Re: [PATCH 0/2] virtio-balloon: make it spec compliant

[David Hildenbrand <david@redhat.com>]

Sorry for the late reply!

>> I understand that concern, IIUC it would imply that:
>>
>> a) In case of a hypervisor, we never ran with a Linux guest
>> b) In case of a guest, we never ran under QEMU
> 
> Or maybe VIRTIO_BALLOON_F_FREE_PAGE_HINT is set.

Right, in which case it would be according to the spec.

>> It's certainly possible, although I would assume that most other
>> implementation candidates (e.g., cloud-hypervisor) would have complained by
>> now about Linux issues.
> 
> They either set VIRTIO_BALLOON_F_FREE_PAGE_HINT or followed linux bug to
> work around.

Okay, in the latter case it would be the unofficial way of doing it.

>> What's your experience: if someone would actually implement it according to
>> the spec, would they watch out on the virtio mailing lists for changes (or
>> even be able to vote) and would be able to comment that adjusting the spec
>> to the real first implementation is wrong?
> 
> Unfortunately my experience is that it's not that likely :(

That's what I thought, unfortunately.

> 
> 
> Whatever we do, we need to take existing setups into account.
> 
> How would we do it in the spec without breaking working setups?  I guess
> we could say that both behaviours are legal.  That would still mean we
> need the qemu and linux patches, right?

That makes sense to me. Let me take a look at the patches.

-- 
Cheers,

David / dhildenb