The virtio-blk-vhost-vdpa driver in libblkio 1.3.0 supports the fd passing through the new 'fd' property.
Since now we are using qemu_open() on '@path' if the virtio-blk driver supports the fd passing, let's announce it. In this way, the management layer can pass the file descriptor of an already opened vhost-vdpa character device. This is useful especially when the device can only be accessed with certain privileges. Add the '@fdset' feature only when the virtio-blk-vhost-vdpa driver in libblkio supports it. Suggested-by: Markus Armbruster <arm...@redhat.com> Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> --- Notes: v5: - moved `features` to the object level to simplify libvirt code [Jonathon] - wrapped a line too long in the documentation [Markus] v4: - added this patch to allow libvirt to discover we support fdset [Markus] meson.build | 4 ++++ qapi/block-core.json | 6 ++++++ 2 files changed, 10 insertions(+) diff --git a/meson.build b/meson.build index 2d48aa1e2e..4a9fa4c435 100644 --- a/meson.build +++ b/meson.build @@ -2106,6 +2106,10 @@ config_host_data.set('CONFIG_LZO', lzo.found()) config_host_data.set('CONFIG_MPATH', mpathpersist.found()) config_host_data.set('CONFIG_MPATH_NEW_API', mpathpersist_new_api) config_host_data.set('CONFIG_BLKIO', blkio.found()) +if blkio.found() + config_host_data.set('CONFIG_BLKIO_VHOST_VDPA_FD', + blkio.version().version_compare('>=1.3.0')) +endif config_host_data.set('CONFIG_CURL', curl.found()) config_host_data.set('CONFIG_CURSES', curses.found()) config_host_data.set('CONFIG_GBM', gbm.found()) diff --git a/qapi/block-core.json b/qapi/block-core.json index 98d9116dae..4bf89171c6 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -3955,10 +3955,16 @@ # # @path: path to the vhost-vdpa character device. # +# Features: +# @fdset: Member @path supports the special "/dev/fdset/N" path +# (since 8.1) +# # Since: 7.2 ## { 'struct': 'BlockdevOptionsVirtioBlkVhostVdpa', 'data': { 'path': 'str' }, + 'features': [ { 'name' :'fdset', + 'if': 'CONFIG_BLKIO_VHOST_VDPA_FD' } ], 'if': 'CONFIG_BLKIO' } ## -- 2.40.1