Create a VM (choose "Install later" at the end of the wizard)
Go to VM details, Hardware tab, and "Add a boot option...", choose "Network"
Save and close
Start the VM
The VM only tries hard disk and cdrom and dies (and stays on screen but that's another bug...)
The VM does a PXE boot
master build $6614
stable-9 build $6600
Yea this is a mess right now. etherboot isn't compiled anymore, and there's no ipxe rom address being passed into the seabios load_bios() function, so scan_etherboot_nic() just returns nothing. First we have to get the intel.rom onto the the rootfs, then tell the firmware to use it when booting guests, and finally modify the patch (hvmloader-load-seabios-legacy-roms.patch) to pass along the address so it can scan for it.
Also this has to go in for stable-9 since it's a pretty big regression.
I managed to get hvmloader to run the intel.rom and launch ipxe, though its quite ugly and not PR-able yet. Have to clean up the code and then will submit soon.
Per 's testing, PXE boot is working properly for legacy guests on an Optiplex 7040. Closing.