Re: [PATCH 06/21] vfio/pci: Retrieve preserved device files after Live Update

On Wed, Nov 26, 2025 at 07:35:53PM +0000, David Matlack wrote:

From: Vipin Sharma vipinsh@google.com static int vfio_pci_liveupdate_retrieve(struct liveupdate_file_op_args *args) {

• return -EOPNOTSUPP;

• struct vfio_pci_core_device_ser *ser;
• struct vfio_device *device;
• struct folio *folio;
• struct file *file;
• int ret;
• folio = kho_restore_folio(args->serialized_data);
• if (!folio)

• return -ENOENT;
  

Should this be consistent with the behavior of pci_flb_retrieve() which panics on failure? The short circuit failure paths which follow leak the folio, which seems like a hygiene issue, but the practical significance is moot if vfio_pci_liveupdate_retrieve() failure is catastrophic anyways?

• ser = folio_address(folio);
• device = vfio_find_device(ser, match_device);
• if (!device)

• return -ENODEV;
  

• /*

• * During a Live Update userspace retrieves preserved VFIO cdev files by
  

• * issuing an ioctl on /dev/liveupdate rather than by opening VFIO
  

• * character devices.
  

• *
  

• * To handle that scenario, this routine simulates opening the VFIO
  

• * character device for userspace with an anonymous inode. The returned
  

• * file has the same properties as a cdev file (e.g. operations are
  

• * blocked until BIND_IOMMUFD is called), aside from the inode
  

• * association.
  

• */
  

• file = anon_inode_getfile_fmode("[vfio-device-liveupdate]",

• 			&vfio_device_fops, NULL,
  

• 			O_RDWR, FMODE_PREAD | FMODE_PWRITE);
  

• if (IS_ERR(file)) {

• ret = PTR_ERR(file);
  

• goto out;
  

• }
• ret = __vfio_device_fops_cdev_open(device, file);
• if (ret) {

• fput(file);
  

• goto out;
  

• }
• args->file = file;

+out:

• /* Drop the reference from vfio_find_device() */
• put_device(&device->device);
• return ret;

+}