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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 29303C3F2D1 for ; Tue, 3 Mar 2020 00:02:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F26B524680 for ; Tue, 3 Mar 2020 00:02:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727228AbgCCAB7 (ORCPT ); Mon, 2 Mar 2020 19:01:59 -0500 Received: from mga17.intel.com ([192.55.52.151]:37735 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727143AbgCBX5Z (ORCPT ); Mon, 2 Mar 2020 18:57:25 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2020 15:57:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,509,1574150400"; d="scan'208";a="243384761" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga006.jf.intel.com with ESMTP; 02 Mar 2020 15:57:23 -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, Xiaoyao Li Subject: [PATCH v2 46/66] KVM: x86: Remove the unnecessary loop on CPUID 0x7 sub-leafs Date: Mon, 2 Mar 2020 15:56:49 -0800 Message-Id: <20200302235709.27467-47-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200302235709.27467-1-sean.j.christopherson@intel.com> References: <20200302235709.27467-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Explicitly handle CPUID 0x7 sub-leaf 1. The kernel is currently aware of exactly one feature in CPUID 0x7.1, which means there is room for another 127 features before CPUID 0x7.2 will see the light of day, i.e. the looping is likely to be dead code for years to come. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Sean Christopherson --- arch/x86/kvm/cpuid.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index e3e5a7b83b5b..617b532e51a1 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -541,11 +541,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) if (boot_cpu_has(X86_FEATURE_AMD_SSBD)) cpuid_entry_set(entry, X86_FEATURE_SPEC_CTRL_SSBD); - for (i = 1, max_idx = entry->eax; i <= max_idx; i++) { - if (WARN_ON_ONCE(i > 1)) - break; - - entry = do_host_cpuid(array, function, i); + /* KVM only supports 0x7.0 and 0x7.1, capped above via min(). */ + if (entry->eax == 1) { + entry = do_host_cpuid(array, function, 1); if (!entry) goto out; -- 2.24.1