[Xen-ia64-devel] PLEASE REPLY: Poll for xen-ia64-devel readers on elilo naming

["Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>]

There are now over 70 people on the xen-ia64-devel mailing
list, but very few actively participate.  THIS IS YOUR
CHANCE TO PARTICIPATE!  Please reply-to-all to the following
with one of: A, B, C+A, C+B

BALLOT:

A) label=xen
   image=xen
   initrd=xenlinux
   module=xenlinux-initrd.img

B) label=xen
   image=xen
   module=xenlinux
   initrd=xenlinux-initrd.img

C) label=xen
   image=xen
   domain0=xenlinux
   initrd=xenlinux-initrd.img

(NOTE: If voting for C, please also vote for a second
choice (e.g. C+A or C+B) as C may not be acceptable to
the elilo developers.)

DETAILED EXPLANATION:

Xen/ia64 (like Linux/ia64) is started from elilo.efi
according to instructions in elilo.conf.  A recent
change to elilo.efi (not yet in the official release)
allows additional files to be loaded by using the
"module=" paramter in elilo.conf.

Elilo.conf, when booting Linux, has a syntax like:

   label=linux2613
   image=linux-2.6.13
   #no initrd necessary here

   label=rhel4
   image=rhel-linux.gz
   initrd=rhel-initrd.img

where label is what you specify at the elilo prompt
to select which elilo.conf entry to use.  Some
linux distributions (notably RHEL 4) require an
initrd (initial ram disk) file to successfully boot,
while others (e.g. RHEL 3) do not.

With the current version of elilo.efi (no modules), Xen
is booted using an elilo.conf as follows:

   label=xen
   image=xen
   initrd=xenlinux # booted as domain0

and there is NO WAY to specify an initial ram disk
for xenlinux. That means current Xen CANNOT boot RHEL4
with the currently released version of elilo.efi.

As you have probably seen on the list, some developers
are working on modifications to elilo.efi and Xen/ia64
to allow Xen to boot RHEL4.   To do so, a new
parameter to elilo.conf is required.  "module=" has
meaning to other bootloaders so the elilo developers have
agreed to add that parameter.  However, everyone wanting
to boot RHEL4 (or any distribution that requires an
initrd) as a domain0 on Xen/ia64 will need to update to
a new elilo.efi.

This change is also an opportunity to revisit how the
various images are specified in elilo.conf.

Choice A is backwards compatible with current Xen/ia64
but initrd= specifies a linux image when booting Xen,
whereas initrd= specifies an initrd image when booting
Linux.  Some may consider this confusing.

A) label=xen
   image=xen
   initrd=xenlinux
   module=xenlinux-initrd.img

Choice B is not backwards compatible; all existing
Xen elilo.conf files will have to change.  However,
initrd= means the same thing whether booting Xen
or Linux. 

B) label=xen
   image=xen
   module=xenlinux
   initrd=xenlinux-initrd.img

Choice C utilizes a new parameter name "domain0=".
This is probably the clearest to Xen/ia64 users,
but there's no guarantee that the elilo.efi
developers will allow this change, which is very
Xen-specific.  Even if they do, it may be some time
before it appears in a released elilo.

C) label=xen
   image=xen
   domain0=xenlinux
   initrd=xenlinux-initrd.img

If you prefer C, please vote also for a second choice,
as in C+A or C+B.

Now please hit reply-to-all and vote!

Thanks,
Dan


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