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From: Andi Kleen <ak@linux.intel.com>
To: Venkatesh Srinivas <venkateshs@google.com>
Cc: Borislav Petkov <bp@alien8.de>,
	Stephane Eranian <eranian@google.com>,
	Linux Kernel Developers List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	mingo@elte.hu, zheng.z.yan@intel.com
Subject: Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
Date: Wed, 23 Apr 2014 13:00:22 -0700	[thread overview]
Message-ID: <20140423200022.GJ8874@tassilo.jf.intel.com> (raw)
In-Reply-To: <CAHdzE-_jJOKo5=m2DAAhaAbDv4Cbq6KaQg4w_tZdofY_wrOWug@mail.gmail.com>

> > Acked-by: Borislav Petkov <bp@suse.de>
> 
> Brown-Paper-Bag-Worn-By: Venkatesh Srinivas <venkateshs@google.com>

Again the bug is really in KVM. We wouldn't need all this crap
if KVM didn't throw the bogus #GPs. I'm sure you missed plenty
of MSR accesses elsewhere, and it's a ticking time bomb.

If the VM lies to the kernel with the family-model you need to at 
least limit the consequences. KVM is spectacularly failing
to do that by throwing bogus #GPs.

The brown paper bad needs to be employed on the KVM code
(or better the bug be fixed there, by defaulting to not #GP
on unknown MSRs)

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

  reply	other threads:[~2014-04-23 20:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-23 17:04 [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage Stephane Eranian
2014-04-23 19:00 ` Borislav Petkov
2014-04-23 19:27   ` Venkatesh Srinivas
2014-04-23 20:00     ` Andi Kleen [this message]
2014-04-24  8:03 ` [tip:perf/urgent] perf/x86: Fix " tip-bot for Stephane Eranian

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