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

[Jared Rossi <jrossi@linux.ibm.com>]

On 6/7/24 2:19 AM, Thomas Huth wrote:
> 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
>

I am able to reproduce this now; I'll investigate the problem.