On Tue, 4 Jul 2023 23:56:39 +0300 Michael Tokarev <m...@tls.msk.ru> wrote:
Out of curiocity, what value is it to boot a xen domU (or qemu) guest in uefi mode? I mean, bios mode is still recommended for at least commercial virt solutions such as vmware, and it works significantly faster in qemu and xen too. It is more, qemu ships minimal bios (qboot) to eliminate all boot-time cruft which is not needed in a vm most of the time.
I personally didn't really give much thought to the choice of bootloader when setting up the DomU. If I had known back then what Michael has written now, I probably would have chosen BIOS instead. Perhaps this information about the advantages of BIOS bootloaders is something that should be added to the Xen wiki.
AFAIU, things will change with Windows 11 VMs, as Windows 11 requires UEFI, unless you use some hacks. I use future tense, because Xen still lacks TPM 2.0 support.
In the end, it shouldn't really matter IMHO, because as UEFI/Ovmf is an bootloader officially supported by Xen, and as it did work in Debian until the upgrade to Bookworm, I think the general expectation is that it should continue work in Debian Bookworm. The technical solution seems to be at hand (see the closed bug reports for Redhat and Fedora), at least for somebody who knows what he/she is doing (meaning that I often feel like poking with sticks at a nuclear reactor :-).
Paul
