From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MsnkB-0001hI-5p for qemu-devel@nongnu.org; Tue, 29 Sep 2009 21:12:35 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Msnk6-0001bt-Hq for qemu-devel@nongnu.org; Tue, 29 Sep 2009 21:12:34 -0400 Received: from [199.232.76.173] (port=33740 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Msnk6-0001bZ-26 for qemu-devel@nongnu.org; Tue, 29 Sep 2009 21:12:30 -0400 Received: from ozlabs.org ([203.10.76.45]:41351) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1Msnk5-0001Q3-GT for qemu-devel@nongnu.org; Tue, 29 Sep 2009 21:12:29 -0400 From: Rusty Russell Date: Wed, 30 Sep 2009 10:42:21 +0930 References: <4AB7A01A.3000206@redhat.com> <200909300258.17297.rusty@rustcorp.com.au> <4AC24460.1040305@codemonkey.ws> In-Reply-To: <4AC24460.1040305@codemonkey.ws> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200909301042.22358.rusty@rustcorp.com.au> Subject: [Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: john cooper , "Michael S. Tsirkin" , john cooper , qemu-devel@nongnu.org, Avi Kivity , jens.axboe@oracle.com, Vadim Rozenfeld On Wed, 30 Sep 2009 03:01:12 am Anthony Liguori wrote: > Rusty Russell wrote: > > On Tue, 29 Sep 2009 11:25:20 pm Anthony Liguori wrote: > > > >> 2) Passing an ATA identity page is goofy. We should just pass the > >> serial number and let Linux generate the identity page. Just because > >> Linux requires this as it's user space interface, that doesn't mean that > >> other guests will (like Windows). Instead of exposing an opaque blob, > >> we should expose the information we need in a structured way. > >> > > > > I think John did this on my prompting, because it already existed as a > > defined ABI. If someone is going to make stuff up, isn't it better that > > kvm does it (some of those fields might have useful values?) than linux? > > We should expose Linux ABI quirks in the virtio ABI. Down the road, > someone may decide that there's a better way to expose things like S/N > down to userspace and then in our drivers we would have to parse the ATA > identity page in order to figure out the S/N to expose that properly > through the new interface. Moreover, there's probably an OS out there > that we already have to do that for. > > That's a pretty ugly thing to have to do. Calling the ATA IDENTIFY command a Linux ABI quirk is disingenuous. Not sure what the SCSI equiv is to get a serial number (VPD?) But if everyone is happy with 20 bytes, and John wants to do SN that way, I'll take the patch. Still, I got to learn fun stuff about the block layer! Rusty.