LIBVFIO_OUTPUT)/%.o : $(LIBVFIO_SRCDIR)/%.c
> -	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
> +	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< $(LDLIBS) -o $@

Do we need $(LDLIBS) when compiling the intermediate .o files? I thought
we would only need it when linking the selftests binaries.

>  
>  EXTRA_CLEAN += $(LIBVFIO_OUTPUT)
> diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> index 9b2a123cee5fc..ac9a5244ddc46 100644
> --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
> @@ -12,6 +12,7 @@
>  #include <sys/mman.h>
>  
>  #include <uapi/linux/types.h>
> +#include <uuid/uuid.h>
>  #include <linux/iommufd.h>
>  #include <linux/limits.h>
>  #include <linux/mman.h>
> @@ -199,7 +200,27 @@ static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf
>  	ioctl_assert(device->group_fd, VFIO_GROUP_SET_CONTAINER, &device->iommu->container_fd);
>  }
>  
> -static void vfio_pci_container_setup(struct vfio_pci_device *device, const char *bdf)
> +static void vfio_pci_group_get_device_fd(struct vfio_pci_device *device,
> +					 const char *bdf, const char *vf_token)
> +{
> +	char arg[64] = {0};

unnecessary intitialization

> +
> +	/*
> +	 * If a vf_token exists, argument to VFIO_GROUP_GET_DEVICE_FD
> +	 * will be in the form of the following example:
> +	 * "0000:04:10.0 vf_token=bd8d9d2b-5a5f-4f5a-a211-f591514ba1f3"
> +	 */
> +	if (vf_token)
> +		snprintf(arg, ARRAY_SIZE(arg), "%s vf_token=%s", bdf, vf_token);

snprintf_assert() :)

> +	else
> +		snprintf(arg, ARRAY_SIZE(arg), "%s", bdf);
> +
> +	device->fd = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, arg);
> +	VFIO_ASSERT_GE(device->fd, 0);
> +}
> +
> +static void vfio_pci_container_setup(struct vfio_pci_device *device,
> +				     const char *bdf, const char *vf_token)
>  {
>  	struct iommu *iommu = device->iommu;
>  	unsigned long iommu_type = iommu->mode->iommu_type;
> @@ -217,8 +238,7 @@ static void vfio_pci_container_setup(struct vfio_pci_device *device, const char
>  	 */
>  	(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);
> +	vfio_pci_group_get_device_fd(device, bdf, vf_token);
>  }
>  
>  static void vfio_pci_device_setup(struct vfio_pci_device *device)
> @@ -279,12 +299,20 @@ const char *vfio_pci_get_cdev_path(const char *bdf)
>  	return cdev_path;
>  }
>  
> -static void vfio_device_bind_iommufd(int device_fd, int iommufd)
> +static void vfio_device_bind_iommufd(int device_fd, int iommufd,
> +				     const char *vf_token)
>  {
>  	struct vfio_device_bind_iommufd args = {
>  		.argsz = sizeof(args),
>  		.iommufd = iommufd,
>  	};
> +	uuid_t token_uuid = {0};

unnecessary intitialization

> +
> +	if (vf_token) {
> +		VFIO_ASSERT_EQ(uuid_parse(vf_token, token_uuid), 0);
> +		args.flags |= VFIO_DEVICE_BIND_FLAG_TOKEN;
> +		args.token_uuid_ptr = (u64)token_uuid;
> +	}
>  
>  	ioctl_assert(device_fd, VFIO_DEVICE_BIND_IOMMUFD, &args);
>  }
> @@ -299,7 +327,8 @@ static void vfio_device_attach_iommufd_pt(int device_fd, u32 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)
> +static void vfio_pci_iommufd_setup(struct vfio_pci_device *device,
> +				   const char *bdf, const char *vf_token)
>  {
>  	const char *cdev_path = vfio_pci_get_cdev_path(bdf);
>  
> @@ -307,7 +336,7 @@ static void vfio_pci_iommufd_setup(struct vfio_pci_device *device, const char *b
>  	VFIO_ASSERT_GE(device->fd, 0);
>  	free((void *)cdev_path);
>  
> -	vfio_device_bind_iommufd(device->fd, device->iommu->iommufd);
> +	vfio_device_bind_iommufd(device->fd, device->iommu->iommufd, vf_token);
>  	vfio_device_attach_iommufd_pt(device->fd, device->iommu->ioas_id);
>  }
>  
> @@ -323,9 +352,9 @@ struct vfio_pci_device *vfio_pci_device_init(const char *bdf, struct iommu *iomm
>  	device->bdf = bdf;
>  
>  	if (iommu->mode->container_path)
> -		vfio_pci_container_setup(device, bdf);
> +		vfio_pci_container_setup(device, bdf, NULL);
>  	else
> -		vfio_pci_iommufd_setup(device, bdf);
> +		vfio_pci_iommufd_setup(device, bdf, NULL);
>  
>  	vfio_pci_device_setup(device);
>  	vfio_pci_driver_probe(device);
> -- 
> 2.52.0.239.gd5f0c6e74e-goog
>