Re: [Qemu-devel] [ipxe-devel] [PATCH ipxe] build: Enable IPv6 for qemu

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> How common is it to build EFI roms, compared to building ipxe.efi or
> snponly.efi?

No idea.  qemu is a very specific case, ipxe has drivers for the qemu
nics (both virtual such as virtio-net and emulated such as rtl8139), and
right now we actually build ipxe tree times (bios, efi-ia32,
efi-x86_64), then combine them into a single image, using EfiRom
(shipped with edk2).  That image is populated to the guest via pci rom
bar.  That way both seabios and ovmf (edk2 firmware for qemu) have
drivers available.

How much bios vs. efi is used -- I don't know.  seabios is the default
and has been for years, so it is pretty clear that seabios takes the
lead.  But whenever uefi share is at 1% or 10% -- no idea.

Probably we'll go add efi-aarch64 roms to the mix once ipxe support is
there, or maybe drop efi-ia32 in favor of efi-aarch64.

> On IRC, roms is quite rare topic compared to non rom builds, but maybe
> that's because those that build roms don't have that many questions.

I suspect it is because it rarely happens.  For onboard nics there
simply is no rom you can easily populate.  Instead the nic rom is stored
in the firmware flash, together with bios/uefi.  Chainloading ipxe.efi
is *alot* simpler than hacking your firmware flash.

Add-on cards are a different story of course, but I suspect >90% of the
use cases are with onboard nics.

The only case where I personally had a ipxe rom running on physical
hardware was when I flashed a T60 Thinkpad (hardware broke meanwhile)
with coreboot.

qemu has a defined set of hardware and prebuilt roms are shipped with
both qemu and distros.  So people rarely have to build qemu roms
themself -> no irc questions either ;)

cheers,
  Gerd