From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755075AbZCRIrw (ORCPT ); Wed, 18 Mar 2009 04:47:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753400AbZCRIrm (ORCPT ); Wed, 18 Mar 2009 04:47:42 -0400 Received: from mtagate3.uk.ibm.com ([195.212.29.136]:41484 "EHLO mtagate3.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753371AbZCRIrm (ORCPT ); Wed, 18 Mar 2009 04:47:42 -0400 From: Christian Borntraeger To: Christoph Hellwig Subject: Re: VIRTIO_BLK_T_SCSI_CMD handling in virtio-blk Date: Wed, 18 Mar 2009 09:47:36 +0100 User-Agent: KMail/1.9.9 Cc: Rusty Russell , Anthony Liguori , linux-kernel@vger.kernel.org, hare@suse.de References: <20090318060919.GA21777@infradead.org> In-Reply-To: <20090318060919.GA21777@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200903180947.36878.borntraeger@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Wednesday 18 March 2009 07:09:19 schrieb Christoph Hellwig: > Currently virtio-blk just sends down the payload for packet command > requests, setting the VIRTIO_BLK_T_SCSI_CMD flag in the type field and > zeroing out the sector field. > > But to make any sense of the payload of a packet command we need the > scsi command block (request->cmd) which specifies the operation, > location and length for this command. > > All backends that I checked just fail VIRTIO_BLK_T_SCSI_CMD commands, so > AFAICS no harm is done. But should we really keep this broken support > in the protocol around? If we do want to support packet commands in > the future we should probably just add the command as the first S/G list > entry. Hannes did some implementation for SCSI command passthrough: https://lists.linux-foundation.org/pipermail/virtualization/2008-August/011629.html After some addon fix this was working pretty well. I dont know why Hannes never pushed the final version upstream. Christian