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Re: [Qemu-devel] [PATCH v4 2/5] x86: Allow physical address bits to be s
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH v4 2/5] x86: Allow physical address bits to be set |
Date: |
Fri, 8 Jul 2016 16:50:57 -0300 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
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
[Qemu-devel] [PATCH v4 3/5] x86: Mask mtrr mask based on CPU physical address limits, Dr. David Alan Gilbert (git), 2016/07/08
[Qemu-devel] [PATCH v4 4/5] x86: fill high bits of mtrr mask, Dr. David Alan Gilbert (git), 2016/07/08
[Qemu-devel] [PATCH v4 5/5] x86: Set physical address bits based on host, Dr. David Alan Gilbert (git), 2016/07/08