Re: [Xen-devel] [PATCH] x86/EFI: define and use EFI_DIR make variable, defaulting to /usr/lib64/efi

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.07.12 at 11:35, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Mon, 2012-07-23 at 10:07 +0100, Jan Beulich wrote:
>> >>> On 23.07.12 at 10:43, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
>> > What is this stuff installed in /usr/lib*/efi anyway? I suppose it isn't
>> > boot time stuff (which should go in /boot or /boot/efi). 
>> 
>> It *is* boot time stuff, and is does *not* belong into /boot.
>> When putting this together, I was told that the EFI partition
>> has to be considered volatile (i.e. may get destroyed and
>> re-created at any time).
> 
> Do you have a reference for this?

Not readily; I could ask the person who told me.

> OOI what is /boot/efi for if it can be regenerated at any time?

To boot the system. As this is using the old FAT file system, it's
not really reliable in case of kernel crashes and could be
re-initialized from the EFI shell of other firmware management
operations, and hence shouldn't be used for any non-volatile data.

>>  This is why elilo.efi also has its real
>> home under /usr, not under /boot/efi.
> 
> I noticed that (at least on Debian) grub uses /usr/lib/grub/<arch>-efi
> and elilo uses /usr/lib/elilo.

It's definitely /usr/lib64/efi/elilo.efi on SLE11, so I'm afraid this
really ins't well standardized (and hence an EFI_DIR override is
warranted, yet settling on a proper default may be problematic).

> Does that mean we should be using /usr/lib/xen/efi rather than /usr/lib/efi?
> 
> What is the policy for EFI install location on RPM/LSB based systems?

Don't know.

>> > We already have EFI_MOUNTPOINT under xen/*, I think EFI_DIR under there
>> > (or in config/*) is fine also.
>> 
>> That part wasn't controversial (if generally useful), but imo it
>> shouldn't expand to an open-coded path (unless put into
>> config/x86_64.mk).
> 
> I could live with that. Unlike LIBDIR, where getting it wrong can mean
> things don't work, getting EFI_DIR wrong is merely ugly.

Not exactly - it might still mean that boot loader installation (and
update) doesn't work anymore. But getting things consistent
would be a one-time per-distro task, so ought to be manageable.

Jan


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