From patchwork Sat Feb 1 18:51:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11361331 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 0D4F0159A for ; Sat, 1 Feb 2020 18:56:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E85A4206F0 for ; Sat, 1 Feb 2020 18:56:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727546AbgBAS4c (ORCPT ); Sat, 1 Feb 2020 13:56:32 -0500 Received: from mga05.intel.com ([192.55.52.43]:37515 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726976AbgBASw2 (ORCPT ); Sat, 1 Feb 2020 13:52:28 -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 fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Feb 2020 10:52:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,390,1574150400"; d="scan'208";a="248075465" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga002.jf.intel.com with ESMTP; 01 Feb 2020 10:52:25 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 12/61] KVM: x86: Drop redundant boot cpu checks on SSBD feature bits Date: Sat, 1 Feb 2020 10:51:29 -0800 Message-Id: <20200201185218.24473-13-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200201185218.24473-1-sean.j.christopherson@intel.com> References: <20200201185218.24473-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Drop redundnant checks when "emulating" SSBD feature across vendors, i.e. advertising the AMD variant when running on an Intel CPU and vice versa. Both SPEC_CTRL_SSBD and AMD_SSBD are already defined in the leaf-specific feature masks and are *not* forcefully set by the kernel, i.e. will already be set in the entry when supported by the host. Functionally, this changes nothing, but the redundant check is confusing, especially when considering future patches that will further differentiate between "real" and "emulated" feature bits. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/kvm/cpuid.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index fd04f17d1836..52f0af4e10d5 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -405,8 +405,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry) entry->edx |= F(SPEC_CTRL); if (boot_cpu_has(X86_FEATURE_STIBP)) entry->edx |= F(INTEL_STIBP); - if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) || - boot_cpu_has(X86_FEATURE_AMD_SSBD)) + if (boot_cpu_has(X86_FEATURE_AMD_SSBD)) entry->edx |= F(SPEC_CTRL_SSBD); /* * We emulate ARCH_CAPABILITIES in software even @@ -780,8 +779,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, entry->ebx |= F(AMD_IBRS); if (boot_cpu_has(X86_FEATURE_STIBP)) entry->ebx |= F(AMD_STIBP); - if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) || - boot_cpu_has(X86_FEATURE_AMD_SSBD)) + if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) entry->ebx |= F(AMD_SSBD); if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS)) entry->ebx |= F(AMD_SSB_NO);