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Date: Mon, 27 May 2013 15:14:25 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] target-i386: Disable CPUID_EXT_MONITOR
	when KVM is enabled
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To: Eduardo Habkost <ehabkost@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>, Bandan Das <bsd@redhat.com>, qemu-devel@nongnu.org, =?ISO-8859-1?Q?Andreas_F=E4rber?= <afaerber@suse.de>

Il 27/05/2013 15:07, Eduardo Habkost ha scritto:
>> Changing TCG to KVM should not change hardware
>> > if you use "-cpu ...,enforce", so it is right that it fails when
>> > starting with KVM.
>> > 
> Changing between KVM and TCG _does_ change hardware, today (with or
> without check/enforce). All CPU models on TCG have features not
> supported by TCG automatically removed. See the "if (!kvm_enabled())"
> block at x86_cpu_realizefn().

Perhaps (for "-cpu ...,enforce" or check) that's the real bug we have to
fix?

Paolo

> (That's why I argue that we need separate classes/names for TCG and KVM
> modes. Otherwise our predefined models get less useful as they will
> require low-level feature-bit fiddling on the libvirt side to make them
> work as expected.)
>