From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44756) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXMYU-0007sw-9M for qemu-devel@nongnu.org; Mon, 25 Jun 2018 04:08:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXMYP-0003Ul-9D for qemu-devel@nongnu.org; Mon, 25 Jun 2018 04:08:58 -0400 Date: Mon, 25 Jun 2018 10:08:49 +0200 From: Cornelia Huck Message-ID: <20180625100849.42ebfe78.cohuck@redhat.com> In-Reply-To: <947bbba3-dcd0-7f5b-1d92-b41be764c2f5@de.ibm.com> References: <20180622194736.GA5794@roeck-us.net> <126ac556-0602-b927-58f5-cb5f65a5e0ec@de.ibm.com> <88d9afed-f91d-c320-13c8-9a93fc52b700@de.ibm.com> <947bbba3-dcd0-7f5b-1d92-b41be764c2f5@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [qemu-s390x] s390 qemu boot failure in -next List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger Cc: Guenter Roeck , Martin Schwidefsky , linux-s390@vger.kernel.org, Thomas Huth , Vasily Gorbik , Heiko Carstens , linux-kernel@vger.kernel.org, qemu-devel , qemu-s390x On Mon, 25 Jun 2018 10:02:28 +0200 Christian Borntraeger wrote: > On 06/25/2018 09:27 AM, Christian Borntraeger wrote: > > Also adding QEMU. > > > > On 06/25/2018 09:10 AM, Christian Borntraeger wrote: > >> > >> > >> On 06/22/2018 09:47 PM, Guenter Roeck wrote: > >>> Hi, > >>> > >>> starting with commit 's390/boot: make head.S and als.c be part of the > >>> decompressor only' in -next, s390 immages no longer boot in qemu. > >>> As far as I can see, the reason is that the command line is no longer > >>> passed from qemu to the kernel, which results in a panic because the > >>> root file system can not be mounted. > >>> > >>> Was this change made on purpose ? If so, is there a way to get qemu > >>> back to working ? > >> > >> Certainly not on purpose. > >> > >> Vasily, I can reproduce this with KVM and an external kernel boot of the vmlinux file (the elf file) > >> > >> e.g. > >> > >> qemu-system-s390 -enable-kvm -nographic -kernel vmlinux -append "this string no longer is command line" > >> > >> The compressed image (bzImage) seems to work fine though. > >> > >> This seems to be an unfortunate side effect of QEMUs ways to "guess" its Linux (checking for start > >> address 0x10000, which is no longer true for the vmlinux file). With the pure vmlinux elf file > >> the load address is 0x100000 as there is no unpacker. > >> > >> Guenter, can you check if arch/s390/boot/bzImage works for you as a workaround? > > > > Something like this in QEMU > > > > diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c > > index f278036fa7..14153ce880 100644 > > --- a/hw/s390x/ipl.c > > +++ b/hw/s390x/ipl.c > > @@ -187,11 +187,13 @@ static void s390_ipl_realize(DeviceState *dev, Error **errp) > > */ > > if (pentry == KERN_IMAGE_START || pentry == 0x800) { > > ipl->start_addr = KERN_IMAGE_START; > > - /* Overwrite parameters in the kernel image, which are "rom" */ > > - strcpy(rom_ptr(KERN_PARM_AREA), ipl->cmdline); > > } else { > > ipl->start_addr = pentry; > > } > > + if (ipl->cmdline) { > > + /* If there is a command line, put it in the right place */ > > + strcpy(rom_ptr(KERN_PARM_AREA), ipl->cmdline); > > + } > > > > if (ipl->initrd) { > > ram_addr_t initrd_offset; > > > > would put the command line in no matter what the start address is. > > Ideally we would do 2 changes: > - change QEMU to add a commandline to 10480 if specified > - have a way to fix the kernel elf file to still boot with older QEMUs > Agreed on both. Even if we change QEMU now (+ stable), there are many versions out there that will now fail.