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Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index |
Date: |
Wed, 14 Jun 2017 15:00:27 +0200 |
On Wed, 14 Jun 2017 13:26:44 +0200
Paolo Bonzini <address@hidden> wrote:
> On 14/06/2017 13:25, Roman Kagan wrote:
> >> The problem with that is that it will break as soon as we create
> >> VCPUs in a different order. Unsolvable on hosts that don't allow
> >> HV_X64_MSR_VP_INDEX to be set, however.
> > Right, thanks for putting together a detailed explanation.
> >
> > This was a thinko back then, not to have HV_X64_MSR_VP_INDEX maintained
> > by QEMU. I'm going to post a patch to KVM fixing that.
> >
> > Meanwhile QEMU needs a way to maintain its notion of vp_index that is
> > 1) in sync with kernel's notion
> > 2) also with kernels that don't support setting the msr
> > 3) persistent across migrations
> >
> > cpu_index looked like a perfect candidate.
> >
>
> What you want is the APIC id,
> which _is_ cpu_index but may not be in the
depending on topology cpu_index won't be the same as APIC ID/vcpu_id
/AMDs odd core count/.
> future. But the APIC id is also the KVM vcpu_id, so there's no need to
> have VP_INDEX maintained by QEMU.
agreed it'd be better to reuse vcpu_id/apic id as interface between
qemu/kvm/guest instead of adding additional cpu_index concept in ABI
>
> Paolo
- [Qemu-devel] [PATCH 00/23] hyperv fixes and enhancements, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 04/23] hyperv: ensure msrs are inited properly, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 03/23] hyperv: set partition-wide MSRs only on first vcpu, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 01/23] hyperv: add header with protocol definitions, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 02/23] update-linux-headers: prepare for hyperv.h removal, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 06/23] hyperv: helper to find vcpu by VP index, Roman Kagan, 2017/06/06
- [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Roman Kagan, 2017/06/06
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Eduardo Habkost, 2017/06/13
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Roman Kagan, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Paolo Bonzini, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index,
Igor Mammedov <=
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Roman Kagan, 2017/06/15
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Paolo Bonzini, 2017/06/15
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Igor Mammedov, 2017/06/15
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Roman Kagan, 2017/06/15
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Eduardo Habkost, 2017/06/18
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Eduardo Habkost, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Igor Mammedov, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Paolo Bonzini, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Eduardo Habkost, 2017/06/14
- Re: [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index, Paolo Bonzini, 2017/06/14