Re: [PATCH] xen: Create EFI_VENDOR directory

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.03.2021 13:34, Jason Andryuk wrote:
> On Tue, Mar 23, 2021 at 3:23 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>
>> On 22.03.2021 18:08, Andrew Cooper wrote:
>>> On 22/03/2021 15:15, Jan Beulich wrote:
>>>> On 22.03.2021 15:59, Andrew Cooper wrote:
>>>>> On 22/03/2021 14:52, Jan Beulich wrote:
>>>>>> On 22.03.2021 14:33, Jason Andryuk wrote:
>>>>>>> make install-xen fails when EFI_VENDOR is set (=fedora) with:
>>>>>>> install: cannot create regular file 
>>>>>>> '/home/user/xen/dist/install/boot/efi/efi/fedora/xen-4.15.0-rc.efi': No 
>>>>>>> such file or directory
>>>>>>>
>>>>>>> Create the EFI_VENDOR directory so xen.efi can be installed within.
>>>>>>>
>>>>>>> This removes the need for Fedora and Qubes xen.spec files to manually
>>>>>>> create the directory in advance.
>>>>>> While I'm not strictly against, I'd like to point out that it was
>>>>>> deliberate to not create this directory here. I also didn't expect
>>>>>> anyone's xen.spec to do so. Instead I'd expect the distro to create
>>>>>> it during OS installation. If this was a bad assumption, I'd prefer
>>>>>> if the commit message here could point out why such an expectation
>>>>>> won't hold in general.
>>>>> This reasoning is broken for anything other `make install DESTDIR=/` on
>>>>> a live system.
>>>>>
>>>>> It is incompatible with how RPM, deb, etc packages work.
>>>> I'm afraid I don't understand, for both of your statements. If distro
>>>> installation put in place the designated directory, there wouldn't be
>>>> any live system lacking it, and there wouldn't be any concern in the
>>>> packaging of any software.
>>>>
>>>> To take a perhaps too extreme example - packages typically expect e.g.
>>>> /usr to exist as well, don't they?
>>>
>>> No.  A buildroot starts out fully empty, by design.
>>>
>>> The packaging environment (usually a chroot) invokes `make install
>>> DESTDIR=/path/to/staging/root` so you don't interfere with any of the
>>> tools inside the environment, and the resulting tar/cpio has the
>>> buildroot stripped out of paths.
>>>
>>> The failure being discussed here is the build within the packaging
>>> environment, not the metadata which forms the final package.  Installing
>>> a deb/rpm/etc will make directories as applicable.
>>
>> Ah, I see. But then this _still_ isn't the right thing to do. In fact,
>> the package build and installation shouldn't put xen.efi in the EFI
>> partition _at all_. The build system doing so is for developers only,
>> so they don't need to invoke boot loader configuration every time they
>> rebuild and re-install. Hence the packaging build shouldn't set
>> EFI_VENDOR in the first place. There it instead should be a subsequent
>> boot loader re-configuration which picks up xen.efi from its install
>> location (under $(EFI_DIR)) and places it on the EFI partition.
> 
> On Fedora, RPMs drop EFI binaries directly into /boot/efi/EFI/fedora/.
> grub, shim, fwupdate and xen are all packaged that way.  It seems
> reasonable to have those important binaries tracked by the package
> manager.
> 
> Does SuSE populate EFI_VENDOR from EFI_DIR when some boot loader
> script is called?

Yes. And back at the time, when I consulted our EFI person, I was left
with the impression that this is the only reasonable approach. The
primary reason, as said, was that the EFI partition as a whole may get
rebuilt perhaps even from scratch at any point. Hence it's not
reasonable to expect package-managed files to live there. (This is
also expressed by us installing xen.efi into two places, which ought
to be a clear indication by itself that one of them is only to ease
things, not for packaging.)

As indicated - if the error is confusing, let's try to address it by,
perhaps, covering the case of the directory not existing also via the
"partially done" message. And the message, should that also be deemed
confusing, could maybe be dropped - I wouldn't be happy about it, but
if e.g. it was replaced by one reporting the secondary install step
was actually done, this would look acceptable.

Jan