Re: [PATCH 0/5] s390x: Add Full Boot Order Support

[Thomas Huth]

On 06/06/2024 21.22, Jared Rossi wrote:
> On 6/5/24 4:02 AM, Thomas Huth wrote:
> > On 29/05/2024 17.43, jrossi@linux.ibm.com wrote:
> > > From: Jared Rossi <jrossi@linux.ibm.com>
> > >
> > > This patch set primarily adds support for the specification of multiple boot
> > > devices, allowing for the guest to automatically use an alternative 
> > > device on
> > > a failed boot without needing to be reconfigured. It additionally 
> > > provides the
> > > ability to define the loadparm attribute on a per-device bases, which allows
> > > boot devices to use different loadparm values if needed.
> > >
> > > In brief, an IPLB is generated for each designated boot device (up to a 
> > > maximum
> > > of 8) and stored in guest memory immediately before BIOS. If a device 
> > > fails to
> > > boot, the next IPLB is retrieved and we jump back to the start of BIOS.
> > >
> > > Devices can be specified using the standard qemu device tag "bootindex" 
> > > as with
> > > other architectures. Lower number indices are tried first, with 
> > > "bootindex=0"
> > > indicating the first device to try.
> >
> > Is this supposed with multiple scsi-hd devices, too? I tried to boot a 
> > guest with two scsi disks (attached to a single virtio-scsi-ccw adapter) 
> > where only the second disk had a bootable installation, but that failed...?
> >
> >  Thomas
>
> Hi Thomas,
>
> Yes, I would expect that to work. I tried to reproduce this using a 
> non-bootable scsi disk as the first boot device and then a known-good 
> bootable scsi disk as the second boot device, with one controller.  In my 
> instance the BIOS was not able to identify the first disk as bootable and so 
> that device failed to IPL, but it did move on to the next disk after that, 
> and the guest successfully IPL'd from the second device.
>
> When you say it failed, do you mean the first disk failed to boot (as 
> expected), but then the guest died without attempting to boot from the 
> second disk?  Or did something else happen? I am either not understanding 
> your configuration or I am not understanding your error.

I did this:

 $ ./qemu-system-s390x -bios pc-bios/s390-ccw/s390-ccw.img -accel kvm \
   -device virtio-scsi-ccw  -drive if=none,id=d2,file=/tmp/bad.qcow2 \
   -device scsi-hd,drive=d2,bootindex=2 \
   -drive if=none,id=d8,file=/tmp/good.qcow2 \
   -device scsi-hd,drive=d8,bootindex=3 -m 4G -nographic
 LOADPARM=[        ]
 Using virtio-scsi.
 Using guessed DASD geometry.
 Using ECKD scheme (block size   512), CDL
 No zIPL section in IPL2 record.
 zIPL load failed.

 Trying next boot device...
 LOADPARM=[        ]
 Using virtio-scsi.
 Using guessed DASD geometry.
 Using ECKD scheme (block size   512), CDL
 No zIPL section in IPL2 record.
 zIPL load failed.

So it claims to try to load from the second disk, but it fails.
If I change the "bootindex=3" of the second disk to "bootindex=1", it boots 
perfectly fine, so I'm sure that the installation on good.qcow2 is working fine.

 Thomas