Re: [PATCH] vhost: introduce mdev based hardware backend

[Jason Wang]

On 2019/9/27 äå4:04, Tiwei Bie wrote:
> On Fri, Sep 27, 2019 at 03:14:42PM +0800, Jason Wang wrote:
> > On 2019/9/27 äå12:54, Tiwei Bie wrote:
> > > > > +
> > > > > +		/*
> > > > > +		 * In vhost-mdev, userspace should pass ring addresses
> > > > > +		 * in guest physical addresses when IOMMU is disabled or
> > > > > +		 * IOVAs when IOMMU is enabled.
> > > > > +		 */
> > > > A question here, consider we're using noiommu mode. If guest physical
> > > > address is passed here, how can a device use that?
> > > >
> > > > I believe you meant "host physical address" here? And it also have the
> > > > implication that the HPA should be continuous (e.g using hugetlbfs).
> > > The comment is talking about the virtual IOMMU (i.e. iotlb in vhost).
> > > It should be rephrased to cover the noiommu case as well. Thanks for
> > > spotting this.
> >
> > So the question still, if GPA is passed how can it be used by the
> > virtio-mdev device?
> Sorry if I didn't make it clear..
> Of course, GPA can't be passed in noiommu mode.


I see.

Thanks for the confirmation.


> > Thanks