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=-1.0 required=3.0 tests=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 33BEAC3F2C6 for ; Thu, 27 Feb 2020 23:01:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2FE424695 for ; Thu, 27 Feb 2020 23:01:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729733AbgB0XBJ convert rfc822-to-8bit (ORCPT ); Thu, 27 Feb 2020 18:01:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:54068 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726845AbgB0XBI (ORCPT ); Thu, 27 Feb 2020 18:01:08 -0500 From: bugzilla-daemon@bugzilla.kernel.org To: kvm@vger.kernel.org Subject: [Bug 206579] KVM with passthrough generates "BUG: kernel NULL pointer dereference" and crashes Date: Thu, 27 Feb 2020 23:00:46 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Product: Virtualization X-Bugzilla-Component: kvm X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: anthonysanwo@googlemail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc attachments.created Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=206579 Anthony (anthonysanwo@googlemail.com) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |anthonysanwo@googlemail.com --- Comment #28 from Anthony (anthonysanwo@googlemail.com) --- Created attachment 287685 --> https://bugzilla.kernel.org/attachment.cgi?id=287685&action=edit avic_inhibit_reasons-anthony Hi I also just wanted to give my observations I have found when testing the patches. I confirm I also don't have don't have crashes relating to the original report. I have been trying out the SVM AVIC patches since around the first patch that was submitted but never got round to documentation my testing until recently. I can't remember the specific patch set/kernel version I tried but I remember having avic apparently working with when synic + stimer where enabled but not without. If my understanding is correctly this shouldn't be the case as synic is meant to be a case when avic is permanently disabled. This is still the case with current patchset. In summary I can get avic reporting it's working according to perf stat and trace logs when synic is on but not working when synic is off. Using EPYC-IBPB or passthrough doesn't change the avic_inhibit_reasons. With Synic I get avic_inhibit_reasons - 10 With Synic+Stimer off I get - 0 To note I am using arch linux + qemu 4.2 + linux-mainline-5.6.0-rc2. Please see a small trace log of synic on vs off, domain capabilities, perf stat and patches used. These were recording once the VM was launched and sitting at the login screen. Please let me know if there is any other info I get provide to help. -- You are receiving this mail because: You are watching the assignee of the bug.