Re: [PATCH v3 7/7] eni_vdpa: add vDPA driver for Alibaba ENI

[Jason Wang]

On Mon, Sep 27, 2021 at 6:36 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> On Sun, Sep 26, 2021 at 12:18:26PM +0800, Jason Wang wrote:
> > > > I wonder if the following can work with ENI:
> > > >
> > > > -device virtio-net-pci,mrg_rxbuf=off
> > > >
> > > > ?
> > >
> > > ENI didn't work.
> > > I will remove F_MRG_RXBUF when get_features.
> >
> > I think we need to fail FEATURE_OK if F_MRG_RXBUF is not negotiated.
> > Since VERSION_1 requires a fixed header length even if F_MRG_RXBUF is
> > not negotiated.
> >
> > But this trick doesn't come for free. If some driver doesn't support
> > mrg_rxbuf, it won't work.
> >
> > Thanks
>
> Yea. Ugh. Down the road I think we'll add legacy support to vdpa on
> strongly ordered systems.

I don't see the connection, can you explain why?

> Doing it in userspace is just too messy imho.
> But yes, this kind of hack is probably ok for weakly ordered systems.
> BTW we need to set VIRTIO_F_ORDER_PLATFORM, right?

Right.

Thanks

>
> --
> MST
>