From patchwork Tue Jun 8 18:28:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 456522 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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 7A78EC47082 for ; Tue, 8 Jun 2021 19:20:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 680D16128E for ; Tue, 8 Jun 2021 19:20:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236136AbhFHTV6 (ORCPT ); Tue, 8 Jun 2021 15:21:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:40970 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235204AbhFHTSF (ORCPT ); Tue, 8 Jun 2021 15:18:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0495F6128E; Tue, 8 Jun 2021 18:51:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623178306; bh=PNZXmBnJwBAjrcJFCMpwg/hNgGTXLtXniNDy/XPXtpA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ujdPluekSRUtAY+bb93VVmORZjYhCxPwPeqx+tu4rZ6b8T8Ao0eJCTg3WnVA+znB+ pxVRUQkAQyVW8Zci7mlKjhH+m6MfJdJijIuQkIuqpV4+jR9MqkHeH/4AxtowxsuxXZ 7uqeer33HVeJ7gqfvL1E/GLdjvyxsYnB+gzXpTo8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Vitaly Kuznetsov , Paolo Bonzini , Andrea Righi , Krzysztof Kozlowski Subject: [PATCH 5.12 152/161] x86/kvm: Disable kvmclock on all CPUs on shutdown Date: Tue, 8 Jun 2021 20:28:02 +0200 Message-Id: <20210608175950.590711549@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210608175945.476074951@linuxfoundation.org> References: <20210608175945.476074951@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vitaly Kuznetsov commit c02027b5742b5aa804ef08a4a9db433295533046 upstream. Currenly, we disable kvmclock from machine_shutdown() hook and this only happens for boot CPU. We need to disable it for all CPUs to guard against memory corruption e.g. on restore from hibernate. Note, writing '0' to kvmclock MSR doesn't clear memory location, it just prevents hypervisor from updating the location so for the short while after write and while CPU is still alive, the clock remains usable and correct so we don't need to switch to some other clocksource. Signed-off-by: Vitaly Kuznetsov Message-Id: <20210414123544.1060604-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini Signed-off-by: Andrea Righi Signed-off-by: Krzysztof Kozlowski Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kvm_para.h | 4 ++-- arch/x86/kernel/kvm.c | 1 + arch/x86/kernel/kvmclock.c | 5 +---- 3 files changed, 4 insertions(+), 6 deletions(-) --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -7,8 +7,6 @@ #include #include -extern void kvmclock_init(void); - #ifdef CONFIG_KVM_GUEST bool kvm_check_and_clear_guest_paused(void); #else @@ -86,6 +84,8 @@ static inline long kvm_hypercall4(unsign } #ifdef CONFIG_KVM_GUEST +void kvmclock_init(void); +void kvmclock_disable(void); bool kvm_para_available(void); unsigned int kvm_arch_para_features(void); unsigned int kvm_arch_para_hints(void); --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -468,6 +468,7 @@ static void kvm_guest_cpu_offline(void) wrmsrl(MSR_KVM_PV_EOI_EN, 0); kvm_pv_disable_apf(); apf_task_wake_all(); + kvmclock_disable(); } static int kvm_cpu_online(unsigned int cpu) --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -220,11 +220,9 @@ static void kvm_crash_shutdown(struct pt } #endif -static void kvm_shutdown(void) +void kvmclock_disable(void) { native_write_msr(msr_kvm_system_time, 0, 0); - kvm_disable_steal_time(); - native_machine_shutdown(); } static void __init kvmclock_init_mem(void) @@ -351,7 +349,6 @@ void __init kvmclock_init(void) #endif x86_platform.save_sched_clock_state = kvm_save_sched_clock_state; x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state; - machine_ops.shutdown = kvm_shutdown; #ifdef CONFIG_KEXEC_CORE machine_ops.crash_shutdown = kvm_crash_shutdown; #endif