From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, "Stephan Bärwolf" <stephan.baerwolf@tu-ilmenau.de>
Subject: Re: [PATCH] KVM: x86 emulator: reject SYSENTER in compatibility mode on AMD guests
Date: Wed, 01 Feb 2012 15:25:55 +0200 [thread overview]
Message-ID: <4F293D63.1080704@redhat.com> (raw)
In-Reply-To: <20120201110044.GA26183@amt.cnet>
On 02/01/2012 01:00 PM, Marcelo Tosatti wrote:
> On Wed, Feb 01, 2012 at 12:27:00PM +0200, Avi Kivity wrote:
> > If the guest thinks it's an AMD, it will not have prepared the SYSENTER MSRs,
> > and if the guest executes SYSENTER in compatibility mode, it will fails.
> >
> > Detect this condition and #UD instead, like the spec says.
>
> Note the SYSENTER_CS & 0xfffc == 0 check protects against a fatal error (unlike
> the SYSCALL bug), in case of zeroed MSRs.
That's a relief. It's still possible for this to fail (say kexec from
32-bit guest to 64-bit guest) but it's incredibly unlikely.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2012-02-01 13:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-01 10:27 [PATCH] KVM: x86 emulator: reject SYSENTER in compatibility mode on AMD guests Avi Kivity
2012-02-01 10:45 ` Stephan Bärwolf
2012-02-01 10:50 ` Avi Kivity
2012-02-01 10:59 ` Stephan Bärwolf
2012-02-01 11:03 ` Avi Kivity
2012-02-01 11:00 ` Marcelo Tosatti
2012-02-01 13:25 ` Avi Kivity [this message]
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