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Re: [Qemu-devel] [PATCH v2 0/3] target-i386: Don't trigger CPUID warning
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/3] target-i386: Don't trigger CPUID warnings by default in KVM mode (in most hosts) |
Date: |
Wed, 4 Nov 2015 11:50:25 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 03/11/2015 23:54, Eduardo Habkost wrote:
> Probably, yes. libvirt even has these commented out in their cpu_map.xml:
>
> <model name='qemu64'>
> <model name='kvm64'/>
> <!-- These are supported only by TCG. KVM supports them only if the
> host does. So we leave them out:
>
> <feature name='popcnt'/>
> <feature name='lahf_lm'/>
> <feature name='sse4a'/>
> <feature name='abm'/>
> -->
> <feature name='svm'/>
> </model>
>
> (libvirt must stop making assumptions about the CPU model feature sets so
> all <feature> elements in cpu_map.xml should go away. But at least the
> current cpu_map.xml is a good reference to what it expects today.)
FWIW, lahf_lm is present on virtually all 64-bit machines and is rare
enough that KVM could just emulate it, so we shouldn't remove it. But
removing popcnt is a good suggestion to take from libvirt. It can be
done on top of this series. We should get all of this into the first
-rc, anyway.
Paolo