Re: [PATCH v2 4/7] s390/physmem_info: query diag500(STORAGE LIMIT) to support QEMU/KVM memory devices

David Hildenbrand
2024-10-25T10:52:10Z

On 15.10.24 17:20, Heiko Carstens wrote:
> On Tue, Oct 15, 2024 at 11:01:44AM -0400, Eric Farman wrote:
>> On Mon, 2024-10-14 at 20:43 +0200, Heiko Carstens wrote:
>>> On Mon, Oct 14, 2024 at 04:46:16PM +0200, David Hildenbrand wrote:
> ...
>>> +#define DIAG500_SC_STOR_LIMIT 4
> ...
>> I like the idea of a defined constant here instead of hardcoded, but maybe it should be placed
>> somewhere in include/uapi so that QEMU can pick it up with update-linux-headers.sh and be in sync
>> with the kernel, instead of just an equivalent definition in [1] ?
>>
>> [1] https://lore.kernel.org/qemu-devel/20241008105455.2302628-8-david@redhat.com/
>
> It is already a mess; we have already subcode 3 defined:
>
> #define KVM_S390_VIRTIO_CCW_NOTIFY 3
>
> in
>
> arch/s390/include/uapi/asm/virtio-ccw.h
>
> which for some reason is uapi. But it doesn't make sense to put the
> new subcode 4 there too. So what is the end result?
>
> Another uapi file? I think resolving this would be a project on its own.

Agreed, thanks all!

--
Cheers,

David / dhildenb