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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: Andy Honig <ahonig@google.com>, kvm <kvm@vger.kernel.org>
Subject: Re: KVM: x86: relax MSR_KVM_SYSTEM_TIME alignment check
Date: Fri, 22 Mar 2013 16:47:35 -0300	[thread overview]
Message-ID: <20130322194735.GA21288@amt.cnet> (raw)
In-Reply-To: <20130322192100.GA9382@redhat.com>

On Fri, Mar 22, 2013 at 09:21:00PM +0200, Gleb Natapov wrote:
> On Fri, Mar 22, 2013 at 04:14:07PM -0300, Marcelo Tosatti wrote:
> > 
> > RHEL5 i386 guests register non 32-byte aligned addresses:
> > 
> > kvm-clock: cpu 1, msr 0:3018aa5, secondary cpu clock
> > kvm-clock: cpu 2, msr 0:301f8e9, secondary cpu clock
> > kvm-clock: cpu 3, msr 0:302672d, secondary cpu clock
> > 
> > Check for an address+len that would cross page boundary
> > instead.
> > 
> Ugh. Is there guaranty that it will not register a memory region that
> crosses page boundary or it is pure luck that this does not happen?

Pure build time luck - there is no guarantee that percpu data will not
cross page boundary AFAIK.


  reply	other threads:[~2013-03-22 19:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-22 19:14 KVM: x86: relax MSR_KVM_SYSTEM_TIME alignment check Marcelo Tosatti
2013-03-22 19:21 ` Gleb Natapov
2013-03-22 19:47   ` Marcelo Tosatti [this message]
2013-03-22 21:19     ` KVM: x86: drop alignment checks from KVM_MSR_SYSTEM_TIME address Marcelo Tosatti
2013-03-22 21:57       ` Gleb Natapov
2013-03-23  0:17         ` Andrew Honig
2013-03-23 14:12           ` Gleb Natapov
2013-04-11 16:05             ` Marcelo Tosatti

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