Re: [PATCH v3 11/13] x86/xen: use lazy_mmu_state when context-switching

[David Hildenbrand <david@redhat.com>]

On 24.10.25 17:51, John Paul Adrian Glaubitz wrote:
> Hi David,

Hi,

> 
> On Fri, 2025-10-24 at 17:47 +0200, David Hildenbrand wrote:
>>> Please have people test kernel changes on SPARC on real hardware. QEMU does not
>>> emulate sun4v, for example, and therefore testing in QEMU does not cover all
>>> of SPARC hardware.
>>>
>>> There are plenty of people on the debian-sparc, gentoo-sparc and sparclinux
>>> LKML mailing lists that can test kernel patches for SPARC. If SPARC-relevant
>>> changes need to be tested, please ask there and don't bury such things in a
>>> deeply nested thread in a discussion which doesn't even have SPARC in the
>>> mail subject.
>>
>> out of curiosity, do people monitor sparclinux@ for changes to actively
>> offer testing when required -- like would it be sufficient to CC
>> relevant maintainers+list (like done here) and raise in the cover letter
>> that some testing help would be appreciated?
> 
> Yes, that's definitely the case. But it should be obvious that from the subject
> of the mail that the change affects SPARC as not everyone can read every mail
> they're receiving through mailing lists.

Agreed. One would hope that people only CC the sparc mailing list + 
maintainers when there is actually something relevant in there.

Also, it would be nice if someone (e.g., the maintainer or reviewers) 
could monitor the list to spot that there is testing demand to CC the 
right people.

I guess one problem might be that nobody is getting paid to work on 
sparc I guess (I'm happy to be wrong on that one :) ).

Regarding sparc, I'll keep in mind that we might have to write a 
separate mail to the list to get some help with testing.

> 
> I'm trying to keep up, but since I'm on mailing lists for many different architectures,
> mails can slip through the cracks.

Yeah, that's understandable.

> 
> For people that want to test changes on SPARC regularly, I can also offer accounts
> on SPARC test machines running on a Solaris LDOM (logical domain) on a SPARC T4.

For example, I do have a s390x machine in an IBM cloud where I can test 
stuff. But I worked on s390x before, so I know how to test and what to 
test, and how to troubleshoot.

On sparc I'd unfortunately have a hard time even understanding whether a 
simple boot test on some machine will actually trigger what I wanted to 
test :(

-- 
Cheers

David / dhildenb