Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa

[Jason Wang]

在 2022/1/5 下午2:40, Longpeng (Mike, Cloud Infrastructure Service Product 
Dept.) 写道:
> > -----Original Message-----
> > From: Jason Wang [mailto:jasowang@redhat.com]
> > Sent: Wednesday, January 5, 2022 12:36 PM
> > To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> > <longpeng2@huawei.com>
> > Cc: Stefan Hajnoczi <stefanha@redhat.com>; mst <mst@redhat.com>; Stefano
> > Garzarella <sgarzare@redhat.com>; Cornelia Huck <cohuck@redhat.com>; pbonzini
> > <pbonzini@redhat.com>; Gonglei (Arei) <arei.gonglei@huawei.com>; Yechuan
> > <yechuan@huawei.com>; Huangzhichao <huangzhichao@huawei.com>; qemu-devel
> > <qemu-devel@nongnu.org>
> > Subject: Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa
> >
> > On Wed, Jan 5, 2022 at 8:59 AM Longpeng(Mike) <longpeng2@huawei.com> wrote:
> > > From: Longpeng <longpeng2@huawei.com>
> > >
> > > To support generic vdpa deivce, we need add the following ioctls:
> > > - GET_VECTORS_NUM: the count of vectors that supported
> > Does this mean MSI vectors? If yes, it looks like a layer violation:
> > vhost is transport independent.  And it reveals device implementation
> > details which block (cross vendor) migration.
> Can we set the VirtIOPCIProxy.nvectors to "the count of virtqueues + 1 
> (config)" ?


That should work.

Thanks


> > Thanks
> >
> > > - GET_CONFIG_SIZE: the size of the virtio config space
> > > - GET_VQS_NUM: the count of virtqueues that exported
> > >
> > > Signed-off-by: Longpeng <longpeng2@huawei.com>
> > > ---
> > >   linux-headers/linux/vhost.h | 10 ++++++++++
> > >   1 file changed, 10 insertions(+)
> > >
> > > diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h
> > > index c998860d7b..c5edd75d15 100644
> > > --- a/linux-headers/linux/vhost.h
> > > +++ b/linux-headers/linux/vhost.h
> > > @@ -150,4 +150,14 @@
> > >   /* Get the valid iova range */
> > >   #define VHOST_VDPA_GET_IOVA_RANGE      _IOR(VHOST_VIRTIO, 0x78, \
> > >                                               struct vhost_vdpa_iova_range)
> > > +
> > > +/* Get the number of vectors */
> > > +#define VHOST_VDPA_GET_VECTORS_NUM     _IOR(VHOST_VIRTIO, 0x79, int)
> > > +
> > > +/* Get the virtio config size */
> > > +#define VHOST_VDPA_GET_CONFIG_SIZE     _IOR(VHOST_VIRTIO, 0x80, int)
> > > +
> > > +/* Get the number of virtqueues */
> > > +#define VHOST_VDPA_GET_VQS_NUM         _IOR(VHOST_VIRTIO, 0x81, int)
> > > +
> > >   #endif
> > > --
> > > 2.23.0