[OpenPower-Firmware] IPMI Boot Initiator Mailbox feature

[Samuel Mendoza-Jonas]

Hi All,

The IPMI Set/Get System Boot Options commands are currently used to
implement boot device overrides via parameter 5 (boot flags) in
Petitboot, and OpenBMC already supports these.
However as Alexander points out (here: 
https://github.com/open-power/petitboot/issues/45), the spec also
describes the use of parameter 7, the "boot initiator mailbox", the
format of which is largely up to the user.

Extending Petitboot support for this is relatively straightforward and I
have a set of patches which allow a user to set the contents of the
mailbox in the format of the Petitboot "bootdevs" configuration parameter
which allows us to set arbitrary boot orders remotely, much more fine
grained than the existing boot device overrides:
http://patchwork.ozlabs.org/project/petitboot/list/?series=79302

I've tested this locally on machines with BMCs that support parameter 7
(eg. with AMI BMCs) but this would be a great feature to include in
OpenBMC. Is there interest in adding this feature? How flexible is the
current IPMI implementation in order to add this?

My patchset includes a small script which can get and set the mailbox for
a given BMC which makes the format a bit easier to understand:
http://patchwork.ozlabs.org/patch/1006633/

Cheers,
Sam