Re: [PATCH net V2 4/4] vhost: log dirty page correctly

[Jason Wang]

On 2018/12/13 äå10:31, Michael S. Tsirkin wrote:
> > Just to make sure I understand this. It looks to me we should:
> >
> > - allow passing GIOVA->GPA through UAPI
> >
> > - cache GIOVA->GPA somewhere but still use GIOVA->HVA in device IOTLB for
> > performance
> >
> > Is this what you suggest?
> >
> > Thanks
> Not really. We already have GPA->HVA, so I suggested a flag to pass
> GIOVA->GPA in the IOTLB.
>
> This has advantages for security since a single table needs
> then to be validated to ensure guest does not corrupt
> QEMU memory.

I wonder how much we can gain through this. Currently, qemu IOMMU gives 
GIOVA->GPA mapping, and qemu vhost code will translate GPA to HVA then 
pass GIOVA->HVA to vhost. It looks no difference to me.

Thanks