Re: [PATCH v5 00/15] vDPA shadow virtqueue

[Michael S. Tsirkin]

On Tue, Mar 08, 2022 at 04:20:53PM +0800, Jason Wang wrote:
> > Not by itself but I'm not sure we can guarantee guest will not
> > attempt to use the IOVA addresses we are reserving down
> > the road.
> 
> The IOVA is allocated via the listeners and stored in the iova tree
> per GPA range as IOVA->(GPA)->HVA.Guests will only see GPA, Qemu
> virtio core see GPA to HVA mapping. And we do a reverse lookup to find
> the HVA->IOVA we allocated previously.  So we have double check here:
> 
> 1) Qemu memory core to make sure the GPA that guest uses is valid
> 2) the IOVA tree that guarantees there will be no HVA beyond what
> guest can see is used
> 
> So technically, there's no way for the guest to use the IOVA address
> allocated for the shadow virtqueue.
> 
> Thanks

I mean, IOVA is programmed in the host hardware to translate to HPA, right?

-- 
MST