Re: EFI and multiboot2 devlopment work for Xen

[Ian Campbell <ian.campbell@citrix.com>]

On Mon, 2013-10-21 at 20:57 +0200, Daniel Kiper wrote:
> On Mon, Oct 21, 2013 at 09:54:38AM -0400, Peter Jones wrote:
> > On Mon, Oct 21, 2013 at 02:57:56PM +0200, Daniel Kiper wrote:
> > > Hi,
> > >
> > > During work on multiboot2 protocol support for Xen it was discovered
> > > that memory map passed via relevant tag could not represent wide range
> > > of memory types available on EFI platforms. Additionally, GRUB2
> > > implementation calls ExitBootServices() on them just before jumping
> > > into loaded image. In this situation loaded system could not clearly
> > > identify reserved memory regions, EFI runtime services regions and others.
> >
> > I think you'll find that many distros are shipping patches to grub2 to
> > add a "linuxefi" command that starts the kernel through its EFISTUB
> > code.  You may want to look in to that.
> 
> I am referring to that patches in my initial email. However, I think that
> we are not able to use them directly (correct me if I am wrong) because
> Xen does not use Linux Boot protocol.

AIUI "efilinux" is somewhat badly named and does not use the Linux Boot
Protocol (i.e. the (b)zImage stuff with real mode entry point) either.
It actually loads and executes the kernel binary as a PE/COFF executable
(the native UEFI binary executable format). xen.efi is a PE/COFF binary
too and could equally well be launched by linuxefi in this way.

Ian.