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Re: [PATCH v5] x86: call smp vmxoff in smp stop

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On 19.04.2017 18:18, Paolo Bonzini wrote:
> From: Tiantian Feng <fengtiantian@huawei.com>
> 
> A CPU in VMX root mode will ignore INIT signals and fail to bring
> up the APs after reboot.  Therefore, on a panic we disable VMX on all
> CPUs before rebooting or triggering kdump.
> 
> Do this when halting the machine as well, in case a firmware-level reboot
> does not perform a cold reset for all processors.  Without doing this,
> rebooting the host may hang.

Guess this make sense, just wonder if something like that is actually
expected to work? Not doing a cold reset feels like leaving a lot of
stuff in an uninitialized state. Shouldn't that specific firmware then
care about performing any necessary resets?

-- 

Thanks,

David

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[PATCH v5] x86: call smp vmxoff in smp stop Paolo Bonzini <pbonzini@redhat.com> - 2017-04-19 18:20 +0200
  Re: [PATCH v5] x86: call smp vmxoff in smp stop David Hildenbrand <david@redhat.com> - 2017-04-20 12:10 +0200
    Re: [PATCH v5] x86: call smp vmxoff in smp stop Paolo Bonzini <pbonzini@redhat.com> - 2017-04-20 12:20 +0200
      Re: [PATCH v5] x86: call smp vmxoff in smp stop David Hildenbrand <david@redhat.com> - 2017-04-20 13:10 +0200
  [tip:x86/boot] x86/reboot: Turn off KVM when halting a CPU tip-bot for Tiantian Feng <tipbot@zytor.com> - 2017-04-20 13:30 +0200

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