Re: [PATCH 7/8] KVM: x86: avoid logical_map when it is invalid

[Radim KrÄmÃÅ]

2015-01-30 10:19+0100, Paolo Bonzini:
> On 29/01/2015 22:48, Radim KrÄmÃÅ wrote:
> > We want to support mixed modes and the easiest solution is to avoid
> > optimizing those weird and unlikely scenarios.
> 
> Hmm, what happens if use maxcpus to disable some CPUs at startup?

Their APICs are kept sw-disabled in xAPIC mode.

>                                                                    Could
> the disabled CPUs remain in xapic mode while the others move to x2apic?

Yes, but it would only matter if the OS set LDR on them.
I mark x2APIC with perfectly configured xAPIC on unused processors as
"weird" ... (Linux 3.18 and 2.6.32 doesn't do it.)
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