UEFI Support For BMI

[geedo0]

Currently, BMI only supports a legacy BIOS based boot mode for tenant images. UEFI support will be necessary moving forward because that's where the industry support is going. Here's a summary of what I've found while investigated this in Secure Cloud. Let me know if you guys have any questions.

At the very least, BMI will need to provide the UEFI based versions of PXELINUX and IPXE as the boot files during DHCP. For PXELINUX these files are syslinux.efi, ldlinux.e64, and menu.. For IPXE this is the ipxe.efi file. These can be obtained by explicitly building the efi binaries from source (They aren't default targets).

BMI can potentially configure DNSmasq to dynamically assign either BIOS or UEFI bootfiles based on a DHCP option.
See: http:https://www.syslinux.org/wiki/index.php?title=PXELINUX#UEFI
Also beware that vendors(Lenovo) don't tag these things correctly: https://tools.ietf.org/html/rfc4578

I haven't actually booted directly into a BMI image over UEFI (i.e. via sanboot). So there may be some more work on the image side to get a UEFI bootloader working.