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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 328A4C33CB7 for ; Sat, 1 Feb 2020 18:52:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14F0120661 for ; Sat, 1 Feb 2020 18:52:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727074AbgBASw2 (ORCPT ); Sat, 1 Feb 2020 13:52:28 -0500 Received: from mga05.intel.com ([192.55.52.43]:37509 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726354AbgBASw1 (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 fmsmga105.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="248075449" 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 07/61] KVM: x86: Check for CPUID 0xD.N support before validating array size Date: Sat, 1 Feb 2020 10:51:24 -0800 Message-Id: <20200201185218.24473-8-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 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that sub-leaf 1 is handled separately, verify the next sub-leaf is needed before rejecting KVM_GET_SUPPORTED_CPUID due to an insufficiently sized userspace array. Note, although this is technically a bug, it's not visible to userspace as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE, which is hardcoded to be added after leaf 0xD. The real motivation for the change is to tightly couple the nent/maxnent and do_host_cpuid() sequences in preparation for future cleanup. Signed-off-by: Sean Christopherson --- arch/x86/kvm/cpuid.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index fc8540596386..fd9b29aa7abc 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -670,13 +670,14 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, entry[1].edx = 0; for (idx = 2, i = 2; idx < 64; ++idx) { - u64 mask = ((u64)1 << idx); + if (!(supported & BIT_ULL(idx))) + continue; if (*nent >= maxnent) goto out; do_host_cpuid(&entry[i], function, idx); - if (entry[i].eax == 0 || !(supported & mask)) + if (entry[i].eax == 0) continue; if (WARN_ON_ONCE(entry[i].ecx & 1)) continue; -- 2.24.1