Re: [RESEND PATCH 1/1] pc-bios: Add support for List-Directed IPL from ECKD DASD

[Eric Farman <farman@linux.ibm.com>]

On Fri, 2023-03-03 at 13:38 +0100, Thomas Huth wrote:
> On 21/02/2023 18.45, jrossi@linux.ibm.com wrote:
> > From: Jared Rossi <jrossi@linux.ibm.com>
> > 
> > Check for a List Directed IPL Boot Record, which would supersede
> > the CCW type
> > entries.  If the record is valid, proceed to use the new style
> > pointers
> > and perform LD-IPL. Each block pointer is interpreted as either an
> > LD-IPL
> > pointer or a legacy CCW pointer depending on the type of IPL
> > initiated.
> > 
> > In either case CCW- or LD-IPL is transparent to the user and will
> > boot the same
> > image regardless of which set of pointers is used. Because the
> > interactive boot
> > menu is only written with the old style pointers, the menu will be
> > disabled for
> > List Directed IPL from ECKD DASD.
> > 
> > If the LD-IPL fails, retry the IPL using the CCW type pointers.
> > 
> > If no LD-IPL boot record is found, simply perform CCW type IPL as
> > usual.
> > 
> > Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
> > 
> > ---
> >   pc-bios/s390-ccw/bootmap.c | 157 ++++++++++++++++++++++++++++----
> > -----
> >   pc-bios/s390-ccw/bootmap.h |  30 ++++++-
> >   2 files changed, 148 insertions(+), 39 deletions(-)
> 
>   Janosch, Jason, Eric, Christian,
> 
> could you please help with reviewing + testing this patch?

Thanks for the heads up, Thomas.

I've been using this on a z16 system with SE guests (with newer zipl to
actually write out LD-IPL data; something that should have been
mentioned here), and it seems to behave fine. I gave a quick glance
through the code, and while nothing jumped out at me this code is
rather opaque. I realize this is already queued by now but I'll still
go through it later this week so it gets another set of eyeballs.

Eric