Re: [Qemu-devel] [PATCH 0/3] s390: Fix virtio-scsi IPL quirks

[Cornelia Huck <cohuck@redhat.com>]

On Thu,  5 Apr 2018 17:07:21 +0200
Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> wrote:

> IPL from virtio-scsi currently uses a non-standard parameter
> type definition to pass boot parameters from QEMU to the
> BIOS.
> 
> There are two potential issues with this approach:
> o If the guest operating systems requests a re-ipl of type CCW
>   where the boot device is a virtio-scsi HBA, this goes unnoticed
>   by QEMU. The BIOS will detect that it's IPLing from a SCSI
>   device, but it will boot the first LUN found, which might not
>   be the one used for the initial boot.
> o The guest operating system can be confused by an unknown
>   IPL parameter block type. If the OS hasn't previously used 
>   diag308 to store the IPL info but is changed to do so, a
>   user-observable change in behavior will happen.
> 
> The following patches address the issues above. 
> 
> Viktor Mihajlovski (3):
>   s390: Refactor IPL parameter block generation
>   s390: Ensure IPL from SCSI works as expected
>   s390: Do not pass inofficial IPL type to the guest
> 
>  hw/s390x/ipl.c             | 112 ++++++++++++++++++++++++++++++++-------------
>  pc-bios/s390-ccw/bootmap.c |   7 +++
>  pc-bios/s390-ccw/iplb.h    |  15 +++++-
>  3 files changed, 100 insertions(+), 34 deletions(-)
> 

This looks reasonable enough to queue for 2.12 (with a bios rebuild),
especially as I also plan to queue the cpu_synchronize_state() patch.
Just waiting for a R-b on the bios part.