From: Avi Kivity <avi@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Asit K Mallick <asit.k.mallick@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Arjan van de Ven <arjan@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH v2 0/4] Enable SMEP CPU Feature
Date: Tue, 17 May 2011 14:34:01 +0300 [thread overview]
Message-ID: <4DD25D29.9040008@redhat.com> (raw)
In-Reply-To: <20110517104654.GN22093@elte.hu>
On 05/17/2011 01:46 PM, Ingo Molnar wrote:
> >
> > We could support it as a non-default feature, but that reduces its utility.
>
> It would be a nice touch for tools/kvm/: we would use KVM_GET_SREGS and
> KVM_GET_SREGS to twiddle CR4.SMEP, even without the guest explicitly doing it.
>
> A quick glance suggests that it could be done straight away in
> tools/kvm/kvm-cpu.c::kvm_cpu__setup_sregs() during vcpu setup, and hopefully
> that cr4 value survives boot and ends up in the guest kernel's mmu_cr4_features
> mask shadow register.
Depends if the guest uses a read-modify-write pattern or not. We could
do it transparently in kvm.ko, since the real cr4 need not corresponds
to the guest notion (for example, we often set cr0.wp or cr0.ts even
though the guest wants them clear).
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-05-17 11:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-16 21:34 [PATCH v2 0/4] Enable SMEP CPU Feature Fenghua Yu
2011-05-16 21:34 ` [PATCH v2 1/4] x86, cpu: Add CPU flags for SMEP Fenghua Yu
2011-05-17 1:56 ` H. Peter Anvin
2011-05-16 21:34 ` [PATCH v2 2/4] x86, cpu: Add SMEP CPU feature in CR4 Fenghua Yu
2011-05-16 21:34 ` [PATCH v2 3/4] x86, head_32/64.S: Enable SMEP Fenghua Yu
2011-05-17 2:10 ` Matthew Garrett
2011-05-17 23:08 ` Yu, Fenghua
2011-05-17 23:12 ` H. Peter Anvin
2011-05-18 2:57 ` Yu, Fenghua
2011-05-16 21:34 ` [PATCH v2 4/4] x86/kernel/common.c: Disable SMEP by kernel option nosmep Fenghua Yu
2011-05-16 22:01 ` Thomas Gleixner
2011-05-16 21:52 ` [PATCH v2 0/4] Enable SMEP CPU Feature H. Peter Anvin
2011-05-17 7:05 ` Ingo Molnar
2011-05-17 9:15 ` Avi Kivity
2011-05-17 9:29 ` Ingo Molnar
2011-05-17 9:32 ` Avi Kivity
2011-05-17 10:46 ` Ingo Molnar
2011-05-17 11:34 ` Avi Kivity [this message]
2011-05-17 11:38 ` Ingo Molnar
2011-05-17 11:44 ` Avi Kivity
2011-05-17 11:47 ` Avi Kivity
2011-05-17 11:49 ` Pekka Enberg
2011-05-17 11:50 ` Ingo Molnar
2011-05-19 6:10 ` Tian, Kevin
2011-05-19 6:41 ` Shan, Haitao
2011-05-20 8:21 ` Ingo Molnar
2011-05-17 7:03 ` Ingo Molnar
2011-05-17 9:16 ` Avi Kivity
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