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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <71b4d258-4299-43dd-ec0c-e7a2ab9e128e@redhat.com>
Date: Wed, 14 Jun 2017 15:17:54 +0200
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Subject: Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to
 QEMU cpu_index
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To: Igor Mammedov <imammedo@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>, qemu-devel@nongnu.org, Evgeny Yakovlev <eyakovlev@virtuozzo.com>, "Denis V . Lunev" <den@openvz.org>



On 14/06/2017 15:11, Igor Mammedov wrote:
>> No, KVM really uses the VCPU _index_ for HV_X64_MSR_VP_INDEX:
>
> and as you pointed out that works just by luck,
> as soon as we there would be out of order created CPUs
> returned value won't match cpu_index.
> 
> So instead of spreading this nonsense out to QEMU, is it possible
> to fix kernel(kvm+guest) to use apic_id instead?

Yes, definitely.  At this point let's add a new "KVM_CAP_HYPERV_SYNIC2"
capability and declare the old one broken, that will make things easier.

Paolo