From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [Qemu-devel] [PATCH][v7] megasas: LSI Megaraid SAS emulation Date: Wed, 20 Jul 2011 08:50:40 +0200 Message-ID: <4E267AC0.7060307@suse.de> References: <1311074364-3489-1-git-send-email-hare@suse.de> <20110719160843.GA3414@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: qemu-devel@nongnu.org, Paolo Bonzini , Stefan Haynoczi , kvm@vger.kernel.org, Alexander Graf To: Christoph Hellwig Return-path: Received: from cantor2.suse.de ([195.135.220.15]:34970 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769Ab1GTGuo (ORCPT ); Wed, 20 Jul 2011 02:50:44 -0400 In-Reply-To: <20110719160843.GA3414@lst.de> Sender: kvm-owner@vger.kernel.org List-ID: On 07/19/2011 06:08 PM, Christoph Hellwig wrote: > I've mentioned this a few times before, but just to make sure it's no= t > lost: > > This is a really bad idea for adding to qemu. It's not a controller = that > actually speaks a plain SCSI protocol to disks, but a RAID controller= , that > has it's own command set for data plan operation, and minimal support= for > a few SCSI CDBs around it. I also supports passthrough channels for > CDROMs and other periphals, but using those with disks is not recomme= nded > by LSI, thus explicitly disabled in most drivers and most certainly n= ot > tested. So it fits the qemu model, especially if using scsi-generic > undeneath pretty badly and I don't think it helps us in practice. > Hmm. This driver emulates an existing piece of hardware. If the OS driver has shortcomings, okay, so be it. But are there any rules which devices might be emulated and which=20 shouldn't? Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg)