From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751248AbbASFFb (ORCPT ); Mon, 19 Jan 2015 00:05:31 -0500 Received: from cantor2.suse.de ([195.135.220.15]:43616 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750713AbbASFFa (ORCPT ); Mon, 19 Jan 2015 00:05:30 -0500 Message-ID: <54BC9095.9080506@suse.com> Date: Mon, 19 Jan 2015 06:05:25 +0100 From: Juergen Gross User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: hpa@zytor.com, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, linux-kernel@vger.kernel.org CC: akataria@vmware.com, jongman.heo@samsung.com Subject: Re: [Patch RESEND] x86: don't rely on VMWare emulating PAT MSR correctly References: <1421039745-14335-1-git-send-email-jgross@suse.com> In-Reply-To: <1421039745-14335-1-git-send-email-jgross@suse.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PING! The patch repairs a bug with VMWARE, which has been reported by several users. All of them have confirmed the patch is working. And VMWARE has acked the patch. What else do you need to take it? It is available for over a month now! Juergen On 01/12/2015 06:15 AM, Juergen Gross wrote: > VMWare seems not to emulate the PAT MSR correctly: reaeding > MSR_IA32_CR_PAT returns 0 even after writing another value to it. > > Detect this bug and don't use the read value if it is 0. > > Commit bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 ("x86: Enable PAT to > use cache mode translation tables") triggers this VMWare bug when the > kernel is booted as a VMWare guest. > > Reported-by: Jongman Heo > Signed-off-by: Juergen Gross > Tested-by: Jongman Heo > Acked-by: Alok N Kataria > --- > arch/x86/mm/pat.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c > index edf299c..7ac6869 100644 > --- a/arch/x86/mm/pat.c > +++ b/arch/x86/mm/pat.c > @@ -234,8 +234,13 @@ void pat_init(void) > PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); > > /* Boot CPU check */ > - if (!boot_pat_state) > + if (!boot_pat_state) { > rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); > + if (!boot_pat_state) { > + pat_disable("PAT read returns always zero, disabled."); > + return; > + } > + } > > wrmsrl(MSR_IA32_CR_PAT, pat); > >