Re: [Qemu-devel] [PATCH v4 0/2] virtio: Move host features to backends

[Peter Maydell]

On 28 April 2015 at 12:51,  <address@hidden> wrote:
> From: Shannon Zhao <address@hidden>
>
> The reason to do this is that the virtio-net-device can't expose host
> features to guest while using virtio-mmio. So the performance is low.
>
> The virtio-*-pci, virtio-*-s390, and virtio-*-ccw already have the
> ability to forward property accesses to the backend child, by calling
> *_virtio_*_instance_init -> qdev_alias_all_properties. So if we move the
> host features to backends, it doesn't break the backwards compatibility
> for virtio-*-pci, virtio-*-s390, and virtio-*-ccw.
>
> Here we move the host features to backends, involving
> DEFINE_VIRTIO_NET_FEATURES, DEFINE_VIRTIO_SCSI_FEATURES. So the
> virtio-mmio devices could have the host freatures, and this has a great
> performance improvement to virtio-mmio, especially to virtio-net-device.

Reviewed-by: Peter Maydell <address@hidden>

(but not tested :-))

thanks
-- PMM