I can confirm that the 2020 package from Debian 11 works with Xen, and that the 2022 package from Debian 12 is broken in interesting ways (I could start a <4G VM, but >= 4G vms instantly crashed).
I tried to update the packaging to edk2 202502, but I ran into a bug in OVMF: https://github.com/tianocore/edk2/issues/11046 I have prepared an update to the src:edk2 package based off of the last working 202408 version of edk and posted the change to enable and build ovmf-xen here: https://github.com/byteit101/edk2-debian. Note that c2c08abb36224f5a6700f12e6a16c07ad33a3fa9 is the real change. I also added on top c7b34aae3d3d873af6d57ff1d952021331c3450e which is just a "build faster" commit for testing, and shouldn't be pulled by a Debian developer. With that tree built and installed, I was able to get all my HVM machines working by specifying: firmware='ovmf' system_firmware="/usr/share/ovmf/XEN_OVMF.fd" Presumably once a DD pulls this change, the Xen package will need the ovmf build flags updated to point to the new path.
