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=-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 4DB04C352BE for ; Thu, 16 Apr 2020 13:34:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D42320732 for ; Thu, 16 Apr 2020 13:34:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044092; bh=jU2NGxoZVfqGEeV789O2fBDa8eNmaSTF3BTMq0ydWxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xFc+DP+GKF08kNEop+0hb0oHMxMoR7qTdAV6EUjXceOFp3/+ZGVAYZovMVdTZbEbB fAYXTs0b0OJKmWZjidxuBNVcEtx5ekqLauNaXqx2IGiw98FFclCdU/BlSOBWXnrDfW foSBOCu3XKAtI92yq6qNa/qLjaX9yLGhRl8MKIGo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2896414AbgDPNes (ORCPT ); Thu, 16 Apr 2020 09:34:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:38740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2895952AbgDPN3J (ORCPT ); Thu, 16 Apr 2020 09:29:09 -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 BB40721D79; Thu, 16 Apr 2020 13:29:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587043749; bh=jU2NGxoZVfqGEeV789O2fBDa8eNmaSTF3BTMq0ydWxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bvYc46qRBpPM+/I2TOvC5FDWN57abOAyWvlKLP7W2zeZDijjzRoYmCR/d/NA0TYI4 LNeuNuUIIsQsjzk429YwkCBRvtM+vKkqYyoLTAYourgc4BdP0DBBIWfqfYrBuCSh4f EjbQe+Hz5Gkheyp7bhFgY60iRkFYX1xjNGawcaPo= 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 4.19 085/146] KVM: VMX: fix crash cleanup when KVM wasnt used Date: Thu, 16 Apr 2020 15:23:46 +0200 Message-Id: <20200416131254.426476528@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131242.353444678@linuxfoundation.org> References: <20200416131242.353444678@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -4398,10 +4398,6 @@ static int hardware_enable(void) !hv_get_vp_assist_page(cpu)) return -EFAULT; - 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; @@ -14554,7 +14550,7 @@ module_exit(vmx_exit); static int __init vmx_init(void) { - int r; + int r, cpu; #if IS_ENABLED(CONFIG_HYPERV) /* @@ -14605,6 +14601,12 @@ 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);