From patchwork Wed Apr 22 09:55:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 227045 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, 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 7FCD2C55189 for ; Wed, 22 Apr 2020 10:58:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C35A2076E for ; Wed, 22 Apr 2020 10:58:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587553087; bh=1ikYEs3EOoE+TbYWpEa/q2UTB0sAEjEFWOcDFUvzuAE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pr7mN4sZiLi/d8LNi5BAvKUe29gM1k281cMgz7bdUofdfUhue4g5ssoNu2m7GW6wW BC0RsA8eeQQKb5pNsRGkbrx98pLbs1OHSyyhr1zRjg4O/HMUc8ofoKhirR7hDba2HG SvoZ0oKRfed9rrRY9UiNJu9YNXlIhPa0IIqivor4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728007AbgDVKEc (ORCPT ); Wed, 22 Apr 2020 06:04:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:54958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728032AbgDVKEc (ORCPT ); Wed, 22 Apr 2020 06:04:32 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0F77120575; Wed, 22 Apr 2020 10:04:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587549870; bh=1ikYEs3EOoE+TbYWpEa/q2UTB0sAEjEFWOcDFUvzuAE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j9FhSkIO+X+PpBacDBKOoFJIlLY8nJ/ASeeoldIo5ee/rFtcVBGZ/+SssgQ8Uvuw1 hC+VdNa91pABPYdTNjG6W2EYn5BaKHOHaEWdEcqfeZqKOD5wF/zBXMAqxzFn+79YBK B7j7GW4Vbt4BXKjcYsLIDzyW+psI3kXbJ2KhOfQM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Sean Christopherson , Paolo Bonzini Subject: [PATCH 4.9 039/125] KVM: VMX: fix crash cleanup when KVM wasnt used Date: Wed, 22 Apr 2020 11:55:56 +0200 Message-Id: <20200422095039.813059238@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095032.909124119@linuxfoundation.org> References: <20200422095032.909124119@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vitaly Kuznetsov commit dbef2808af6c594922fe32833b30f55f35e9da6d upstream. If KVM wasn't used at all before we crash the cleanup procedure fails with BUG: unable to handle page fault for address: ffffffffffffffc8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 23215067 P4D 23215067 PUD 23217067 PMD 0 Oops: 0000 [#8] SMP PTI CPU: 0 PID: 3542 Comm: bash Kdump: loaded Tainted: G D 5.6.0-rc2+ #823 RIP: 0010:crash_vmclear_local_loaded_vmcss.cold+0x19/0x51 [kvm_intel] The root cause is that loaded_vmcss_on_cpu list is not yet initialized, we initialize it in hardware_enable() but this only happens when we start a VM. Previously, we used to have a bitmap with enabled CPUs and that was preventing [masking] the issue. Initialized loaded_vmcss_on_cpu list earlier, right before we assign crash_vmclear_loaded_vmcss pointer. blocked_vcpu_on_cpu list and blocked_vcpu_on_cpu_lock are moved altogether for consistency. Fixes: 31603d4fc2bb ("KVM: VMX: Always VMCLEAR in-use VMCSes during crash with kexec support") Signed-off-by: Vitaly Kuznetsov Message-Id: <20200401081348.1345307-1-vkuznets@redhat.com> Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3482,10 +3482,6 @@ static int hardware_enable(void) if (cr4_read_shadow() & X86_CR4_VMXE) return -EBUSY; - INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); - INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu)); - spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); - rdmsrl(MSR_IA32_FEATURE_CONTROL, old); test_bits = FEATURE_CONTROL_LOCKED; @@ -11860,7 +11856,7 @@ module_exit(vmx_exit) static int __init vmx_init(void) { - int r; + int r, cpu; r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), __alignof__(struct vcpu_vmx), THIS_MODULE); @@ -11882,6 +11878,12 @@ static int __init vmx_init(void) } } + for_each_possible_cpu(cpu) { + INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); + INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu)); + spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + } + #ifdef CONFIG_KEXEC_CORE rcu_assign_pointer(crash_vmclear_loaded_vmcss, crash_vmclear_local_loaded_vmcss);