Re: [Qemu-devel] Re: [PATCHv2 09/12] vhost: vhost net support

[Michael S. Tsirkin]

On Sun, Feb 28, 2010 at 12:45:07PM +0000, Paul Brook wrote:
> > >  There certainly
> > > exist machines that can change physical RAM mapping.
> > 
> > I am talking about mapping between phy RAM offset and qemu virt address.
> > When can it change without RAM in question going away?
> 
> RAM offset or guest physical address? The two are very different.

RAM offset. virtio only cares about where the rings are.

> Some machines have chip selects that allow given physical address range to be 
> mapped to different banks of ram.
> 
> Paul

So guest can cause vhost to write to a wrong place in RAM, but it can
just pass a wrong address directly.  As long as vhost does not access a
non-RAM address, we are definitely fine.

-- 
MST