From patchwork Thu Nov 28 01:40:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11265117 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1D05B921 for ; Thu, 28 Nov 2019 01:41:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05CA5215F1 for ; Thu, 28 Nov 2019 01:41:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbfK1BlE (ORCPT ); Wed, 27 Nov 2019 20:41:04 -0500 Received: from mga02.intel.com ([134.134.136.20]:10961 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727726AbfK1BkZ (ORCPT ); Wed, 27 Nov 2019 20:40:25 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Nov 2019 17:40:20 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,251,1571727600"; d="scan'208";a="221166509" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by orsmga002.jf.intel.com with ESMTP; 27 Nov 2019 17:40:20 -0800 From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Tony Luck , Tony W Wang-oc , Len Brown , Shuah Khan , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-edac@vger.kernel.org, linux-pm@vger.kernel.org, linux-kselftest@vger.kernel.org, Borislav Petkov , Jarkko Sakkinen Subject: [PATCH v4 14/19] KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR Date: Wed, 27 Nov 2019 17:40:11 -0800 Message-Id: <20191128014016.4389-15-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191128014016.4389-1-sean.j.christopherson@intel.com> References: <20191128014016.4389-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Remove KVM's code to initialize IA32_FEAT_CTL MSR when KVM is loaded now that the MSR is initialized during boot on all CPUs that support VMX, i.e. on all CPUs that can possibly load kvm_intel. Note, don't WARN if IA32_FEAT_CTL is unlocked, even though the MSR is unconditionally locked by init_ia32_feat_ctl(). KVM isn't tied directly to a CPU vendor detection, whereas init_ia32_feat_ctl() is invoked if and only if the CPU vendor is recognized and known to support VMX. As a result, vmx_disabled_by_bios() may be reached without going through init_ia32_feat_ctl() and thus without locking IA32_FEAT_CTL. This quirk will be eliminated in a future patch. Reviewed-by: Jim Mattson Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/vmx.c | 48 +++++++++++++++++------------------------- 1 file changed, 19 insertions(+), 29 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index ecf3ccf71bb2..50dd8026e718 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2207,24 +2207,26 @@ static __init int vmx_disabled_by_bios(void) u64 msr; rdmsrl(MSR_IA32_FEAT_CTL, msr); - if (msr & FEAT_CTL_LOCKED) { - /* launched w/ TXT and VMX disabled */ - if (!(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) - && tboot_enabled()) - return 1; - /* launched w/o TXT and VMX only enabled w/ TXT */ - if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) - && (msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) - && !tboot_enabled()) { - printk(KERN_WARNING "kvm: disable TXT in the BIOS or " - "activate TXT before enabling KVM\n"); - return 1; - } - /* launched w/o TXT and VMX disabled */ - if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) - && !tboot_enabled()) - return 1; + + if (unlikely(!(msr & FEAT_CTL_LOCKED))) + return 1; + + /* launched w/ TXT and VMX disabled */ + if (!(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) && + tboot_enabled()) + return 1; + /* launched w/o TXT and VMX only enabled w/ TXT */ + if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) && + (msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) && + !tboot_enabled()) { + pr_warn("kvm: disable TXT in the BIOS or " + "activate TXT before enabling KVM\n"); + return 1; } + /* launched w/o TXT and VMX disabled */ + if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) && + !tboot_enabled()) + return 1; return 0; } @@ -2241,7 +2243,6 @@ static int hardware_enable(void) { int cpu = raw_smp_processor_id(); u64 phys_addr = __pa(per_cpu(vmxarea, cpu)); - u64 old, test_bits; if (cr4_read_shadow() & X86_CR4_VMXE) return -EBUSY; @@ -2269,17 +2270,6 @@ static int hardware_enable(void) */ crash_enable_local_vmclear(cpu); - rdmsrl(MSR_IA32_FEAT_CTL, old); - - test_bits = FEAT_CTL_LOCKED; - test_bits |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX; - if (tboot_enabled()) - test_bits |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX; - - if ((old & test_bits) != test_bits) { - /* enable and lock */ - wrmsrl(MSR_IA32_FEAT_CTL, old | test_bits); - } kvm_cpu_vmxon(phys_addr); if (enable_ept) ept_sync_global();