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Re: [Qemu-devel] [PATCH 2/3] push CPUID level to 4 to allow Intel multic
From: |
Andre Przywara |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] push CPUID level to 4 to allow Intel multicore decoding |
Date: |
Tue, 25 Aug 2009 14:21:52 +0200 |
User-agent: |
Thunderbird 2.0.0.21 (X11/20090329) |
Avi Kivity wrote:
> Andre Przywara wrote:
The only problem I can think of is that the advertised cache topology
is somehow bogus and could confuse OSes.
So long as it's smaller than contemporary caches we should be fine.
Oh, I see now that Alex' Core2Duo (on which QEMU's leaf 4 values are
based on) has 4 MB of L2-Cache. Although that is not gigantic for Intel
CPUs, it's certainly too high for many host CPUs. I will lower this
value to say 1MB or 512K to better match the majority of host. I will
send a patch together with some more CPUID reworks I am working on.
btw, does -cpu host use the host cpu cache information?
Good point. It does not, it only deals with leaves 0, 1, 8000_0000 and
8000_0001. I have created a white list of further CPUID leaves which are
safe to propagate to the guest and will also send this in a while.
Thanks for these hints,
Andre.
--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448 3567 12
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[Qemu-devel] [PATCH 1/3] extend -smp parsing to include cores= and threads= options, Andre Przywara, 2009/08/19
[Qemu-devel] [PATCH 3/3] set CPUID bits to present cores and threads topology, Andre Przywara, 2009/08/19