From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754268Ab1H2QPM (ORCPT ); Mon, 29 Aug 2011 12:15:12 -0400 Received: from goliath.siemens.de ([192.35.17.28]:18300 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754054Ab1H2QPF (ORCPT ); Mon, 29 Aug 2011 12:15:05 -0400 Message-ID: <4E5BBAEF.8020808@siemens.com> Date: Mon, 29 Aug 2011 18:14:39 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: Jesse Barnes , Brian King , "James E.J. Bottomley" , "Hans J. Koch" , Greg Kroah-Hartman , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "kvm@vger.kernel.org" Subject: Re: Broken pci_block_user_cfg_access interface References: <20110829150552.GA6851@redhat.com> <4E5BB358.3060705@siemens.com> <20110829155835.GB7480@redhat.com> In-Reply-To: <20110829155835.GB7480@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-08-29 17:58, Michael S. Tsirkin wrote: > On Mon, Aug 29, 2011 at 05:42:16PM +0200, Jan Kiszka wrote: >> I still don't get what prevents converting ipr to allow plain mutex >> synchronization. My vision is: >> - push reset-on-error of ipr into workqueue (or threaded IRQ?) >> - require mutex synchronization for common config space access > > Meaning pci_user_ read/write config? And pci_dev_reset, yes. > >> and the >> full reset cycle >> - only exception: INTx status/masking access >> => use pci_lock + test for reset_in_progress, skip operation if >> that is the case >> >> That would allow to drop the whole block_user_cfg infrastructure. >> >> Jan > > We still need to block userspace access while INTx does > the status/masking access, right? Yes, pci_lock would do that for us. We should consider making the related bits for INTx test & mask/unmask generic PCI services so that no user (uio_pci_generic, kvm, vfio) needs to worry about the locking details. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux