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[RESEND,0/1] pc-bios: Support List-Directed IPL from ECKD DASD

Message ID 20230221174548.1866861-1-jrossi@linux.ibm.com (mailing list archive)
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Series pc-bios: Support List-Directed IPL from ECKD DASD | expand

Message

Jared Rossi Feb. 21, 2023, 5:45 p.m. UTC 
From: Jared Rossi <jrossi@linux.ibm.com>

Add support for List-Directed IPL (LD-IPL) type pointers.

We check for a boot record indicating LD-IPL and use it if it is valid,
otherwise we use the CCW CDL or LDL format as usual. When a block is accessed
during IPL the block number is first calculated based on the cylinder, head,
and record numbers included in the block pointer; if LD-IPL has been initiated
then each pointer will be interpreted using the new format.

For simplicity, there is no choice presented to forcibly use CCW-IPL if LD-IPL
is available.  Because both sets of pointers ultimately go to the same
kernel/initrd, using CCW- or LD-IPL is transparent to the user.

One aspect of the user experience that does change is the availability of the
interactive boot menu when a loadparm is not specified.  For the existing
CCW-IPL, when the user does not specify a loadparm they are presented with a
list of boot options; however, this list is only written in the old style
pointers.  Therefore, if no loadparm is specified, and LD-IPL is supported, the
default boot option will be used automatically.

Jared Rossi (1):
  pc-bios: Add support for List-Directed IPL from ECKD DASD

 pc-bios/s390-ccw/bootmap.c | 157 ++++++++++++++++++++++++++++---------
 pc-bios/s390-ccw/bootmap.h |  30 ++++++-
 2 files changed, 148 insertions(+), 39 deletions(-)