On Wed, Aug 03 2022, Stefan Hajnoczi <stefa...@redhat.com> wrote:
> Suggested-by: Cornelia Huck <coh...@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> include/hw/virtio/virtio.h | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index db1c0ddf6b..8d27fe1824 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -120,9 +120,29 @@ struct VirtioDeviceClass {
> /* This is what a VirtioDevice must implement */
> DeviceRealize realize;
> DeviceUnrealize unrealize;
> +
> + /**
> + * get_features:
> + * @vdev: the VirtIODevice
> + * @requested_features: existing device feature bits from
> + * vdev->host_features
> + * @errp: pointer to error object
> + *
> + * Get the device feature bits.
> + *
> + * The ->get_features() function typically sets always-on device feature
> + * bits as well as conditional feature bits that require some logic to
> + * compute.
> + *
> + * Device feature bits can also be set in vdev->host_features before this
> + * function is called using DEFINE_PROP_BIT64() qdev properties.
> + *
> + * Returns: the final device feature bits to store in
> vdev->host_features.
> + */
Not sure if we want to go full function doc for features, as none of the
other callbacks have it...
I thought about something like
"Called with vdev->host_features in requested_features. Returns device
feature bits to be stored in vdev->host_features after factoring in
device-specific feature bits."
The important part IMHO is that requested_features contains
vdev->host_features, so no need to merge them in.
> uint64_t (*get_features)(VirtIODevice *vdev,
> uint64_t requested_features,
> Error **errp);
> +
> uint64_t (*bad_features)(VirtIODevice *vdev);
> void (*set_features)(VirtIODevice *vdev, uint64_t val);
> int (*validate_features)(VirtIODevice *vdev);
