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From: Gleb Natapov <gleb@redhat.com>
To: Zachary Amsden <zamsden@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	Jan Kiszka <jan.kiszka@siemens.com>, Avi Kivity <avi@redhat.com>,
	kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH 2/3] KVM: x86: Save&restore interrupt shadow mask
Date: Wed, 17 Feb 2010 11:05:52 +0200	[thread overview]
Message-ID: <20100217090552.GL2995@redhat.com> (raw)
In-Reply-To: <4B7BA374.4040102@redhat.com>

On Tue, Feb 16, 2010 at 10:06:12PM -1000, Zachary Amsden wrote:
> On 02/16/2010 02:39 PM, Marcelo Tosatti wrote:
> >On Mon, Feb 15, 2010 at 10:45:42AM +0100, Jan Kiszka wrote:
> >>The interrupt shadow created by STI or MOV-SS-like operations is part of
> >>the VCPU state and must be preserved across migration. Transfer it in
> >>the spare padding field of kvm_vcpu_events.interrupt.
> 
> STI and MOV-SS interrupt shadow are both treated differently by
> hardware.  Any attempt to unify them into a single field is wrong,
> especially so in a hardware virtualization context, where they are
> actually represented by different fields in the undocumented but
> nevertheless extant format that can be inferred from the hardware
> virtualization context used by specific vendors.
> 
The problem is SVM doesn't distinguish between those two. But we shouldn't
design out interfaces based on SVM brokenness.

--
			Gleb.

  reply	other threads:[~2010-02-17  9:05 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-15  9:45 [PATCH 0/3] KVM: VCPU state extensions Jan Kiszka
2010-02-15  9:45 ` [PATCH 1/3] KVM: x86: Do not return soft events in vcpu_events Jan Kiszka
2010-02-15  9:45 ` [PATCH 2/3] KVM: x86: Save&restore interrupt shadow mask Jan Kiszka
2010-02-17  0:39   ` Marcelo Tosatti
2010-02-17  8:06     ` Zachary Amsden
2010-02-17  9:05       ` Gleb Natapov [this message]
2010-02-17  9:07       ` Jan Kiszka
2010-02-17  9:03     ` Jan Kiszka
2010-02-17  9:10       ` Gleb Natapov
2010-02-17 14:54         ` Marcelo Tosatti
2010-02-19 18:38   ` [PATCH 2/3 v3] " Jan Kiszka
2010-02-15  9:45 ` [PATCH 3/3] KVM: x86: Add support for saving&restoring debug registers Jan Kiszka
2010-02-22 12:34 ` [PATCH 0/3] KVM: VCPU state extensions Jan Kiszka
2010-02-22 12:45   ` Avi Kivity
2010-02-22 12:54     ` Avi Kivity

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