Re: [PATCH v2 19/24] vdpa: make sure set_features in invoked for legacy

[Jason Wang]

On 2020/8/5 下午7:40, Michael S. Tsirkin wrote:
> On Wed, Aug 05, 2020 at 02:14:07PM +0800, Jason Wang wrote:
> > On 2020/8/4 上午5:00, Michael S. Tsirkin wrote:
> > > Some legacy guests just assume features are 0 after reset.
> > > We detect that config space is accessed before features are
> > > set and set features to 0 automatically.
> > > Note: some legacy guests might not even access config space, if this is
> > > reported in the field we might need to catch a kick to handle these.
> > I wonder whether it's easier to just support modern device?
> >
> > Thanks
> Well hardware vendors are I think interested in supporting legacy
> guests. Limiting vdpa to modern only would make it uncompetitive.


My understanding is that, IOMMU_PLATFORM is mandatory for hardware vDPA 
to work. So it can only work for modern device ...

Thanks


>