[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Bug with TARGET_PHYS_ADDR_SPACE_BITS
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] Bug with TARGET_PHYS_ADDR_SPACE_BITS |
Date: |
Wed, 20 Aug 2008 08:15:58 +0200 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Tue, Aug 19, 2008 at 07:46:50PM +0200, Chris Lalancette wrote:
> Hello,
> oVirt is currently using straight x86_64 qemu emulation for certain parts
> of the architecture (we mostly use KVM, but need to use full emulation for a
> couple of parts). We recently upgraded our userspace package to kvm-72, but
> found that we could not PXE boot guests when we were doing full emulation
> (under
> kvm, we could PXE boot just fine). We also tried using qemu SVN tip, with
> similar results. We ended up doing a bisect, and tracked down the problem to
> this commit (from the kvm repo, but pulled from qemu):
>
> http://git.kernel.org/?p=linux/kernel/git/amit/kvm-userspace.git;a=commit;h=468f7507339a5236bff8ab339eb0c1b019a95fda
>
> The important changes in there in terms of this bug revolves around
> TARGET_PHYS_ADDR_SPACE_BITS in exec.c. If I change that back to 32 (what it
> was
> before this patch for x86_64), the PXE boot succeeds. Also, if I remove
> TARGET_PHYS_ADDR_SPACE_BITS > 32 conditional code in phys_page_find_alloc(),
> but
> leave TARGET_PHYS_ADDR_SPACE_BITS as 42, the PXE boot also works. I can't
> claim
> to understand the conditional code I've compiled out, so I'm not sure where
> the
> bug would be. Does anyone have an idea what the problem might be?
>
Are you using qemu or qemu-system-x86_64? Could you also build qemu with
--disable-kqemu? It possible that kqemu support is causing this problem,
as it is limited to 32 bits.
I have tested support for PAE with various guests, including memtest86,
and haven't encountered any problem.
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' address@hidden | address@hidden
`- people.debian.org/~aurel32 | www.aurel32.net