vfio/pci: Do vf_token checks for VFIO_DEVICE_BIND_IOMMUFD

This was missed during the initial implementation. The VFIO PCI encodes
the vf_token inside the device name when opening the device from the group
FD, something like:

  "0000:04:10.0 vf_token=bd8d9d2b-5a5f-4f5a-a211-f591514ba1f3"

This is used to control access to a VF unless there is co-ordination with
the owner of the PF.

Since we no longer have a device name in the cdev path, pass the token
directly through VFIO_DEVICE_BIND_IOMMUFD using an optional field
indicated by VFIO_DEVICE_BIND_FLAG_TOKEN.

Fixes: 5fcc26969a ("vfio: Add VFIO_DEVICE_BIND_IOMMUFD")
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/0-v3-bdd8716e85fe+3978a-vfio_token_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/device_cdev.c

@@ -60,22 +60,50 @@ static void vfio_df_get_kvm_safe(struct vfio_device_file *df)
 	spin_unlock(&df->kvm_ref_lock);
 }
 
+static int vfio_df_check_token(struct vfio_device *device,
+			       const struct vfio_device_bind_iommufd *bind)
+{
+	uuid_t uuid;
+
+	if (!device->ops->match_token_uuid) {
+		if (bind->flags & VFIO_DEVICE_BIND_FLAG_TOKEN)
+			return -EINVAL;
+		return 0;
+	}
+
+	if (!(bind->flags & VFIO_DEVICE_BIND_FLAG_TOKEN))
+		return device->ops->match_token_uuid(device, NULL);
+
+	if (copy_from_user(&uuid, u64_to_user_ptr(bind->token_uuid_ptr),
+			   sizeof(uuid)))
+		return -EFAULT;
+	return device->ops->match_token_uuid(device, &uuid);
+}
+
 long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
 				struct vfio_device_bind_iommufd __user *arg)
 {
+	const u32 VALID_FLAGS = VFIO_DEVICE_BIND_FLAG_TOKEN;
 	struct vfio_device *device = df->device;
 	struct vfio_device_bind_iommufd bind;
 	unsigned long minsz;
+	u32 user_size;
 	int ret;
 
 	static_assert(__same_type(arg->out_devid, df->devid));
 
 	minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid);
 
-	if (copy_from_user(&bind, arg, minsz))
-		return -EFAULT;
+	ret = get_user(user_size, &arg->argsz);
+	if (ret)
+		return ret;
+	if (user_size < minsz)
+		return -EINVAL;
+	ret = copy_struct_from_user(&bind, minsz, arg, user_size);
+	if (ret)
+		return ret;
 
-	if (bind.argsz < minsz || bind.flags || bind.iommufd < 0)
+	if (bind.iommufd < 0 || bind.flags & ~VALID_FLAGS)
 		return -EINVAL;
 
 	/* BIND_IOMMUFD only allowed for cdev fds */
@@ -93,6 +121,10 @@ long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df,
 		goto out_unlock;
 	}
 
+	ret = vfio_df_check_token(device, &bind);
+	if (ret)
+		goto out_unlock;
+
 	df->iommufd = iommufd_ctx_from_fd(bind.iommufd);
 	if (IS_ERR(df->iommufd)) {
 		ret = PTR_ERR(df->iommufd);

drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c

@@ -1583,6 +1583,7 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/mlx5/main.c

@@ -1372,6 +1372,7 @@ static const struct vfio_device_ops mlx5vf_pci_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/nvgrace-gpu/main.c

@@ -696,6 +696,7 @@ static const struct vfio_device_ops nvgrace_gpu_pci_ops = {
 	.mmap		= nvgrace_gpu_mmap,
 	.request	= vfio_pci_core_request,
 	.match		= vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd	= vfio_iommufd_physical_bind,
 	.unbind_iommufd	= vfio_iommufd_physical_unbind,
 	.attach_ioas	= vfio_iommufd_physical_attach_ioas,
@@ -715,6 +716,7 @@ static const struct vfio_device_ops nvgrace_gpu_pci_core_ops = {
 	.mmap		= vfio_pci_core_mmap,
 	.request	= vfio_pci_core_request,
 	.match		= vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd	= vfio_iommufd_physical_bind,
 	.unbind_iommufd	= vfio_iommufd_physical_unbind,
 	.attach_ioas	= vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/pds/vfio_dev.c

@@ -201,6 +201,7 @@ static const struct vfio_device_ops pds_vfio_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/qat/main.c

@@ -614,6 +614,7 @@ static const struct vfio_device_ops qat_vf_pci_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/vfio_pci.c

@@ -138,6 +138,7 @@ static const struct vfio_device_ops vfio_pci_ops = {
 	.mmap		= vfio_pci_core_mmap,
 	.request	= vfio_pci_core_request,
 	.match		= vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd	= vfio_iommufd_physical_bind,
 	.unbind_iommufd	= vfio_iommufd_physical_unbind,
 	.attach_ioas	= vfio_iommufd_physical_attach_ioas,

drivers/vfio/pci/vfio_pci_core.c

@@ -1821,9 +1821,13 @@ void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_request);
 
-static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
-				      bool vf_token, uuid_t *uuid)
+int vfio_pci_core_match_token_uuid(struct vfio_device *core_vdev,
+				   const uuid_t *uuid)
+
 {
+	struct vfio_pci_core_device *vdev =
+		container_of(core_vdev, struct vfio_pci_core_device, vdev);
+
 	/*
 	 * There's always some degree of trust or collaboration between SR-IOV
 	 * PF and VFs, even if just that the PF hosts the SR-IOV capability and
@@ -1854,7 +1858,7 @@ static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
 		bool match;
 
 		if (!pf_vdev) {
-			if (!vf_token)
+			if (!uuid)
 				return 0; /* PF is not vfio-pci, no VF token */
 
 			pci_info_ratelimited(vdev->pdev,
@@ -1862,7 +1866,7 @@ static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
 			return -EINVAL;
 		}
 
-		if (!vf_token) {
+		if (!uuid) {
 			pci_info_ratelimited(vdev->pdev,
 				"VF token required to access device\n");
 			return -EACCES;
@@ -1880,7 +1884,7 @@ static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
 	} else if (vdev->vf_token) {
 		mutex_lock(&vdev->vf_token->lock);
 		if (vdev->vf_token->users) {
-			if (!vf_token) {
+			if (!uuid) {
 				mutex_unlock(&vdev->vf_token->lock);
 				pci_info_ratelimited(vdev->pdev,
 					"VF token required to access device\n");
@@ -1893,12 +1897,12 @@ static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
 					"Incorrect VF token provided for device\n");
 				return -EACCES;
 			}
-		} else if (vf_token) {
+		} else if (uuid) {
 			uuid_copy(&vdev->vf_token->uuid, uuid);
 		}
 
 		mutex_unlock(&vdev->vf_token->lock);
-	} else if (vf_token) {
+	} else if (uuid) {
 		pci_info_ratelimited(vdev->pdev,
 			"VF token incorrectly provided, not a PF or VF\n");
 		return -EINVAL;
@@ -1906,6 +1910,7 @@ static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(vfio_pci_core_match_token_uuid);
 
 #define VF_TOKEN_ARG "vf_token="
 
@@ -1952,7 +1957,8 @@ int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf)
 		}
 	}
 
-	ret = vfio_pci_validate_vf_token(vdev, vf_token, &uuid);
+	ret = core_vdev->ops->match_token_uuid(core_vdev,
+					       vf_token ? &uuid : NULL);
 	if (ret)
 		return ret;
 

drivers/vfio/pci/virtio/main.c

@@ -94,6 +94,7 @@ static const struct vfio_device_ops virtiovf_vfio_pci_lm_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,
@@ -114,6 +115,7 @@ static const struct vfio_device_ops virtiovf_vfio_pci_tran_lm_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,
@@ -134,6 +136,7 @@ static const struct vfio_device_ops virtiovf_vfio_pci_ops = {
 	.mmap = vfio_pci_core_mmap,
 	.request = vfio_pci_core_request,
 	.match = vfio_pci_core_match,
+	.match_token_uuid = vfio_pci_core_match_token_uuid,
 	.bind_iommufd = vfio_iommufd_physical_bind,
 	.unbind_iommufd = vfio_iommufd_physical_unbind,
 	.attach_ioas = vfio_iommufd_physical_attach_ioas,

include/linux/vfio.h

@@ -105,6 +105,9 @@ struct vfio_device {
  * @match: Optional device name match callback (return: 0 for no-match, >0 for
  *         match, -errno for abort (ex. match with insufficient or incorrect
  *         additional args)
+ * @match_token_uuid: Optional device token match/validation. Return 0
+ *         if the uuid is valid for the device, -errno otherwise. uuid is NULL
+ *         if none was provided.
  * @dma_unmap: Called when userspace unmaps IOVA from the container
  *             this device is attached to.
  * @device_feature: Optional, fill in the VFIO_DEVICE_FEATURE ioctl
@@ -132,6 +135,7 @@ struct vfio_device_ops {
 	int	(*mmap)(struct vfio_device *vdev, struct vm_area_struct *vma);
 	void	(*request)(struct vfio_device *vdev, unsigned int count);
 	int	(*match)(struct vfio_device *vdev, char *buf);
+	int	(*match_token_uuid)(struct vfio_device *vdev, const uuid_t *uuid);
 	void	(*dma_unmap)(struct vfio_device *vdev, u64 iova, u64 length);
 	int	(*device_feature)(struct vfio_device *device, u32 flags,
 				  void __user *arg, size_t argsz);

include/linux/vfio_pci_core.h

@@ -122,6 +122,8 @@ ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *bu
 int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma);
 void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count);
 int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);
+int vfio_pci_core_match_token_uuid(struct vfio_device *core_vdev,
+				   const uuid_t *uuid);
 int vfio_pci_core_enable(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_disable(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev);

include/uapi/linux/vfio.h

@@ -905,10 +905,12 @@ struct vfio_device_feature {
  * VFIO_DEVICE_BIND_IOMMUFD - _IOR(VFIO_TYPE, VFIO_BASE + 18,
  *				   struct vfio_device_bind_iommufd)
  * @argsz:	 User filled size of this data.
- * @flags:	 Must be 0.
+ * @flags:	 Must be 0 or a bit flags of VFIO_DEVICE_BIND_*
  * @iommufd:	 iommufd to bind.
  * @out_devid:	 The device id generated by this bind. devid is a handle for
  *		 this device/iommufd bond and can be used in IOMMUFD commands.
+ * @token_uuid_ptr: Valid if VFIO_DEVICE_BIND_FLAG_TOKEN. Points to a 16 byte
+ *                  UUID in the same format as VFIO_DEVICE_FEATURE_PCI_VF_TOKEN.
  *
  * Bind a vfio_device to the specified iommufd.
  *
@@ -917,13 +919,21 @@ struct vfio_device_feature {
  *
  * Unbind is automatically conducted when device fd is closed.
  *
+ * A token is sometimes required to open the device, unless this is known to be
+ * needed VFIO_DEVICE_BIND_FLAG_TOKEN should not be set and token_uuid_ptr is
+ * ignored. The only case today is a PF/VF relationship where the VF bind must
+ * be provided the same token as VFIO_DEVICE_FEATURE_PCI_VF_TOKEN provided to
+ * the PF.
+ *
  * Return: 0 on success, -errno on failure.
  */
 struct vfio_device_bind_iommufd {
 	__u32		argsz;
 	__u32		flags;
+#define VFIO_DEVICE_BIND_FLAG_TOKEN (1 << 0)
 	__s32		iommufd;
 	__u32		out_devid;
+	__aligned_u64	token_uuid_ptr;
 };
 
 #define VFIO_DEVICE_BIND_IOMMUFD	_IO(VFIO_TYPE, VFIO_BASE + 18)