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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C4768C2BA2B for ; Sat, 11 Apr 2020 16:04:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A424A2083E for ; Sat, 11 Apr 2020 16:04:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726703AbgDKQEX (ORCPT ); Sat, 11 Apr 2020 12:04:23 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:55238 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726070AbgDKQEV (ORCPT ); Sat, 11 Apr 2020 12:04:21 -0400 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jNIc6-0007WY-17; Sat, 11 Apr 2020 18:04:10 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 4414D1C0051; Sat, 11 Apr 2020 18:04:09 +0200 (CEST) Date: Sat, 11 Apr 2020 16:04:08 -0000 From: "tip-bot2 for Xiaoyao Li" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest Cc: Sean Christopherson , Xiaoyao Li , Thomas Gleixner , Borislav Petkov , Paolo Bonzini , x86 , LKML In-Reply-To: <20200410115517.176308876@linutronix.de> References: <20200410115517.176308876@linutronix.de> MIME-Version: 1.0 Message-ID: <158662104885.28353.13755017568373064491.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: e6f8b6c12f03818baacc5f504fe83fa5e20771d6 Gitweb: https://git.kernel.org/tip/e6f8b6c12f03818baacc5f504fe83fa5e20771d6 Author: Xiaoyao Li AuthorDate: Fri, 10 Apr 2020 13:54:02 +02:00 Committer: Borislav Petkov CommitterDate: Sat, 11 Apr 2020 16:42:41 +02:00 KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest Two types of #AC can be generated in Intel CPUs: 1. legacy alignment check #AC 2. split lock #AC Reflect #AC back into the guest if the guest has legacy alignment checks enabled or if split lock detection is disabled. If the #AC is not a legacy one and split lock detection is enabled, then invoke handle_guest_split_lock() which will either warn and disable split lock detection for this task or force SIGBUS on it. [ tglx: Switch it to handle_guest_split_lock() and rename the misnamed helper function. ] Suggested-by: Sean Christopherson Signed-off-by: Xiaoyao Li Signed-off-by: Sean Christopherson Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Acked-by: Paolo Bonzini Link: https://lkml.kernel.org/r/20200410115517.176308876@linutronix.de --- arch/x86/kvm/vmx/vmx.c | 37 ++++++++++++++++++++++++++++++++++--- 1 file changed, 34 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 8959514..8305097 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4588,6 +4588,26 @@ static int handle_machine_check(struct kvm_vcpu *vcpu) return 1; } +/* + * If the host has split lock detection disabled, then #AC is + * unconditionally injected into the guest, which is the pre split lock + * detection behaviour. + * + * If the host has split lock detection enabled then #AC is + * only injected into the guest when: + * - Guest CPL == 3 (user mode) + * - Guest has #AC detection enabled in CR0 + * - Guest EFLAGS has AC bit set + */ +static inline bool guest_inject_ac(struct kvm_vcpu *vcpu) +{ + if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) + return true; + + return vmx_get_cpl(vcpu) == 3 && kvm_read_cr0_bits(vcpu, X86_CR0_AM) && + (kvm_get_rflags(vcpu) & X86_EFLAGS_AC); +} + static int handle_exception_nmi(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -4653,9 +4673,6 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) return handle_rmode_exception(vcpu, ex_no, error_code); switch (ex_no) { - case AC_VECTOR: - kvm_queue_exception_e(vcpu, AC_VECTOR, error_code); - return 1; case DB_VECTOR: dr6 = vmcs_readl(EXIT_QUALIFICATION); if (!(vcpu->guest_debug & @@ -4684,6 +4701,20 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip; kvm_run->debug.arch.exception = ex_no; break; + case AC_VECTOR: + if (guest_inject_ac(vcpu)) { + kvm_queue_exception_e(vcpu, AC_VECTOR, error_code); + return 1; + } + + /* + * Handle split lock. Depending on detection mode this will + * either warn and disable split lock detection for this + * task or force SIGBUS on it. + */ + if (handle_guest_split_lock(kvm_rip_read(vcpu))) + return 1; + fallthrough; default: kvm_run->exit_reason = KVM_EXIT_EXCEPTION; kvm_run->ex.exception = ex_no;