Re: [Qemu-devel] [PATCH 3/5] x86: fill high bits of mtrr mask

[Dr. David Alan Gilbert]

* Paolo Bonzini (address@hidden) wrote:

> Note that the failure mode is pretty brutal since KVM reports an
> internal error right after restarting on the destination, and who knows
> what used to happen before the assertion was introduced.  All MSRs after
> MTRRs would be ignored by KVM!

I think we got lucky because the MTRRs were close to the last MSRs
in the list, there was only some MCG/MCE stuff after it which probably
wouldn't have been missed;  if the MTRR wasn't set I'm guessing someone
would have just had a behaviour that looked like dreadful performance
after migration perhaps?

Dave

> Migrating and checking the configuration complicates the code and,
> because it's only for a warning, doesn't save you from massaging the
> values to make things work.
> 
> Paolo
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK