Re: [Qemu-devel] [PATCH v4 2/5] x86: Allow physical address bits to be set

[Eduardo Habkost]

On Fri, Jul 08, 2016 at 08:25:32PM +0100, Dr. David Alan Gilbert wrote:
> > > +            return;
> > > +        }
> > >  
> > > +        if (env->features[FEAT_1_EDX] & CPUID_PSE36) {
> > > +            cpu->phys_bits = 36;
> > > +        } else {
> > > +            cpu->phys_bits = 32;
> > 
> > But TCG_PHYS_ADDR_BITS is still 36. Does this mean TCG
> > reserved-bit handling is broken if pse36 is disabled?
> 
> Good question; I don't understand the TCG code enough to comment;
> but I'm reasonably sure that this patchset doesn't change the behaviour.
> I've booted a 32bit fedora, on a qemu that claims to be running
> with phys_bits = 32 - I don't believe that works on real hardware.
> (Mind you booting it on qemu-system-i386 with qemu32 CPU just doesn't
> work, but it doesn't work before my patch either).

Yes, I was wondering about the existing behavior. You don't
change any behavior here, as far as I can see.

-- 
Eduardo