Re: [Qemu-devel] [PATCH 2/5] x86: Mask mtrr mask based on CPU physical address limits

[Paolo Bonzini]

On 16/06/2016 21:59, Eduardo Habkost wrote:
> > +                /* The CPU GPs if we write to a bit above the physical 
> > limit of
> > +                 * the host CPU (and KVM emulates that)
> > +                 */
> > +                uint64_t mask = env->mtrr_var[i].mask;
> > +                mask &= phys_mask;
> > +
> 
> We are silently changing the MSR value seen by the guest, should
> we print a warning in case mask != env->mtrr_var[i].mask?

You're right.  post_load is probably a better place to remove these bits
(and to fail if they are not all ones).

Paolo