Re: Xen, Linux and EFI.

From: Daniel Kiper <dkiper@net-space.pl>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen@lists.fedoraproject.org, daniel.kiper@oracle.com,
	xen-devel@lists.xensource.com
Subject: Re: Xen, Linux and EFI.
Date: Thu, 12 Jul 2012 18:10:26 +0200	[thread overview]
Message-ID: <20120712161026.GA16542@router-fw-old.local.net-space.pl> (raw)
In-Reply-To: <20120711204505.GA9717@phenom.dumpdata.com>

On Wed, Jul 11, 2012 at 04:45:05PM -0400, Konrad Rzeszutek Wilk wrote:
> Hey,
>
> There has been some discussion about EFI and SecureBoot and such.
>
> Most of the time I get questions in the form of "How do I get Fedora 17
> with Xen to do EFI", I am going to concentrate on Fedora, but I think
> this applies to other distros too.
>
> >From my reading (I hadn't actually tried EFI yet), there are two ways
> to bootup a system:
>
>  - Using grub2.efi. Grub2 does the EFI API calls and calls the Xen hypervisor
>    as if there were no EFI. This means no need for the EFI calls from
>    Linux or Xen are required).
>
>
>  - Using xen.efi. Xen can be built as a PE (Portable Executable) and it can
>    boot as an EFI image. Naturally you also need to provide a configuration
>    file and here are the details on it:
>    http://xenbits.xen.org/docs/unstable/misc/efi.html
>
>    And you would also need to configure the EFI nvram to execute xen.efi
>    instead of grub2.efi.
>
>    For the Linux side, the kernel needs to make new EFI variant hypercalls.
>    Currently the SLES kernel is capable of it. The upstream Linux kernel
>    cannot do it. There were patches proposed for it:
>    http://lists.xen.org/archives/html/xen-devel/2012-02/msg02027.html
>
>    which were mostly ports of how SLES did it (And they should reflect
>    the proper ownership, which they don't have right now).
>
>    The EFI maintainer (Matthew) commented
>    http://lists.xen.org/archives/html/xen-devel/2012-02/msg00815.html
>    that he would like a better abstraction model for it. Mainly to
>    push those calls deeper down (so introduce the registration in the
>    the efi_calls). Or perhaps by providing in boot_params.efi_info.efi_systab
>    a finely crafted structure pointing to Linux functions that would
>    do the hypercalls.
>
> And there you have it. In other words it needs somebody willing to
> look at the patches as a baseline and do some exciting new work.
> I sadly don't have right now the time to address this :-(

Hmmm... It looks quite interesting. Could I get involved in EFI stuff?

Daniel