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=-9.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 7D785C76195 for ; Fri, 19 Jul 2019 21:39:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5567521880 for ; Fri, 19 Jul 2019 21:39:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="J5/uLkUQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388354AbfGSVjz (ORCPT ); Fri, 19 Jul 2019 17:39:55 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:36534 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727528AbfGSVjz (ORCPT ); Fri, 19 Jul 2019 17:39:55 -0400 Received: by mail-wm1-f66.google.com with SMTP id g67so26127378wme.1; Fri, 19 Jul 2019 14:39:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=dJZwB/Clkci6ZFRbtdSU37FYwxEFZIATbsU+Tyu15yU=; b=J5/uLkUQiySkxXmK4m2T0AjaKrFTGYUOyNeGEK/FehRSVzgscPlWhQi3qkQ1LU7R1H t/fN2q9m/LRjIgu59k+dJllD0xfhaHaoHFBXemQbpAfD6UphBhYJeJ03Uv8+E7ckRFc4 YPCJGeORBPmXuqlD2Ir10H8NA/XeZTzr3uKGVO2nGUSUAs3LfeK9aU8qZH5fkZu6Oqd3 LBk0KI38nPeuqE6fM/aASkK8CDDk0ze/P/OjZmPt4nIvoyt+YmyBnaFTuoWC+PCMMMM3 Lur/5TnAZCngt3K7UlBO5OQZEakO+WOpSopYTjpRGZgAZGFQVRDbLCGCJSAwIQjGmi7z MOiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id; bh=dJZwB/Clkci6ZFRbtdSU37FYwxEFZIATbsU+Tyu15yU=; b=i91lo4GOHzSZl7lsAyfsuZ1dbJJXj1o++1IoC3JkgV7RPCAkrjm/WSmzypiMudS/u8 i7xKxRGf9kzFZU/ht5q+/GfOnCV/ExVv0NRCREqLbxY1hJ3MUEZSSBZY6PXw2rAnTBvm 8gYfTKqeio/MuN0ZFgo4eDokXwDQRblIv5yDx36P/CtO8y/N4RSbt14k7/Amk36vweH4 nCRdDgiE5dqeMBW4956K0nB6t7uI6z6d8Wyod59MMTSKOt+sd7vH0GgNt4fAK8n236Jl K3ULj6niZBK3dxWLhxhwuM0bwd36mRXF1kxCIHlxY0oM3otbolBSLOpuas/ZqTBedFHc IEYw== X-Gm-Message-State: APjAAAWaXHqbM32MrbFQ5tPOeHSKox29AnH8m4QKic2V/HYnGm5GfbPS t6dKa3VZeznlXYF2HsC8aXNuvBoQ9aA= X-Google-Smtp-Source: APXvYqy22DLKRAzSsbKsRzshsG+BNywMNiZsLK/xOpZhQVmuyq2WCMJhopvjLFhb8SHCCAhir6F9eA== X-Received: by 2002:a05:600c:da:: with SMTP id u26mr48223115wmm.108.1563572392538; Fri, 19 Jul 2019 14:39:52 -0700 (PDT) Received: from 640k.localdomain ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id i18sm39303874wrp.91.2019.07.19.14.39.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Jul 2019 14:39:51 -0700 (PDT) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Liran Alon , stable@vger.kernel.org Subject: [PATCH v2] KVM: nVMX: do not use dangling shadow VMCS after guest reset Date: Fri, 19 Jul 2019 23:39:50 +0200 Message-Id: <1563572390-28823-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org If a KVM guest is reset while running a nested guest, free_nested will disable the shadow VMCS execution control in the vmcs01. However, on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync the VMCS12 to the shadow VMCS which has since been freed. This causes a vmptrld of a NULL pointer on my machime, but Jan reports the host to hang altogether. Let's see how much this trivial patch fixes. Reported-by: Jan Kiszka Cc: Liran Alon Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 4f23e34f628b..0f1378789bd0 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -194,6 +194,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx) { secondary_exec_controls_clearbit(vmx, SECONDARY_EXEC_SHADOW_VMCS); vmcs_write64(VMCS_LINK_POINTER, -1ull); + vmx->nested.need_vmcs12_to_shadow_sync = false; } static inline void nested_release_evmcs(struct kvm_vcpu *vcpu) @@ -1341,6 +1342,9 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) unsigned long val; int i; + if (WARN_ON(!shadow_vmcs)) + return; + preempt_disable(); vmcs_load(shadow_vmcs); @@ -1373,6 +1377,9 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) unsigned long val; int i, q; + if (WARN_ON(!shadow_vmcs)) + return; + vmcs_load(shadow_vmcs); for (q = 0; q < ARRAY_SIZE(fields); q++) { @@ -4436,7 +4443,6 @@ static inline void nested_release_vmcs12(struct kvm_vcpu *vcpu) /* copy to memory all shadowed fields in case they were modified */ copy_shadow_to_vmcs12(vmx); - vmx->nested.need_vmcs12_to_shadow_sync = false; vmx_disable_shadow_vmcs(vmx); } vmx->nested.posted_intr_nv = -1; -- 1.8.3.1