From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53142) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGhwf-0008Iz-Uk for qemu-devel@nongnu.org; Mon, 20 Nov 2017 04:00:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eGhwa-0005bG-7r for qemu-devel@nongnu.org; Mon, 20 Nov 2017 04:00:50 -0500 Date: Mon, 20 Nov 2017 10:00:37 +0100 From: Cornelia Huck Message-ID: <20171120100037.4a694914.cohuck@redhat.com> In-Reply-To: References: <1510942228-22822-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [qemu-s390x] [PATCH for-2.11] pc-bios/s390-ccw: Fix problem with invalid virtio-scsi LUN when rebooting List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger Cc: Thomas Huth , qemu-s390x@nongnu.org, qemu-devel@nongnu.org On Mon, 20 Nov 2017 09:48:36 +0100 Christian Borntraeger wrote: > Thomas, > > does this patch help as well? > > diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile > index 6d0c2ee..2687590 100644 > --- a/pc-bios/s390-ccw/Makefile > +++ b/pc-bios/s390-ccw/Makefile > @@ -12,7 +12,7 @@ $(call set-vpath, $(SRC_PATH)/pc-bios/s390-ccw) > OBJECTS = start.o main.o bootmap.o sclp.o virtio.o virtio-scsi.o virtio-blkdev.o > QEMU_CFLAGS := $(filter -W%, $(QEMU_CFLAGS)) > QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -msoft-float > -QEMU_CFLAGS += -march=z900 -fPIE -fno-strict-aliasing > +QEMU_CFLAGS += -march=z900 -fPIE -fno-strict-aliasing -fno-zero-initialized-in-bss > QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector) > LDFLAGS += -Wl,-pie -nostdlib If this would actually enable us to kill a whole bird swarm with one stone, I'd prefer it over the patch below, nicely short though it is. I plan to pack the one or the other into s390-fixes today and rebuild. > > > > > On 11/17/2017 07:45 PM, Christian Borntraeger wrote: > > > > > > On 11/17/2017 07:10 PM, Thomas Huth wrote: > >> When rebooting a guest that has a virtio-scsi disk, the s390-ccw > >> bios sometimes bails out with an error message like this: > >> > >> ! SCSI cannot report LUNs: STATUS=02 RSPN=70 KEY=05 CODE=25 QLFR=00, sure ! > >> > >> Enabling the scsi_req* tracing in QEMU shows that the ccw bios is > >> trying to execute the REPORT LUNS SCSI command with a LUN != 0, and > >> this causes the SCSI command to fail. > >> Looks like we neither clear the BSS of the s390-ccw bios during reboot, > >> nor do we explicitly set the default_scsi_device.lun value to 0, so > >> this variable can contain random values from the OS after the reboot. > >> By setting this variable explicitly to 0, the problem is fixed and > >> the reboots always succeed. > >> > >> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1514352 > >> Signed-off-by: Thomas Huth > > > > Acked-by: Christian Borntraeger > > > > We had these things multile times in the past. The QEMU elf loader does not > > zero the BSS (it just loads the load section). Hmm, what about letting the > > BIOS zero its bss itself. IIRC the kernel does the same thing. I will have a > > look into that for 2.12. > > > > PS: Please do not forget to rebuild the bios > >> --- > >> pc-bios/s390-ccw/virtio-scsi.c | 3 ++- > >> 1 file changed, 2 insertions(+), 1 deletion(-) > >> > >> diff --git a/pc-bios/s390-ccw/virtio-scsi.c b/pc-bios/s390-ccw/virtio-scsi.c > >> index c92f5d3..4fe4b9d 100644 > >> --- a/pc-bios/s390-ccw/virtio-scsi.c > >> +++ b/pc-bios/s390-ccw/virtio-scsi.c > >> @@ -223,7 +223,8 @@ static void virtio_scsi_locate_device(VDev *vdev) > >> > >> for (target = 0; target <= vdev->config.scsi.max_target; target++) { > >> sdev->channel = channel; > >> - sdev->target = target; /* sdev->lun will be 0 here */ > >> + sdev->target = target; > >> + sdev->lun = 0; /* LUN has to be 0 for REPORT LUNS */ > >> if (!scsi_report_luns(vdev, data, sizeof(data))) { > >> if (resp.response == VIRTIO_SCSI_S_BAD_TARGET) { > >> continue; > >> > > > > >