Re: [Qemu-devel] [PATCH] vhost-vsock: support parse mergeable feature

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Dec 14, 2018 at 05:43:28PM +0800, jiangyiwen wrote:
> On 2018/12/13 22:54, Michael S. Tsirkin wrote:
> > On Thu, Dec 13, 2018 at 11:27:24AM +0800, jiangyiwen wrote:
> >> On 2018/12/12 21:19, Michael S. Tsirkin wrote:
> >>> On Wed, Dec 12, 2018 at 05:54:49PM +0800, jiangyiwen wrote:
> >>>> Currently vhost-vsock doesn't have any feature bits, so it
> >>>> don't support parse mergeable rx buffer feature. And the
> >>>> feature is support in another series of patches named
> >>>> "VSOCK: support mergeable rx buffer in vhost-vsock".
> >>>>
> >>>> So we neet to support parse mergeable feature in vhost-vsock
> >>>> if above patches are merged.
> >>>>
> >>>> Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com>
> >>>
> >>> OK but what does it do? this just defines the feature bit ...
> >>> Also pls copy virtio-dev whenever you change the host/guest
> >>> interface.
> >>>
> >>> Thanks!
> >>>
> >>
> >> Hi Michael,
> >>
> >> In my opinion, for vhost device, device feature bits need to be
> >> intersected between vhost and qemu, so I add mergeable rx buffer feature
> >> into vdev->host_features, and then intersected with vhost_dev features.
> >>
> >> Later if someone want to add new feature, it can use virtio_add_feature()
> >> in vhost_vsock_get_features().
> >>
> >> Thanks,
> >> Yiwen.
> > 
> > I understand. Sorry.  It seems that your patchset wasn't threaded
> > properly, each patch was by its own. Can you pls take a look at fixing
> > that?
> > 
> 
> Hi Michael,
> 
> Thanks your suggestions, I want to how to send patch when
> patch involving multiple communities, like qemu
> and linux kernel. In this case, how should we send them?
> 
> Thanks,
> Yiwen.


Both use the same threading so just copy both.


> >>>> ---
> >>>>  hw/virtio/vhost-vsock.c                       | 9 +++++++--
> >>>>  include/standard-headers/linux/virtio_vsock.h | 3 +++
> >>>>  2 files changed, 10 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
> >>>> index aa5af92..5023c05 100644
> >>>> --- a/hw/virtio/vhost-vsock.c
> >>>> +++ b/hw/virtio/vhost-vsock.c
> >>>> @@ -178,8 +178,13 @@ static uint64_t vhost_vsock_get_features(VirtIODevice *vdev,
> >>>>                                           uint64_t requested_features,
> >>>>                                           Error **errp)
> >>>>  {
> >>>> -    /* No feature bits used yet */
> >>>> -    return requested_features;
> >>>> +    VHostVSock *vsock = VHOST_VSOCK(vdev);
> >>>> +    uint64_t features;
> >>>> +
> >>>> +    virtio_add_feature(&requested_features, VIRTIO_VSOCK_F_MRG_RXBUF);
> >>>> +    features = requested_features & vsock->vhost_dev.features;
> >>>> +
> >>>> +    return features;
> >>>>  }
> >>>>
> >>>>  static void vhost_vsock_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> >>>> diff --git a/include/standard-headers/linux/virtio_vsock.h b/include/standard-headers/linux/virtio_vsock.h
> >>>> index be44321..4c583ec 100644
> >>>> --- a/include/standard-headers/linux/virtio_vsock.h
> >>>> +++ b/include/standard-headers/linux/virtio_vsock.h
> >>>> @@ -38,6 +38,9 @@
> >>>>  #include "standard-headers/linux/virtio_ids.h"
> >>>>  #include "standard-headers/linux/virtio_config.h"
> >>>>
> >>>> +/* Virtio-vsock feature */
> >>>> +#define VIRTIO_VSOCK_F_MRG_RXBUF 0 /* Host can merge receive buffers. */
> >>>> +
> >>>>  struct virtio_vsock_config {
> >>>>  	uint64_t guest_cid;
> >>>>  } QEMU_PACKED;
> >>>> -- 
> >>>> 1.8.3.1
> >>>>
> >>>
> >>> .
> >>>
> >>
> > 
> > .
> > 
>