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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b2-20020aa79502000000b005cd33628c0fsi583047pfp.177.2023.03.10.13.46.12; Fri, 10 Mar 2023 13:46:27 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=BOROzPRv; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231886AbjCJVnD (ORCPT + 99 others); Fri, 10 Mar 2023 16:43:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231904AbjCJVmr (ORCPT ); Fri, 10 Mar 2023 16:42:47 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16CE8132BDB for ; Fri, 10 Mar 2023 13:42:46 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id bw25-20020a056a00409900b005a9d0e66a7aso3444948pfb.5 for ; Fri, 10 Mar 2023 13:42:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678484565; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=ZTdlaahA+hJ1PbOJKq8XkVSpenQe+RFMEt4am3hb+Bk=; b=BOROzPRv5X6s9tSVq3z98BwKTJA8HOlvQwrcpQkN6WYT7vS2UberlqOHxU6LOf9/No vnPJYo/hIcw84Y+K5/ymxzpbt0gx6purMOlBR2LqSk9NI7rUSgZcDRmCx8zDGlZjeE9H 2qB5i7GsugLTyrrDTn+QrsaKhxR30KMebMJm5Gjz9KQlN1hWLt0uKWdyf+9aFJpQMZa6 KJ+SVMO1L7qsi3MHudN5kpGpyKDTqWIiiXuwIXT7o2rvhSrvIDWZfaJsg46m/A9tCCRm L9mRTradiTVpYVq0IUgcq+EgTnDxAkQzskCQKbLf6sxeM4gQI7gDohUU3Hvvv91ntW6F Mbiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678484565; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ZTdlaahA+hJ1PbOJKq8XkVSpenQe+RFMEt4am3hb+Bk=; b=tnYcWnwJB9gD1OQKSdFQX17+2Qif8cGkmKFI0RAyigxAJYoZpk1Q7sTVKTIp7oxqec 3hwQ9uB/dtRFR97GjDegYJCp387JqQWpiWtUeya8D4JhlKRNhtNIQB67xPah7Jrfy1D4 YKiuLCtyokjThqtvEbcOyWtHUHnkptWw3dGk/t84Z8kT1Vnd/yqri+f0dqG8wRJ899dL A4VkUqFSZrSGS+g/TzvePzfVY82qb7qbtL8cKECQojz/6KkA5SwvP+Fl54aWFMJ4fC/r SOCIcKs7Dt45FWPu23GJ/m86BOQXtrJmUioEBKTgNol75f6e1otbLxqF+mXgfndv66ow 7Pug== X-Gm-Message-State: AO0yUKWTx3YXcJrEJFEnfeK5yljHLNgmrV1NsnUqp65PvaLJG0qwU0Xv 8IWISw49UNq7Ifij4dSPnKojPRqu/XY= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a63:2746:0:b0:503:83e8:9b54 with SMTP id n67-20020a632746000000b0050383e89b54mr1160320pgn.1.1678484565499; Fri, 10 Mar 2023 13:42:45 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 10 Mar 2023 13:42:18 -0800 In-Reply-To: <20230310214232.806108-1-seanjc@google.com> Mime-Version: 1.0 References: <20230310214232.806108-1-seanjc@google.com> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog Message-ID: <20230310214232.806108-5-seanjc@google.com> Subject: [PATCH v2 04/18] x86/reboot: KVM: Handle VMXOFF in KVM's reboot callback From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Sean Christopherson , Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Andrew Cooper , Kai Huang , Chao Gao X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760018864270212312?= X-GMAIL-MSGID: =?utf-8?q?1760018864270212312?= Use KVM VMX's reboot/crash callback to do VMXOFF in an emergency instead of manually and blindly doing VMXOFF. There's no need to attempt VMXOFF if KVM (or some other out-of-tree hypervisor) isn't loaded/active, i.e. if the CPU can't possibly be post-VMXON. Signed-off-by: Sean Christopherson --- arch/x86/include/asm/virtext.h | 10 ---------- arch/x86/kernel/reboot.c | 30 +++++++++--------------------- arch/x86/kvm/vmx/vmx.c | 8 +++++--- 3 files changed, 14 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h index 3b12e6b99412..5bc29fab15da 100644 --- a/arch/x86/include/asm/virtext.h +++ b/arch/x86/include/asm/virtext.h @@ -70,16 +70,6 @@ static inline void __cpu_emergency_vmxoff(void) cpu_vmxoff(); } -/** Disable VMX if it is supported and enabled on the current CPU - */ -static inline void cpu_emergency_vmxoff(void) -{ - if (cpu_has_vmx()) - __cpu_emergency_vmxoff(); -} - - - /* * SVM functions: diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 78182b2969db..5fb1fbf14c82 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -788,13 +788,7 @@ void machine_crash_shutdown(struct pt_regs *regs) #endif #if IS_ENABLED(CONFIG_KVM_INTEL) -/* - * This is used to VMCLEAR all VMCSs loaded on the - * processor. And when loading kvm_intel module, the - * callback function pointer will be assigned. - * - * protected by rcu. - */ +/* RCU-protected callback to disable virtualization prior to reboot. */ static cpu_emergency_virt_cb __rcu *cpu_emergency_virt_callback; void cpu_emergency_register_virt_callback(cpu_emergency_virt_cb *callback) @@ -815,17 +809,6 @@ void cpu_emergency_unregister_virt_callback(cpu_emergency_virt_cb *callback) synchronize_rcu(); } EXPORT_SYMBOL_GPL(cpu_emergency_unregister_virt_callback); - -static inline void cpu_crash_vmclear_loaded_vmcss(void) -{ - cpu_emergency_virt_cb *callback; - - rcu_read_lock(); - callback = rcu_dereference(cpu_emergency_virt_callback); - if (callback) - callback(); - rcu_read_unlock(); -} #endif /* This is the CPU performing the emergency shutdown work. */ @@ -839,10 +822,15 @@ int crashing_cpu = -1; void cpu_emergency_disable_virtualization(void) { #if IS_ENABLED(CONFIG_KVM_INTEL) - cpu_crash_vmclear_loaded_vmcss(); -#endif + cpu_emergency_virt_cb *callback; - cpu_emergency_vmxoff(); + rcu_read_lock(); + callback = rcu_dereference(cpu_emergency_virt_callback); + if (callback) + callback(); + rcu_read_unlock(); +#endif + /* KVM_AMD doesn't yet utilize the common callback. */ cpu_emergency_svm_disable(); } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 41095fc864f3..9e196b9fe183 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -743,7 +743,7 @@ static int vmx_set_guest_uret_msr(struct vcpu_vmx *vmx, return ret; } -static void crash_vmclear_local_loaded_vmcss(void) +static void vmx_emergency_disable(void) { int cpu = raw_smp_processor_id(); struct loaded_vmcs *v; @@ -751,6 +751,8 @@ static void crash_vmclear_local_loaded_vmcss(void) list_for_each_entry(v, &per_cpu(loaded_vmcss_on_cpu, cpu), loaded_vmcss_on_cpu_link) vmcs_clear(v->vmcs); + + __cpu_emergency_vmxoff(); } static void __loaded_vmcs_clear(void *arg) @@ -8551,7 +8553,7 @@ static void __vmx_exit(void) { allow_smaller_maxphyaddr = false; - cpu_emergency_unregister_virt_callback(crash_vmclear_local_loaded_vmcss); + cpu_emergency_unregister_virt_callback(vmx_emergency_disable); vmx_cleanup_l1d_flush(); } @@ -8601,7 +8603,7 @@ static int __init vmx_init(void) pi_init_cpu(cpu); } - cpu_emergency_register_virt_callback(crash_vmclear_local_loaded_vmcss); + cpu_emergency_register_virt_callback(vmx_emergency_disable); vmx_check_vmcs12_offsets();