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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>,
	"Raslan, KarimAllah" <karahmed@amazon.de>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"x86@kernel.org" <x86@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"rkrcmar@redhat.com" <rkrcmar@redhat.com>
Subject: Re: [PATCH 2/2] kvm: nVMX: Introduce KVM_CAP_STATE
Date: Fri, 27 Apr 2018 12:03:21 +0200	[thread overview]
Message-ID: <f8875546-da53-fc36-d3da-5b5ff089ccc0@redhat.com> (raw)
In-Reply-To: <CALMp9eS6D4pfbGEfcz7MpRncTte5weUJE9g-C_qMVxnaGd+RtQ@mail.gmail.com>

On 27/04/2018 00:28, Jim Mattson wrote:
> The other thing that comes to mind is that there are some new fields
> in the VMCS12 since I first implemented this. One potentially
> troublesome field is the VMX preemption timer. If the current timer
> value is not saved on VM-exit, then it won't be stashed in the shadow
> VMCS12 by sync_vmcs12. Post-migration, the timer will be reset to its
> original value.
> 
> Do we care? Is this any different from what happens on real hardware
> when there's an SMI? According to the SDM, this appears to be exacty
> what happens when the dual-monitor treatment of SMIs and SMM is
> active, but it's not clear what happens with the default treatment of
> SMIs and SMM.

I think it should be the same, because the preemption timer countdown is
not part of the VMX-critical state.

Paolo

  reply	other threads:[~2018-04-27 10:03 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-12 15:12 [PATCH 1/2] X86/KVM: Properly restore 'tsc_offset' when running an L2 guest KarimAllah Ahmed
2018-04-12 15:12 ` [PATCH 2/2] kvm: nVMX: Introduce KVM_CAP_STATE KarimAllah Ahmed
2018-04-12 16:39   ` Paolo Bonzini
2018-04-14 15:56   ` Raslan, KarimAllah
2018-04-14 22:31     ` Raslan, KarimAllah
2018-04-16 16:22   ` Jim Mattson
2018-04-16 17:15     ` Raslan, KarimAllah
2018-04-26 22:28       ` Jim Mattson
2018-04-27 10:03         ` Paolo Bonzini [this message]
2018-04-27 15:19           ` Jim Mattson
2018-04-28  0:42             ` Paolo Bonzini
2018-04-12 16:35 ` [PATCH 1/2] X86/KVM: Properly restore 'tsc_offset' when running an L2 guest Paolo Bonzini
2018-04-12 17:04   ` Raslan, KarimAllah
2018-04-12 17:21     ` Raslan, KarimAllah
2018-04-12 20:21       ` Paolo Bonzini
2018-04-12 20:24         ` Raslan, KarimAllah

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