[Spike] Make UKI systemd sysext solution more robust about kairos HOT 4 OPEN

Good test for this.

• Build uki rootfs
• Pack the /usr/firmware dir into a sysext
• Remove /usr/firmware from rootfs
• Build image, add sysext under the overlay-iso dir so it gets picked by the agent on install
• Install and reboot
• systemd-stub will try to measure the sysext and pass it to the kernel in a CPIO format. This usually gets copied intot he initramfs under /.extra/sysext
• This fails under QEMU due to an error allocating pages

Hint: A way of skipping this would be to make so the agent does copy into the /EFI/kairos/active.efi.extra.d/ dir, as stub autoloads them from there. We could just store them under /EFI/kairos/sysext and make immucore move those sysext into /run/extensions on boot directly. That would skip the systemd-stub loading the files into memory to measure them. As we currently are NOT using those measurements for anything, it would be a quick workaround.

from kairos.

FYI I can confirm that the workaround works.

Manually copied the firmware.raw extension into /run/extensions and refreshed and magically all the firmware appeared correctly :D

from kairos.

lol, nice, this works on systemd-256 I was able to auto copy the firmware sysext and have it autoload on boot :D

from kairos.

Before we close this, let's bump the sizes until things break, just to know what our limit is.

from kairos.