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| author | David Hildenbrand <david@redhat.com> | 2024-10-25 16:14:47 +0200 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2024-11-07 10:26:24 +0100 |
| commit | e5d94902e47e89b389d6df295b551b5ce9ee4269 (patch) | |
| tree | 5d0426e5c9ca064708d3ab4c1fa7f2490dee8495 | |
| parent | b7cfc045488e89157a0908783171abf8e6808084 (diff) | |
Documentation: s390-diag.rst: Document diag500(STORAGE LIMIT) subfunction
Let's document our new diag500 subfunction that can be implemented by
userspace.
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241025141453.1210600-3-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
| -rw-r--r-- | Documentation/virt/kvm/s390/s390-diag.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/s390/s390-diag.rst b/Documentation/virt/kvm/s390/s390-diag.rst index 48a326d41cc0..3e4f9e3bef81 100644 --- a/Documentation/virt/kvm/s390/s390-diag.rst +++ b/Documentation/virt/kvm/s390/s390-diag.rst @@ -80,6 +80,23 @@ Subcode 3 - virtio-ccw notification See also the virtio standard for a discussion of this hypercall. +Subcode 4 - storage-limit + Handled by userspace. + + After completion of the DIAGNOSE call, general register 2 will + contain the storage limit: the maximum physical address that might be + used for storage throughout the lifetime of the VM. + + The storage limit does not indicate currently usable storage, it may + include holes, standby storage and areas reserved for other means, such + as memory hotplug or virtio-mem devices. Other interfaces for detecting + actually usable storage, such as SCLP, must be used in conjunction with + this subfunction. + + Note that the storage limit can be larger, but never smaller than the + maximum storage address indicated by SCLP via the "maximum storage + increment" and the "increment size". + DIAGNOSE function code 'X'501 - KVM breakpoint ---------------------------------------------- |