From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:36989) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPFmb-0004mt-Iy for qemu-devel@nongnu.org; Wed, 25 May 2011 11:14:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QPFma-00022x-G7 for qemu-devel@nongnu.org; Wed, 25 May 2011 11:14:01 -0400 Received: from mail-ww0-f41.google.com ([74.125.82.41]:57854) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPFhD-0000QI-Oq for qemu-devel@nongnu.org; Wed, 25 May 2011 11:08:27 -0400 Received: by wwi18 with SMTP id 18so3532585wwi.4 for ; Wed, 25 May 2011 08:08:27 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <4DDD1B69.2090100@redhat.com> Date: Wed, 25 May 2011 17:08:25 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1305903817-25476-1-git-send-email-pbonzini@redhat.com> <20110520161436.GA5149@lst.de> <4DD6A6DA.6040808@redhat.com> <20110525131705.GD2283@lst.de> In-Reply-To: <20110525131705.GD2283@lst.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 0/6] SCSI series part 2, rewrite LUN parsing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christoph Hellwig Cc: qemu-devel@nongnu.org On 05/25/2011 03:17 PM, Christoph Hellwig wrote: > On Fri, May 20, 2011 at 07:37:30PM +0200, Paolo Bonzini wrote: >> On 05/20/2011 06:14 PM, Christoph Hellwig wrote: >>> I don't quite understand what you mean with path here. It doesn't >>> seem to map to any SAM concept, nor does it seem to be related >>> to traditional multipathing. >> >> It's what SAM calls a "bus identifier" in the description of LUN addressing >> modes. > > Ok, so it more or less translates to the concept of a "channel" in > the Linux SCSI subsystem. Yes. > It would help if you could explain the concept > in a bit more detail in a comment. Or in fact not bother with it at all, > which should be easy if we never present hierachial LUNs. Unfortunately spapr_vscsi requires hierarchical LUNs. The OpenFirmware code starts by sending out INQUIRY messages to channel 0/1/2/3/4/5/6/7 target 0 LUN 0 (it doesn't recognize other targets or LUNs as far as I can see). So if you want to have a CD-ROM and a HD on your virtual machine, and you want your HD to keep its name both during the installation process and afterwards, you pretty much have to use channel 0 for the HD and another channel for the CD-ROM.. Paolo