We are getting conflicting reports on this; from others' responses it
would appear that z/VM included the ability to limit which instructions
are available to a specific virtual machine and that this was reflected
through STFLE. So it would appear that the z/OS requirement for LGR
that all potential target virtual machines be at the same level could be
met by setting source and target virtual machines to the lowest level of
z hardware in the z/VM pool.
But meeting that one LGR requirement doesn't mean that z/OS can meet all
other LGR requirements.
Gary Weinhold
On 2019-03-25 12:36 a.m., Peter Relson wrote:
<snip>
When you say Live Guest Relocation isn’t supported for a z/OS guest is the
mechanism for hiding new instructions available for a z/OS guest?
</snip>
I mean simply do not do it. z/OS will not work now, and almost certainly
will never work in the future in such an environment.
z/OS relies on the facilities available at IPL (such as those identified
by STFLE) to be available for the life of the IPL. Facilities can be
added after IPL, but cannot be taken away. If z/VM for LGR were to be able
to keep all facilities relied upon by the guest to be available when
running on the relocation target, then that would be a different story.
But of course if that were done, it would not help someone try to test
things such as "instruction limitations" by using LGR.
Peter Relson
z/OS Core Technology Design
Gary Weinhold
Senior Application Architect
DATAKINETICS | Data Performance & Optimization
Phone +1.613.523.5500 x216
Email: [email protected]
Visit us online at www.DKL.com
E-mail Notification: The information contained in this email and any attachments is confidential and may be subject to copyright or other intellectual property protection. If you are not the intended recipient, you are not authorized to use or disclose this information, and we request that you notify us by reply mail or telephone and delete the original message from your mail system.
