From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46321) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmftn-0005Jf-Qj for qemu-devel@nongnu.org; Tue, 29 Aug 2017 08:45:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dmfti-0002Ui-SN for qemu-devel@nongnu.org; Tue, 29 Aug 2017 08:45:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49960) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dmfti-0002UA-IP for qemu-devel@nongnu.org; Tue, 29 Aug 2017 08:45:38 -0400 Date: Tue, 29 Aug 2017 14:45:33 +0200 From: Cornelia Huck Message-ID: <20170829144533.54891819.cohuck@redhat.com> In-Reply-To: References: <3ed8b810b6592daee6a775037ce21f850e40647d.1503667215.git.alifm@linux.vnet.ibm.com> <20170825160408.2775c8b5.cohuck@redhat.com> <00d41b2b-cf22-c9e2-8d9f-de947f4d3f18@linux.vnet.ibm.com> <20170828102214.7aad9112.cohuck@redhat.com> <20170828150653.7cdc8c5a.cohuck@redhat.com> <20170828160554.45855dfa.cohuck@redhat.com> <9b9880e4-71fd-4bc5-961b-ab0e2b298f03@linux.vnet.ibm.com> <3421f46f-fa82-ac23-b0ac-5a2acce26d41@linux.vnet.ibm.com> <20170829140429.08a1731c.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] s390-ccw: Fix alignment for CCW1 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Farhan Ali Cc: Halil Pasic , Christian Borntraeger , qemu-devel@nongnu.org, farman@linux.vnet.ibm.com, walling@linux.vnet.ibm.com On Tue, 29 Aug 2017 08:39:27 -0400 Farhan Ali wrote: > On 08/29/2017 08:04 AM, Cornelia Huck wrote: > > On Mon, 28 Aug 2017 10:28:53 -0400 > > Farhan Ali wrote: > > > >> On 08/28/2017 10:19 AM, Halil Pasic wrote: > >>> > >>> > >>> On 08/28/2017 04:15 PM, Farhan Ali wrote: > >>>> > >>>> > >>>> On 08/28/2017 10:05 AM, Cornelia Huck wrote: > >>>>>>>> It's the alignment of the CCW which causes the problem. > >>>>>>>> > >>>>>>>> The exact error message when starting the guest was: > >>>>>>>> > >>>>>>>> ! No virtio device found ! > >>>>>>>> > >>>>>>>> Since it worked for SCSI and CDL, and failed for LDL disks on that particular system, we are not really sure what caused the failure. > >>>>>>>> Debugging it further showed the CCW for LDL disks were not aligned at double word boundary. > >>>>> This is really, really odd, as the low-level ccw code is the same for > >>>>> any disk type... > >>>>> > >>>> Exactly! > >>>> > >>>>>>>> Trying the test on a different system with LDL disks worked fine, with the aligned(8) fix. > >>>>>>> Do you happen to have an old s390-ccw.img laying around in the test folder? QEMU might pick up > >>>>>>> this one (e.g. when calling it without libvirt from the command line). > >>>>>>> > >>>>>> I explicitly mention the bios to use with '-bios' option and pick up the > >>>>>> latest bios. Without the aligned fix I see the error and with the fix it > >>>>>> works fine. > >>>>> Wait, so the fix fixes it? Or am I confused now? > >>>>> > >>>> > >>>> It fixes in my system and one other system we tried on. But fails on a system where this issue was first noticed. > >>> > >>> This is very confusing. So you have tried -bios on the system > >>> where the issue was first noticed and the issue still persists > >>> despite of the fixed bios is specified? > >>> > >> Yes. > >> > >> The system where the issue was first noticed, applying the fix for the > >> bios, fixes for: > >> > >> 1) CDL disks > >> 2) SCSI disks > >> > >> But fails for LDL disk. > >> > >> On my system and one other system, the fix works for all the disk types, > >> CDL, SCSI and LDL and fixes the issue. > > > > Are you using different toolchains on the failing and the working > > systems? Does it work when you copy the bios from a working system? > > > > (Clutching at straws here...) > > > > So yesterday we realized for the failing system, the bios wasn't being > built on that system rather it was being built on a different system and > being copied over to the failing system. :/ Oh dear... the system it was built on hopefully was missing the fix, right? (I'm getting a bit paranoid here.) > > Building the bios on the failing system with the fix, resolves the issue > and we did not see anymore failures. > So I think I can safely say this patch fixes the alignment problem. Out of interest, which toolchain are you using? My rebuild is on F26.