From patchwork Sat Feb 1 18:51:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11361351 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 C2CE9139A for ; Sat, 1 Feb 2020 18:57:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A876520679 for ; Sat, 1 Feb 2020 18:57:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727754AbgBAS5I (ORCPT ); Sat, 1 Feb 2020 13:57:08 -0500 Received: from mga01.intel.com ([192.55.52.88]:57278 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726893AbgBASw1 (ORCPT ); Sat, 1 Feb 2020 13:52:27 -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 fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Feb 2020 10:52:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,390,1574150400"; d="scan'208";a="248075446" 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 06/61] KVM: x86: Move CPUID 0xD.1 handling out of the index>0 loop Date: Sat, 1 Feb 2020 10:51:23 -0800 Message-Id: <20200201185218.24473-7-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 Mov the sub-leaf 1 handling for CPUID 0xD out of the index>0 loop so that the loop only handles index>2. Sub-leafs 2+ have identical semantics, whereas sub-leaf 1 is effectively a feature sub-leaf. Moving sub-leaf 1 out of the loop does duplicate a bit of code, but the nent/maxnent code will be consolidated in a future patch, and duplicating the clear of ECX/EDX is arguably a good thing as the reasons for clearing said registers are completely different. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Vitaly Kuznetsov --- arch/x86/kvm/cpuid.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index e5cf1e0cf84a..fc8540596386 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -653,26 +653,33 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, if (!supported) break; - for (idx = 1, i = 1; idx < 64; ++idx) { + if (*nent >= maxnent) + goto out; + + do_host_cpuid(&entry[1], function, 1); + ++*nent; + + entry[1].eax &= kvm_cpuid_D_1_eax_x86_features; + cpuid_mask(&entry[1].eax, CPUID_D_1_EAX); + if (entry[1].eax & (F(XSAVES)|F(XSAVEC))) + entry[1].ebx = xstate_required_size(supported, true); + else + entry[1].ebx = 0; + /* Saving XSS controlled state via XSAVES isn't supported. */ + entry[1].ecx = 0; + entry[1].edx = 0; + + for (idx = 2, i = 2; idx < 64; ++idx) { u64 mask = ((u64)1 << idx); + if (*nent >= maxnent) goto out; do_host_cpuid(&entry[i], function, idx); - if (idx == 1) { - entry[i].eax &= kvm_cpuid_D_1_eax_x86_features; - cpuid_mask(&entry[i].eax, CPUID_D_1_EAX); - entry[i].ebx = 0; - if (entry[i].eax & (F(XSAVES)|F(XSAVEC))) - entry[i].ebx = - xstate_required_size(supported, - true); - } else { - if (entry[i].eax == 0 || !(supported & mask)) - continue; - if (WARN_ON_ONCE(entry[i].ecx & 1)) - continue; - } + if (entry[i].eax == 0 || !(supported & mask)) + continue; + if (WARN_ON_ONCE(entry[i].ecx & 1)) + continue; entry[i].ecx = 0; entry[i].edx = 0; ++*nent;