From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:50628) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RLZcs-0008Hg-U4 for qemu-devel@nongnu.org; Wed, 02 Nov 2011 08:09:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RLZcr-0001t6-C8 for qemu-devel@nongnu.org; Wed, 02 Nov 2011 08:09:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18354) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RLZcr-0001sq-42 for qemu-devel@nongnu.org; Wed, 02 Nov 2011 08:09:01 -0400 Message-ID: <4EB132D3.7070700@redhat.com> Date: Wed, 02 Nov 2011 13:08:51 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <97445662815342@192.168.2.69> <97448486715687@192.168.2.69> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Do you have a use for a tester of virtio-scsi with CD drives ? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Kevin Wolf , qemu-devel@nongnu.org, Thomas Schmitt On 11/02/2011 12:25 PM, Stefan Hajnoczi wrote: >> Now i have two drives by one option. >> xorriso -devices reports >> 0 -dev '/dev/sr0' rwrw-- : 'TSSTcorp' 'CDDVDW SH-S223B' >> 1 -dev '/dev/sr1' rwrw-- : 'QEMU ' 'QEMU DVD-ROM' >> with /dev/sr1 being an empty drive. (Is this a known bug ?) > > Off the top of my head I'd say this is an empty IDE CD-ROM drive which > is added by default. Would need to check the code to be sure though. Yes, that's correct. That empty IDE CD-ROM was the same that you were getting with virtio-blk. With virtio-blk you get a /dev/vda drive that will respond to SG_IO, so it doesn't look like a pass-through CD-ROM but it is one. >> The window where i ran qemu says: >> >> qemu: ./qemu_dir/qemu-0.15.1/hw/lsi53c895a.c:540: >> lsi_do_dma: Assertion `s->current' failed. > > That's a bug in the LSI SCSI HBA emulation or a generic SCSI emulation > problem in QEMU. I have CCed Paolo and Kevin who have recently been > working on SCSI and IDE much more than me and know more. I suggest trying with 1.0-rc (origin/master). No guarantee that it works, but definitely a lot of bugs have been fixed. It is also possible that a few new ones were introduced. I can also provide an updated version of my vmw_pvscsi device model, which is simpler and more stable than the lsi device model. Also, with 1.0-rc you can do passthrough in two ways: with scsi-generic as you did, which always uses SG_IO, and with scsi-block. scsi-block uses read+write for READ/WRITE CDBs and SG_IO for everything else. You can define a scsi-block disk like this: -drive file=/dev/sr0,if=none,id=hostcd -device scsi-block,drive=hostcd The advantage of scsi-block is that it doesn't need a bounce buffer as big as the whole request; in virtio-scsi it will not require a bounce buffer at all. From the spec I don't understand how this will fail to burn CDs. It's possible that some modes work and others don't. I planned to test this on test day (Nov 7th). > Thanks for the extensive testing. I actually suggest focussing just > on qemu.git/master because that is where developers mostly invest > their time. The data points on older versions can be interesting but > my guess is folks won't have time to debug them - instead let's make > qemu.git/master work. Agreed. Paolo