From patchwork Fri Jul 19 16:42:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 11050329 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ACBCB746 for ; Fri, 19 Jul 2019 16:42:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9AD08287AE for ; Fri, 19 Jul 2019 16:42:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8F22828949; Fri, 19 Jul 2019 16:42:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C429287AE for ; Fri, 19 Jul 2019 16:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731292AbfGSQmZ (ORCPT ); Fri, 19 Jul 2019 12:42:25 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:54082 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727577AbfGSQmV (ORCPT ); Fri, 19 Jul 2019 12:42:21 -0400 Received: by mail-wm1-f65.google.com with SMTP id x15so29412192wmj.3; Fri, 19 Jul 2019 09:42:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:subject:date:message-id; bh=SyuzXM1UA0r411S68OsfdkYKutqC9A46TddWlatyHsQ=; b=vTEXtvEHhSuArsy9QXt3XHQbJbvp781op8ZBwDYw39LvNyfC/ICdcmHqY+/BCErSIs 5TgpjeHzeQrXXPycz2Sff3/1oFsCV0fy3a3W6GCrHdqLHR4bYHMCiNUiWYavNGUfxLqM h14Fw/nWo4HtVHTGRy1ElIsU9/AFJBuYcvY69DRa/V0cJP74WDmugxyCOIy9tNfTB6Z0 vr+OPw3OtSdjGN4kpxe532H8GyztrYsC2VOlTosqF05Y8MDMtt9L5ZIozYxhIjjUIUu4 jBe6usBUSBWiQjdCQ4a5WemFS6eJzY6kGs0MDXvoDA7n095RUkuTmNYzDJxjMUsNczxU kBdw== 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:subject:date:message-id; bh=SyuzXM1UA0r411S68OsfdkYKutqC9A46TddWlatyHsQ=; b=nAEEkchpHxOEhNg6HsFdPngjlKQYqxHrWe8WV8b1tRsD/FDuoKTi2l3nTvvw4lX3Vu XyqT5ohyzOy+P9xfE7M3kzyBSM7V/zi10Ot3+zEyhtP/7uU53r1qaD+aglDNfmHg1GBQ tidKXaAgK1HqfzaJsdxruwv6Nb78/f8LuPBSFudVNgZT/wlx8dLdd34AOHH/RoZ0YuS0 JD0mj11uGUEdlw8woHClRTPhlR4BiM+jxobNDqQhJU+Rvp8pAdwRtZbFTrc4Gq/gG3eW B89xgwzFhugUgaQLYARQkuum/v/Wcp667XqNIjFSlBGQ8B3k+EUcR6o2TVrUk3OWHC/y v6fA== X-Gm-Message-State: APjAAAU7OZlwNBodPnSyaBIMR8vBTgHcY7U2iNOAFSGJoAo6HFndyCSP Gb2lDGZi6pwdFNlsIfhbsbpoMK171SY= X-Google-Smtp-Source: APXvYqzWYqZbqCkuugTsLZdVV4wmZfFs6xj6yP8zSZeAXjYDXg/BpLT2hCqiQZgocDM/xwIAKfjpDA== X-Received: by 2002:a7b:c310:: with SMTP id k16mr11083048wmj.133.1563554539165; Fri, 19 Jul 2019 09:42:19 -0700 (PDT) Received: from 640k.localdomain ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id g19sm32764233wmg.10.2019.07.19.09.42.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Jul 2019 09:42:18 -0700 (PDT) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH] KVM: nVMX: do not use dangling shadow VMCS after guest reset Date: Fri, 19 Jul 2019 18:42:14 +0200 Message-Id: <1563554534-46556-3-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 X-Virus-Scanned: ClamAV using ClamSMTP 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 Signed-off-by: Paolo Bonzini Reviewed-by: Liran Alon --- arch/x86/kvm/vmx/nested.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 6e88f459b323..6119b30347c6 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)