From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752702Ab0FWOFm (ORCPT ); Wed, 23 Jun 2010 10:05:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58404 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751367Ab0FWOFk (ORCPT ); Wed, 23 Jun 2010 10:05:40 -0400 Date: Wed, 23 Jun 2010 16:59:47 +0300 From: "Michael S. Tsirkin" To: Avi Kivity Cc: virtualization@lists.linux-foundation.org, Anthony Liguori , linux-pci@vger.kernel.org, Matt Carlson , linux-kernel@vger.kernel.org, Jesse Barnes , "Rafael J. Wysocki" , Kenji Kaneshige , Tejun Heo , "David S. Miller" , Bjorn Helgaas Subject: Re: [PATCH for-2.6.35] virtio-pci: disable msi at startup Message-ID: <20100623135946.GA30526@redhat.com> References: <20100610152252.GA3510@redhat.com> <4C22132F.4060307@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C22132F.4060307@redhat.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 23, 2010 at 04:59:11PM +0300, Avi Kivity wrote: > On 06/10/2010 06:22 PM, Michael S. Tsirkin wrote: >> virtio-pci resets the device at startup by writing to the status >> register, but this does not clear the pci config space, >> specifically msi enable status which affects register >> layout. >> >> This breaks things like kdump when they try to use e.g. virtio-blk. >> >> Fix by forcing msi off at startup. Since pci.c already has >> a routine to do this, we export and use it instead of duplicating code. >> >> > > Why doesn't a device reset result in msi being cleared? This is not a standard function reset. This is virtio specific command. So it only clears virtio registers. > Shouldn't a reset be equivalent to power cycling? If we did this, driver would need to restore registers such as BAR etc. > -- > error compiling committee.c: too many arguments to function