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

From: David Hildenbrand
Date: Thu Oct 17 2024 - 10:37:19 EST


On 17.10.24 16:32, Alexander Gordeev wrote:
On Thu, Oct 17, 2024 at 02:07:12PM +0200, David Hildenbrand wrote:
On 17.10.24 12:00, David Hildenbrand wrote:
Well, DIAGNOSE 260 is z/VM only and DIAG 500 is KVM only. So there are
currently not really any other reasonable ways besides SCLP.

Correction: Staring at the code again, in detect_physmem_online_ranges()
we will indeed try:

a) sclp_early_read_storage_info()
b) diag260()

So why care to call diag260() in case of DIAGNOSE 500? What about the below?

void detect_physmem_online_ranges(unsigned long max_physmem_end)
{
if (!sclp_early_read_storage_info()) {
physmem_info.info_source = MEM_DETECT_SCLP_STOR_INFO;
} else if (physmem_info.info_source == MEM_DETECT_DIAG500_STOR_LIMIT) {
unsigned long online_end;

if (!sclp_early_get_memsize(&online_end)) {
physmem_info.info_source = MEM_DETECT_SCLP_READ_INFO;
add_physmem_online_range(0, online_end);
}
} else if (!diag260()) {
physmem_info.info_source = MEM_DETECT_DIAG260;
} else if (max_physmem_end) {
add_physmem_online_range(0, max_physmem_end);
}
}

Works for me, thanks!

--
Cheers,

David / dhildenb