From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F27CFC4BA06 for ; Wed, 26 Feb 2020 00:43:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAD2321D7E for ; Wed, 26 Feb 2020 00:43:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728989AbgBZAnA (ORCPT ); Tue, 25 Feb 2020 19:43:00 -0500 Received: from mga17.intel.com ([192.55.52.151]:7560 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728865AbgBZAnA (ORCPT ); Tue, 25 Feb 2020 19:43:00 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Feb 2020 16:42:59 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,486,1574150400"; d="scan'208";a="438247953" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by fmsmga006.fm.intel.com with ESMTP; 25 Feb 2020 16:42:58 -0800 Date: Tue, 25 Feb 2020 16:42:58 -0800 From: Sean Christopherson To: Jacob Keller Cc: TonyWWang-oc@zhaoxin.com, acme@kernel.org, alexander.shishkin@linux.intel.com, bp@alien8.de, bp@suse.de, hpa@zytor.com, jacob.jun.pan@linux.intel.com, jarkko.sakkinen@linux.intel.com, jmattson@google.com, jolsa@redhat.com, joro@8bytes.org, kvm@vger.kernel.org, lenb@kernel.org, linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-pm@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org, pbonzini@redhat.com, peterz@infradead.org, rkrcmar@redhat.com, shuah@kernel.org, tglx@linutronix.de, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, x86@kernel.org Subject: Re: [PATCH v5 13/19] x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured Message-ID: <20200226004258.GP9245@linux.intel.com> References: <20191221044513.21680-14-sean.j.christopherson@intel.com> <20200225221234.GL9245@linux.intel.com> <1eaf6fbe-0adb-5074-3bc4-1e8327e0cdb3@intel.com> <20200225232900.GO9245@linux.intel.com> <5434303a-0742-3811-fd14-6445d296c0f0@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5434303a-0742-3811-fd14-6445d296c0f0@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-edac-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org On Tue, Feb 25, 2020 at 03:54:34PM -0800, Jacob Keller wrote: > On 2/25/2020 3:29 PM, Sean Christopherson wrote: > > On Tue, Feb 25, 2020 at 02:52:32PM -0800, Jacob Keller wrote: > >> On 2/25/2020 2:12 PM, Sean Christopherson wrote: > >>> On Tue, Feb 25, 2020 at 01:49:13PM -0800, Jacob Keller wrote: > >>>> Hi Sean, > >>>> > >>>> I suspect something is wrong and the features are enabled even though > >>>> the BIOS has it disabled, leading to later failure because of this. > >>> > >>> Hrm. On the failing kernel, what are the values of MSR 0x3a for all CPUs, > >>> i.e. what's the output of 'sudo rdmsr -a 0x3a'? > >>> > >> > >> On the old (fedora 30) kernel, every cpu reports as '1'. > >> > >> I can't easily test the failing kernel because it crashes during boot. > > > > No need, your BIOS is likely locking the MSR, I doubt the value is any > > different when running the new kernel. > > > > Does reverting commit a4d0b2fdbcf7 ("KVM: VMX: Use VMX feature flag to > > query BIOS enabling") resolve the issue? > > > > Is the failing kernel an (umodified) upstream kernel? A stable kernel? > > Or something else? Assuming it's an unmodified upstream kernel, can you > > send your .config? I've tried all the obvious Kconfig combinations but > > haven't been able to reproduce the problem. Staring at the code hasn't > > yielded any revelations either. > > > > I reverted the suggested commit and added some prints: > > [ 26.056398] X86_FEATURE_MSR_IA32_FEAT_CTL is enabled > [ 26.062426] X86_FEATURE_VMX is enabled > [ 26.066923] kvm: disabled by bios > > So the old code flow is finding KVM to be disabled, but both features > are set... > > The code that sets this is run first: > > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_LOCKED is set > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_VMX_ENABLED_INSIDE_SMX is unset > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX is unset > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: MSR locked by bios > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: VMX (outside TXT) disabled by BIOS > > Feb 25 15:46:05 jbrandeb-saw1 kernel: x86/cpu: disabling X86_FEATURE_VMX > > But somehow... it is still set later... > > So there's something weird going on. Maybe "boot_cpu_has" in the > vmx_disabled_by_bios is wrong? Hmm. Hmm, perhaps a bug somewhere else is overwriting the cpufeatures bit for X86_FEATURE_VMX. Let me see if I can reproduce from net-next.