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 2CC8DC4BA06 for ; Tue, 25 Feb 2020 23:54:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C7222075D for ; Tue, 25 Feb 2020 23:54:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729683AbgBYXyh (ORCPT ); Tue, 25 Feb 2020 18:54:37 -0500 Received: from mga06.intel.com ([134.134.136.31]:56759 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729090AbgBYXyh (ORCPT ); Tue, 25 Feb 2020 18:54:37 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Feb 2020 15:54:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,486,1574150400"; d="scan'208";a="230279712" Received: from jekeller-mobl1.amr.corp.intel.com (HELO [134.134.177.78]) ([134.134.177.78]) by fmsmga007.fm.intel.com with ESMTP; 25 Feb 2020 15:54:34 -0800 Subject: Re: [PATCH v5 13/19] x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured To: Sean Christopherson 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 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> From: Jacob Keller Organization: Intel Corporation Message-ID: <5434303a-0742-3811-fd14-6445d296c0f0@intel.com> Date: Tue, 25 Feb 2020 15:54:34 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200225232900.GO9245@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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.