From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:56833) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPEyy-0005Oe-3S for qemu-devel@nongnu.org; Wed, 25 May 2011 10:22:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QPEyx-0003FK-42 for qemu-devel@nongnu.org; Wed, 25 May 2011 10:22:43 -0400 Received: from verein.lst.de ([213.95.11.211]:36519 helo=newverein.lst.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPEyw-0003EO-Tj for qemu-devel@nongnu.org; Wed, 25 May 2011 10:22:43 -0400 Date: Wed, 25 May 2011 15:05:01 +0200 From: Christoph Hellwig Message-ID: <20110525130501.GA2283@lst.de> References: <1305903817-25476-1-git-send-email-pbonzini@redhat.com> <1305903817-25476-3-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1305903817-25476-3-git-send-email-pbonzini@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH 2/6] scsi: support parsing of SAM logical unit numbers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, David Gibson On Fri, May 20, 2011 at 05:03:33PM +0200, Paolo Bonzini wrote: > SAM logical unit numbers are complicated beasts that can address > multiple levels of buses and targets before finally reaching > logical units. Begin supporting them by correctly parsing vSCSI > LUNs. > > Note that with the current (admittedly incorrect) code OpenFirmware > thought the devices were at "bus X, target 0, lun 0" (because OF > prefers access mode 0, which places bus numbers in the top byte), > while Linux thought it was "bus 0, target Y, lun 0" (because Linux > uses access mode 2, which places target numbers in the top byte). > With this patch, everything consistently uses the former notation. Do we actually need the complete LUN encoding scheme? What speaks against always presenting the flat LUN addressing scheme to guests?