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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C1DB2FA372A for ; Wed, 16 Oct 2019 17:28:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9BA572064B for ; Wed, 16 Oct 2019 17:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388487AbfJPR26 (ORCPT ); Wed, 16 Oct 2019 13:28:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55186 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728901AbfJPR26 (ORCPT ); Wed, 16 Oct 2019 13:28:58 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7652D81F19; Wed, 16 Oct 2019 17:28:58 +0000 (UTC) Received: from x1.home (ovpn-118-102.phx2.redhat.com [10.3.118.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id 26D4F19C4F; Wed, 16 Oct 2019 17:28:58 +0000 (UTC) Date: Wed, 16 Oct 2019 11:28:57 -0600 From: Alex Williamson To: Derek Yerger Cc: kvm@vger.kernel.org, , "Bonzini, Paolo" Subject: Re: PROBLEM: Regression of MMU causing guest VM application errors Message-ID: <20191016112857.293a197d@x1.home> In-Reply-To: <1e525b08-6204-3238-5d56-513f82f1d7fb@djy.llc> References: <1e525b08-6204-3238-5d56-513f82f1d7fb@djy.llc> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 16 Oct 2019 17:28:58 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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, Alex