Re: [Qemu-devel] [PATCH V1 1/1] tests: Add migration test for aarch64

[Dr. David Alan Gilbert]

* Peter Maydell (address@hidden) wrote:
> On 26 January 2018 at 19:46, Dr. David Alan Gilbert <address@hidden> wrote:
> > * Peter Maydell (address@hidden) wrote:
> >> I think the correct fix here is that your test code should turn
> >> its MMU on. Trying to treat guest RAM as uncacheable doesn't work
> >> for Arm KVM guests (for the same reason that VGA device video memory
> >> doesn't work). If it's RAM your guest has to arrange to map it as
> >> Normal Cacheable, and then everything should work fine.
> >
> > Does this cause problems with migrating at just the wrong point during
> > a VM boot?
> 
> It wouldn't surprise me if it did, but I don't think I've ever
> tried to provoke that problem...

If you think it'll get the RAM contents wrong, it might be best to fail
the migration if you can detect the cache is disabled in the guest.

Dave

> thanks
> -- PMM
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK