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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 02D7BC433ED for ; Thu, 20 May 2021 12:59:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCA7B6101D for ; Thu, 20 May 2021 12:59:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243568AbhETNAa (ORCPT ); Thu, 20 May 2021 09:00:30 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37059 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243087AbhETM6B (ORCPT ); Thu, 20 May 2021 08:58:01 -0400 Received: from mail-qt1-f197.google.com ([209.85.160.197]) by youngberry.canonical.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1ljiEA-0005Qt-13 for linux-kernel@vger.kernel.org; Thu, 20 May 2021 12:56:38 +0000 Received: by mail-qt1-f197.google.com with SMTP id o15-20020a05622a138fb02901e0ac29f6b2so12173314qtk.11 for ; Thu, 20 May 2021 05:56:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=/kEoSYvTEjD0iUfvRsRgx66EC2X7g8N60VyX04WfcGw=; b=t+54BjF3KSf3KXXnR1Ivo2fG70Oc6EnAxnhG6vLLHm4oDWAwfquqrFP8Z5neLNyiWv dCdnYgiT+jW5sL9rplxWFC1BfigaNuRp+QdulYOnJTDxh3i7S6i04VoUqNuM39pWWm7q 4lyN+Slv+CH/fNdHTXIqA3mVmQAygWUikiOqURcDM4utbZPbhUgq4yAiNth0aIQR4Ddy RLOcEe77nJ9pwzFZWFCV3qcfsa1bmEtkq86pyBH9H5mvFh2/q/V+yCs2hg/jmHDfB9Z1 ILmzgAWlRzjaNUIQy+VKF+md1HeMAeYd3YHsi6v4vFSDWb4mfdYJcy0S23LMMZNFyc8w z9qQ== X-Gm-Message-State: AOAM530bx+k/A456aR7J81RM9lcuN+CnogJ0HAaJ+WwMye8b90/YGjLa icYCkHmCVM/VZWCOKMfm4jtMqLTvO6Iv74tzjIFvUoLEh6vjWrHO9aJNHaVxakn4hsozPIFTFkQ BgEVnDdwieIsnKer5bmgX4FvLaHY9Bmd7AVD4Edsawg== X-Received: by 2002:a37:ef11:: with SMTP id j17mr3488746qkk.234.1621515397133; Thu, 20 May 2021 05:56:37 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwEiXH6P8bE1nzgR5rYzXvnrvuIULpHjI+O+t+FJYaHyHC3Ojm8/Oua5Gn0lMv6nsTQSrypwg== X-Received: by 2002:a37:ef11:: with SMTP id j17mr3488724qkk.234.1621515396970; Thu, 20 May 2021 05:56:36 -0700 (PDT) Received: from localhost.localdomain ([45.237.48.3]) by smtp.gmail.com with ESMTPSA id g185sm1931471qkf.62.2021.05.20.05.56.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 May 2021 05:56:36 -0700 (PDT) From: Krzysztof Kozlowski To: stable@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Vitaly Kuznetsov , Paolo Bonzini , Andrea Righi , Krzysztof Kozlowski Subject: [PATCH stable v5.4+ 2/3] x86/kvm: Disable kvmclock on all CPUs on shutdown Date: Thu, 20 May 2021 08:56:24 -0400 Message-Id: <20210520125625.12566-2-krzysztof.kozlowski@canonical.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210520125625.12566-1-krzysztof.kozlowski@canonical.com> References: <20210520125625.12566-1-krzysztof.kozlowski@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 --- 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(-) diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 9b4df6eaa11a..a617fd360023 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -6,8 +6,6 @@ #include #include -extern void kvmclock_init(void); - #ifdef CONFIG_KVM_GUEST bool kvm_check_and_clear_guest_paused(void); #else @@ -85,6 +83,8 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1, } #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); diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 6b906a651fb1..f535ba7714f8 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -555,6 +555,7 @@ 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) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 904494b924c1..bd3962953f78 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -214,11 +214,9 @@ static void kvm_crash_shutdown(struct pt_regs *regs) } #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) @@ -346,7 +344,6 @@ 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 -- 2.27.0