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=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 1E463C3F2CE for ; Thu, 5 Mar 2020 01:35:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F29C221741 for ; Thu, 5 Mar 2020 01:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726436AbgCEBeq (ORCPT ); Wed, 4 Mar 2020 20:34:46 -0500 Received: from mga03.intel.com ([134.134.136.65]:31873 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725776AbgCEBek (ORCPT ); Wed, 4 Mar 2020 20:34:40 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Mar 2020 17:34:39 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,516,1574150400"; d="scan'208";a="234301747" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by fmsmga008.fm.intel.com with ESMTP; 04 Mar 2020 17:34:39 -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, Pu Wen Subject: [PATCH v2 2/7] KVM: x86: Add helpers to perform CPUID-based guest vendor check Date: Wed, 4 Mar 2020 17:34:32 -0800 Message-Id: <20200305013437.8578-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200305013437.8578-1-sean.j.christopherson@intel.com> References: <20200305013437.8578-1-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 Add helpers to provide CPUID-based guest vendor checks, i.e. to do the ugly register comparisons. Use the new helpers to check for an AMD guest vendor in guest_cpuid_is_amd() as well as in the existing emulator flows. Using the new helpers fixes a _very_ theoretical bug where guest_cpuid_is_amd() would get a false positive on a non-AMD virtual CPU with a vendor string beginning with "Auth" due to the previous logic only checking EBX. It also fixes a marginally less theoretically bug where guest_cpuid_is_amd() would incorrectly return false for a guest CPU with "AMDisbetter!" as its vendor string. Fixes: a0c0feb57992c ("KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD") Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_emulate.h | 24 ++++++++++++++++++++ arch/x86/kvm/cpuid.h | 2 +- arch/x86/kvm/emulate.c | 36 +++++++----------------------- 3 files changed, 33 insertions(+), 29 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index bf5f5e476f65..2754972c36e6 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -393,6 +393,30 @@ struct x86_emulate_ctxt { #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69 +static inline bool is_guest_vendor_intel(u32 ebx, u32 ecx, u32 edx) +{ + return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx && + ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx && + edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx; +} + +static inline bool is_guest_vendor_amd(u32 ebx, u32 ecx, u32 edx) +{ + return (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx && + ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx && + edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) || + (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx && + ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx && + edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx); +} + +static inline bool is_guest_vendor_hygon(u32 ebx, u32 ecx, u32 edx) +{ + return ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx && + ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx && + edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx; +} + enum x86_intercept_stage { X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */ X86_ICPT_PRE_EXCEPT, diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index 7366c618aa04..13eb3e92c6a9 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -145,7 +145,7 @@ static inline bool guest_cpuid_is_amd(struct kvm_vcpu *vcpu) struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, 0, 0); - return best && best->ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx; + return best && is_guest_vendor_amd(best->ebx, best->ecx, best->edx); } static inline int guest_cpuid_family(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index dd19fb3539e0..9cf303984fe5 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2712,9 +2712,7 @@ static bool vendor_intel(struct x86_emulate_ctxt *ctxt) eax = ecx = 0; ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); - return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx - && ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx - && edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx; + return is_guest_vendor_intel(ebx, ecx, edx); } static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) @@ -2733,34 +2731,16 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) ecx = 0x00000000; ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); /* - * Intel ("GenuineIntel") - * remark: Intel CPUs only support "syscall" in 64bit - * longmode. Also an 64bit guest with a - * 32bit compat-app running will #UD !! While this - * behaviour can be fixed (by emulating) into AMD - * response - CPUs of AMD can't behave like Intel. + * remark: Intel CPUs only support "syscall" in 64bit longmode. Also a + * 64bit guest with a 32bit compat-app running will #UD !! While this + * behaviour can be fixed (by emulating) into AMD response - CPUs of + * AMD can't behave like Intel. */ - if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx && - ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx && - edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx) + if (is_guest_vendor_intel(ebx, ecx, edx)) return false; - /* AMD ("AuthenticAMD") */ - if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx && - ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx && - edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) - return true; - - /* AMD ("AMDisbetter!") */ - if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx && - ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx && - edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx) - return true; - - /* Hygon ("HygonGenuine") */ - if (ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx && - ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx && - edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx) + if (is_guest_vendor_amd(ebx, ecx, edx) || + is_guest_vendor_hygon(ebx, ecx, edx)) return true; /* -- 2.24.1