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hercules-390 / hyperion

Hercules 390
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MVS 3.8J intermittent hangs during IPL under VM/370 with ECPS:VM active #188

Closed wably closed 7 years ago

wably commented 7 years ago

MVS will occasionally hang after message IGF992I when IPLed in a virtual machine with ECPS:VM active. The hang is very intermittent and perhaps occurs once in 10 tries.

This issue is caused by an incorrect address in ecpsvm.h of the CP field named APSTAT2 in PSA. The correct address of APSTAT2 is X'69B'. ecpsvm.h currently has the address as X'69D'.

Correcting the improper address in the define for APSTAT2 resolves the problems with MVS. This field is used by ECPS to indicate to CP when it is necessary to purge the TLB, as a well as other flag bits in that byte. In addition, the improper address was causing bits to be improperly set in a different byte in PSA, which could cause other unpredictable problems when using ECPS:VM.

Incorrect code in ecpsvm.h: / PSA + 69D : APSTAT2 - Machine check recov & PTLB Required /

define APSTAT2 0x69D

Correct code: / PSA + 69B : APSTAT2 - Machine check recov & PTLB Required /

define APSTAT2 0x69B

wably commented 7 years ago

closing; fixed by commit of 3/4/2017