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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 DF626FA372A for ; Wed, 16 Oct 2019 17:49:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C20C12168B for ; Wed, 16 Oct 2019 17:49:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389526AbfJPRtp (ORCPT ); Wed, 16 Oct 2019 13:49:45 -0400 Received: from mga07.intel.com ([134.134.136.100]:18831 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727508AbfJPRto (ORCPT ); Wed, 16 Oct 2019 13:49:44 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Oct 2019 10:49:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,304,1566889200"; d="scan'208";a="186223699" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.41]) by orsmga007.jf.intel.com with ESMTP; 16 Oct 2019 10:49:43 -0700 Date: Wed, 16 Oct 2019 10:49:43 -0700 From: Sean Christopherson To: Alex Williamson Cc: Derek Yerger , kvm@vger.kernel.org, "Bonzini, Paolo" Subject: Re: PROBLEM: Regression of MMU causing guest VM application errors Message-ID: <20191016174943.GG5866@linux.intel.com> References: <1e525b08-6204-3238-5d56-513f82f1d7fb@djy.llc> <20191016112857.293a197d@x1.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191016112857.293a197d@x1.home> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Oct 16, 2019 at 11:28:57AM -0600, Alex Williamson wrote: > On Wed, 16 Oct 2019 00:49:51 -0400 > Derek Yerger wrote: > > > In at least Linux 5.2.7 via Fedora, up to 5.2.18, guest OS applications > > repeatedly crash with segfaults. The problem does not occur on 5.1.16. > > > > System is running Fedora 29 with kernel 5.2.18. Guest OS is Windows 10 with an > > AMD Radeon 540 GPU passthrough. When on 5.2.7 or 5.2.18, specific windows > > applications frequently and repeatedly crash, throwing exceptions in random > > libraries. Going back to 5.1.16, the issue does not occur. > > > > The host system is unaffected by the regression. > > > > Keywords: kvm mmu pci passthrough vfio vfio-pci amdgpu > > > > Possibly related: Unmerged [PATCH] KVM: x86/MMU: Zap all when removing memslot > > if VM has assigned device > > That was never merged because it was superseded by: > > d012a06ab1d2 Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot" > > That revert also induced this commit: > > 002c5f73c508 KVM: x86/mmu: Reintroduce fast invalidate/zap for flushing memslot > > Both of these were merged to stable, showing up in 5.2.11 and 5.2.16 > respectively, so seeing these sorts of issues might be considered a > known issue on 5.2.7, but not 5.2.18 afaik. Do you have a specific > test that reliably reproduces the issue? Thanks, Also, does the failure reproduce on on 5.2.1 - 5.2.6? The memslot debacle exists on all flavors of 5.2.x, if the errors showed up in 5.2.7 then they are being caused by something else.