From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 3/3] megasas: LSI Megaraid SAS emulation Date: Sat, 02 Jul 2011 15:50:13 +0200 Message-ID: <4E0F2215.4040307@suse.de> References: <1309534555-22178-1-git-send-email-hare@suse.de> <1309534555-22178-2-git-send-email-hare@suse.de> <1309534555-22178-3-git-send-email-hare@suse.de> <1309534555-22178-4-git-send-email-hare@suse.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 To: Alexander Graf Return-path: Received: from cantor2.suse.de ([195.135.220.15]:43105 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753904Ab1GBLu0 (ORCPT ); Sat, 2 Jul 2011 07:50:26 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 07/01/2011 06:42 PM, Alexander Graf wrote: > > On 01.07.2011, at 17:35, Hannes Reinecke wrote: > >> This patch adds an emulation for the LSI Megaraid SAS 8708EM2 HBA. > > Have you tried to execute the current version of megasas and actually > do something with it? I just booted up openSUSE 11.4 rescue from DVD > with a megasas adapter that contained a raw file backed by tmpfs. > Creating a partition worked fine, but when running mkfs.ext3 and > mounting afterwards, the mount fails saying there is no ext3 on the = disk. > > Sounds like data corruption to me :). I know that this used to work > a while back, so it might be a regression recently? > It worked here, in the sense that I've booted up an existing openSUSE=20 11.4 installation. But I wouldn't be surprised if the degradation to us= e=20 bounce-buffers has some flaws. My guess here is that we have problems when the transfersizes larger as= =20 the internal bounce buffer. (I probably should be putting in some more references to 'bounce=20 buffers' here to alert people that using bounce buffers in SCSI is the=20 best way of killing performance) (And no, I will not getting into another dog-fight with Paul B. here. Virtio can do without bounce buffers. AHCI can. So I fail to see why=20 SCSI has to rely on bounce buffers.) But enough of this, Yeah, bugfixing is needed here. I see what I can do= =2E 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: Markus Rex, HRB 16746 (AG N=FCrnberg)