From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] virtio-blk: add SGI_IO passthru support Date: Mon, 27 Apr 2009 09:36:51 -0500 Message-ID: <49F5C303.3060003@codemonkey.ws> References: <20090427082606.GA32604@lst.de> <20090427082914.GA383@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, Rusty Russell , Hannes Reinecke , Christian Borntraeger , kvm@vger.kernel.org To: Christoph Hellwig Return-path: Received: from yw-out-2324.google.com ([74.125.46.29]:35178 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751688AbZD0Og4 (ORCPT ); Mon, 27 Apr 2009 10:36:56 -0400 Received: by yw-out-2324.google.com with SMTP id 5so1384462ywb.1 for ; Mon, 27 Apr 2009 07:36:55 -0700 (PDT) In-Reply-To: <20090427082914.GA383@lst.de> Sender: kvm-owner@vger.kernel.org List-ID: Christoph Hellwig wrote: > [had the qemu list address wrong the first time, reply to this message, > not the previous if you were on Cc] > > > Add support for SG_IO passthru (packet commands) to the virtio-blk > backend. Conceptually based on an older patch from Hannes Reinecke > but largely rewritten to match the code structure and layering in > virtio-blk. > > Note that currently we issue the hose SG_IO synchronously. We could > easily switch to async I/O, but that would required either bloating > the VirtIOBlockReq by the size of struct sg_io_hdr or an additional > memory allocation for each SG_IO request. > > > Signed-off-by: Christoph Hellwig > So practically speaking, what can you do with this? Should we be handling some SCSI cmds internally to QEMU (like eject operations) and supporting media=cdrom in -drive for if=virtio? On a related topic, should we switch /dev/vdX to be /dev/sdX? Regards, Anthony Liguori