From: Gleb Natapov <gleb@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "Andre Przywara" <andre@andrep.de>,
kvm@vger.kernel.org, "Jörg Rödel" <joro@8bytes.org>,
"H. Peter Anvin" <hpa@zytor.com>, x86-ml <x86@kernel.org>,
kvm@vger-kernel.org
Subject: Re: [RFC PATCH] Emulate MOVBE
Date: Wed, 10 Apr 2013 13:21:37 +0300 [thread overview]
Message-ID: <20130410102134.GC17919@redhat.com> (raw)
In-Reply-To: <20130410101721.GC13394@pd.tnic>
On Wed, Apr 10, 2013 at 12:17:21PM +0200, Borislav Petkov wrote:
> On Wed, Apr 10, 2013 at 01:08:46PM +0300, Gleb Natapov wrote:
> > We can add the emulation, but we should not start announcing the
> > instruction availability to a guest if host cpu does not have it
> > by default. This may trick a guest into thinking that movbe is the
> > fastest way to do something when it is not.
>
> That could be a problem because kernels compiled for atom look at CPUID
> to check for MOVBE support and refuse to continue if there's none.
>
You will still be able to force it on qemu command line by adding +movbe
to cpu definition, it just not be the default.
--
Gleb.
next prev parent reply other threads:[~2013-04-10 10:21 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-09 23:46 [RFC PATCH] Emulate MOVBE Borislav Petkov
2013-04-10 0:03 ` Borislav Petkov
2013-04-10 0:04 ` H. Peter Anvin
2013-04-10 9:53 ` Borislav Petkov
2013-04-10 9:29 ` Andre Przywara
2013-04-10 10:08 ` Gleb Natapov
2013-04-10 10:17 ` Borislav Petkov
2013-04-10 10:21 ` Gleb Natapov [this message]
2013-04-10 10:39 ` Andre Przywara
2013-04-10 12:16 ` Gleb Natapov
2013-04-11 0:18 ` [PATCH -v2] kvm: " Borislav Petkov
2013-04-11 14:28 ` Gleb Natapov
2013-04-11 15:37 ` Borislav Petkov
2013-04-14 7:41 ` Gleb Natapov
2013-04-14 17:32 ` Borislav Petkov
2013-04-14 18:36 ` H. Peter Anvin
2013-04-14 19:09 ` Borislav Petkov
2013-04-14 19:40 ` H. Peter Anvin
2013-04-16 17:42 ` Gleb Natapov
2013-04-17 11:04 ` Borislav Petkov
2013-04-17 13:38 ` Gleb Natapov
2013-04-17 14:02 ` Borislav Petkov
2013-04-18 22:48 ` Borislav Petkov
2013-04-21 9:46 ` Gleb Natapov
2013-04-21 11:30 ` Borislav Petkov
2013-04-21 12:51 ` Gleb Natapov
2013-04-23 23:41 ` Borislav Petkov
2013-04-23 23:50 ` H. Peter Anvin
2013-04-24 8:42 ` Gleb Natapov
2013-04-24 8:47 ` Borislav Petkov
2013-04-14 8:43 ` Gleb Natapov
2013-04-14 21:02 ` Borislav Petkov
2013-04-16 11:36 ` Paolo Bonzini
2013-04-21 11:46 ` Borislav Petkov
2013-04-21 12:23 ` Borislav Petkov
2013-04-22 8:53 ` Paolo Bonzini
2013-04-22 9:38 ` Borislav Petkov
2013-04-22 9:42 ` Gleb Natapov
2013-04-22 9:52 ` Borislav Petkov
2013-04-22 9:58 ` Gleb Natapov
2013-04-22 13:49 ` Borislav Petkov
2013-04-26 16:08 ` Borislav Petkov
2013-04-16 11:47 ` [RFC PATCH] " Paolo Bonzini
2013-04-16 12:08 ` Borislav Petkov
2013-04-16 12:13 ` H. Peter Anvin
2013-04-16 17:28 ` Gleb Natapov
2013-04-17 10:42 ` Paolo Bonzini
2013-04-17 13:33 ` Gleb Natapov
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