Re: [Qemu-devel] [RFC 00/15] s390: vfio-ccw dasd ipl support

[Cornelia Huck <cohuck@redhat.com>]

On Thu,  5 Jul 2018 13:25:28 -0400
"Jason J. Herne" <jjherne@linux.ibm.com> wrote:

> This is to support booting from vfio-ccw dasd devices. We basically implement
> the real hardware ipl procedure. This allows for booting Linux guests on
> vfio-ccw devices.

Wow :)

> 
> vfio-ccw's channel program prefetch algorithm complicates ipl because most ipl
> channel programs dynamically modify themselves. Details on the ipl process and
> how we worked around this issue can be found in docs/devel/s390-dasd-ipl.txt.

Yes, that must have been a challenge.

Does this work with any dasd? Or did you concentrate on ECKD?

(yeah, I'll also read what you sent :)

> 
> Jason J. Herne (15):
>   s390 vfio-ccw: Add bootindex property and IPLB data
>   s390-bios: decouple cio setup from virtio
>   s390-bios: decouple common boot logic from virtio
>   s390-bios: Extend find_dev() for non-virtio devices
>   s390-bios: Factor finding boot device out of virtio code path
>   s390-bios: Clean up cio.h
>   s390-bios: Decouple channel i/o logic from virtio
>   s390-bios: Map low core memory
>   s390-bios: ptr2u32 and u32toptr
>   s390-bios: Support for running format-0/1 channel programs
>   s390-bios: Refactor virtio to run channel programs via cio
>   s390-bios: Use control unit type to determine boot method
>   s390-bios: Add channel command codes/structs needed for dasd-ipl
>   s390-bios: Support booting from real dasd device
>   s390-bios: Use sense ccw to ensure consistent device state at boot
>     time
> 
>  docs/devel/s390-dasd-ipl.txt     | 132 +++++++++++++++++++++
>  hw/s390x/ipl.c                   |  15 +++
>  hw/s390x/s390-ccw.c              |   9 ++
>  hw/vfio/ccw.c                    |  13 +-
>  hw/vfio/ccw.h                    |  38 ++++++
>  include/hw/s390x/s390-ccw.h      |   1 +
>  pc-bios/s390-ccw/Makefile        |   2 +-
>  pc-bios/s390-ccw/cio.c           | 181 ++++++++++++++++++++++++++++
>  pc-bios/s390-ccw/cio.h           | 150 ++++++++++++++++-------
>  pc-bios/s390-ccw/dasd-ipl.c      | 249 +++++++++++++++++++++++++++++++++++++++
>  pc-bios/s390-ccw/dasd-ipl.h      |  16 +++
>  pc-bios/s390-ccw/libc.h          |  12 ++
>  pc-bios/s390-ccw/main.c          | 162 ++++++++++++++++---------
>  pc-bios/s390-ccw/netmain.c       |   1 +
>  pc-bios/s390-ccw/s390-arch.h     | 113 ++++++++++++++++++
>  pc-bios/s390-ccw/s390-ccw.h      |   9 --
>  pc-bios/s390-ccw/virtio-blkdev.c |   1 +
>  pc-bios/s390-ccw/virtio.c        |  46 +-------
>  18 files changed, 986 insertions(+), 164 deletions(-)
>  create mode 100644 docs/devel/s390-dasd-ipl.txt
>  create mode 100644 hw/vfio/ccw.h
>  create mode 100644 pc-bios/s390-ccw/cio.c
>  create mode 100644 pc-bios/s390-ccw/dasd-ipl.c
>  create mode 100644 pc-bios/s390-ccw/dasd-ipl.h
>  create mode 100644 pc-bios/s390-ccw/s390-arch.h
>