Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Jason Wang]

在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
> On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
> > This patch switch to read virtqueue size from the capability instead
> > of depending on the hardcoded value. This allows the per virtqueue
> > size could be advertised.
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> So let's add an ioctl for this? It's really a bug we don't..


As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM 
actually. Instead it checks the result VHOST_VDPA_SET_VRING_NUM.

So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all 
the virtqueues.

If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it 
will have a user or not.

Thanks


> > ---
> >   drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > index 2926641fb586..198f7076e4d9 100644
> > --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> > +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > @@ -18,7 +18,6 @@
> >   #include <linux/virtio_pci.h>
> >   #include <linux/virtio_pci_modern.h>
> >   
> > -#define VP_VDPA_QUEUE_MAX 256
> >   #define VP_VDPA_DRIVER_NAME "vp_vdpa"
> >   #define VP_VDPA_NAME_SIZE 256
> >   
> > @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> >   
> >   static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
> >   {
> > -	return VP_VDPA_QUEUE_MAX;
> > +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
> > +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
> > +
> > +	return vp_modern_get_queue_size(mdev, qid);
> >   }
> >   
> >   static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
> > --
> > 2.25.1