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Re: [Qemu-devel] [PATCH build-fix] target-i386: emulate CPUID level of r
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH build-fix] target-i386: emulate CPUID level of real hardware |
Date: |
Wed, 15 Jul 2015 17:12:26 -0300 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, Jul 09, 2015 at 09:07:39PM +0200, Radim Krčmář wrote:
> W10 insider has a bug where it ignores CPUID level and interprets
> CPUID.(EAX=07H, ECX=0H) incorrectly, because CPUID in fact returned
> CPUID.(EAX=04H, ECX=0H); this resulted in execution of unsupported
> instructions.
>
> While it's a Windows bug, there is no reason to emulate incorrect level.
>
> I used http://instlatx64.atw.hu/ as a source of CPUID and checked that
> it matches Penryn Xeon X5472, Westmere Xeon W3520, SandyBridge i5-2540M,
> and Haswell i5-4670T.
>
> kvm64 and qemu64 were bumped to 0xD to allow all available features for
> them (and to avoid the same Windows bug).
>
> Signed-off-by: Radim Krčmář <address@hidden>
> Reviewed-by: Eduardo Habkost <address@hidden>
> Signed-off-by: Eduardo Habkost <address@hidden>
Thanks, applied to x86 tree. As the existing code prevents a guest OS
from running, I consider it a bug fix.
--
Eduardo
- [Qemu-devel] [PULL 0/3] X86 queue, 2015-07-03, Eduardo Habkost, 2015/07/03
- [Qemu-devel] [PULL 1/3] i386: Introduce ARAT CPU feature, Eduardo Habkost, 2015/07/03
- [Qemu-devel] [PULL 2/3] target-i386: avoid overflow in the tsc-frequency property, Eduardo Habkost, 2015/07/03
- [Qemu-devel] [PULL 3/3] target-i386: emulate CPUID level of real hardware, Eduardo Habkost, 2015/07/03
- Re: [Qemu-devel] [PULL 0/3] X86 queue, 2015-07-03, Andreas Färber, 2015/07/03
- Re: [Qemu-devel] [PULL 0/3] X86 queue, 2015-07-03, Peter Maydell, 2015/07/05