From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] KVM: SVM: Emulate next_rip svm feature
Date: Wed, 28 Jul 2010 14:18:22 +0200 [thread overview]
Message-ID: <20100728121822.GH26098@amd.com> (raw)
In-Reply-To: <4C501B30.6020900@redhat.com>
On Wed, Jul 28, 2010 at 07:57:36AM -0400, Avi Kivity wrote:
> If the instruction opcode is on mmio, the processor never sees the
> opcode and thus can not intercept. Or the processor may see one
> instruction, which is not intercepted, but by the time the emulator
> kicks in a different instruction takes its place, since another vcpu is
> evilly cross-modifying the code.
Right. X-modifying code is a problem too.
> The guest (L2 in this case) is doomed since it execution cannot
> continue. But L1 and L0 are fine. The problem with L2 avoiding
> intercepts is that L2 can change control registers and take over L1.
Right too. We can not ignore it. The right fix is probably a check for
the instruction intercepts right after the decoder has run and before
the emulator ran.
Joer
--
Joerg Roedel - AMD Operating System Research Center
Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632
next prev parent reply other threads:[~2010-07-28 12:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-27 16:14 [PATCH 0/2] Nested SVM fix and next_rip emulation Joerg Roedel
2010-07-27 16:14 ` [PATCH 1/2] KVM: SVM: Sync efer back into nested vmcb Joerg Roedel
2010-07-27 19:07 ` Avi Kivity
2010-07-28 7:54 ` Roedel, Joerg
2010-07-27 16:14 ` [PATCH 2/2] KVM: SVM: Emulate next_rip svm feature Joerg Roedel
2010-07-27 18:32 ` Avi Kivity
2010-07-28 9:37 ` Roedel, Joerg
2010-07-28 10:28 ` Avi Kivity
2010-07-28 11:25 ` Roedel, Joerg
2010-07-28 11:34 ` Avi Kivity
2010-07-28 11:51 ` Roedel, Joerg
2010-07-28 11:57 ` Avi Kivity
2010-07-28 12:18 ` Roedel, Joerg [this message]
2010-07-28 12:25 ` Avi Kivity
2010-07-28 10:28 ` [PATCH 0/2] Nested SVM fix and next_rip emulation Avi Kivity
2010-07-28 16:53 ` Marcelo Tosatti
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