On 2026/03/11 11:50, Vivek Kasireddy wrote:
In addition to memfd, a blob resource can also have its backing
storage in a VFIO device region. Since, there is no effective way
to determine where the backing storage is located, we first try to
create a dmabuf assuming it is in memfd. If that fails, we try to
create a dmabuf assuming it is in VFIO device region.
So, we first call virtio_gpu_create_udmabuf() to check if the blob's
backing storage is located in a memfd or not. If it is not, we invoke
the vfio_device_create_dmabuf_fd() API which identifies the right
VFIO device and eventually creates a dmabuf fd.
Note that, for mmapping the dmabuf, we directly call mmap() if the
dmabuf fd was created via virtio_gpu_create_udmabuf() since we know
that the udmabuf driver supports mmap(). However, if the dmabuf was
created via vfio_device_create_dmabuf_fd(), we use the
vfio_device_mmap_dmabuf() API to get a mapping for the dmabuf.
Cc: Marc-André Lureau <[email protected]>
Cc: Alex Bennée <[email protected]>
Cc: Akihiko Odaki <[email protected]>
Cc: Dmitry Osipenko <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Cédric Le Goater <[email protected]>
Signed-off-by: Vivek Kasireddy <[email protected]>
Now I think this patch implements proper handling of all error
conditions and conforms the convention.
Reviewed-by: Akihiko Odaki <[email protected]>
