On Thu, 7 Dec 2017 18:56:16 -0500 "Collin L. Walling" <wall...@linux.vnet.ibm.com> wrote:
> --- The Fields We Need To Store --- > > Currently, we're utilizing 3 bytes out of a 77 byte reserved field in > the IPLB for > CCW and SCSI. We do this because need a way to pass the Qemu command > line options > for a boot menu (on/off and timeout) to the s390-ccw bios. We require > only two > fields in the IPLB, totaling 3 bytes: Hm, are we actually that constrained with space? > > * uint8_t boot_menu_flag > o determines if we should show the menu or not Should be fine. I'd recommend something along the lines of - bit 0: show a boot menu - bit 1-7: reserved [for future use] > > * uint16_t boot_menu_timeout > o stored as milliseconds > o A max value of approx 65,000 gives us 65 seconds -- should be > plenty 65 seconds should be enough for everyone? :) > o could potentially be reduced to one byte, and we store the value > as seconds instead As said, do we really need to worry about the space this is using up here? > > Note: these fields *only*have value in a QEMU environment.
