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| -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 ---------------------------------------------- |