From: Jun Kamada Subject: Re: [PATCH 0/5] pvSCSI (SCSI pass through) driver Date: Thu, 25 Oct 2007 10:59:31 +0900 Message-ID: <20071025105803.5A32.KAMA@jp.fujitsu.com> References: <20071024151156.E92A.KAMA@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: kama@jp.fujitsu.com, xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Keir-san, On Wed, 24 Oct 2007 08:42:38 +0100 Keir Fraser wrote: > On 24/10/07 07:22, "Jun Kamada" wrote: > > >> Anyway, the right answer is to ensure that your structures compile the same > >> whether compiled with 32-bit or 64-bit gcc. Check the structure sizes, > >> fields sizes and field offsets. > > > > You showed me two options in previous email; i.) all the shared-memory > > structures defined in vscsiif.h compile identically for 32-bit and > > 64-bit mode, ii.) to detect the frontend's 'bitness' in scsiback and > > optionally do 32-to-64 or 64-to-32 conversion. > > > > I consider that current VBD implementation takes option ii.), however > > you recommended me to take option i.) for pvSCSI driver. > > Is my understanding right? > > Yes. It was an accident we ended up with structures compiling differently on > 32- vs 64-bit. By the time we discovered it was an issue, we couldn't break > backward compatibility. I understood. I'll try to modify the pvSCSI driver by option i.). Best regards, ----- Jun Kamada