Comment 0 for bug 1847590

Revision history for this message
bugproxy (bugproxy) wrote :

Description:
s390/cpumsf: Check for CPU Measurement sampling

s390 IBM z15 introduces a check if the CPU Mesurement Facility
sampling is temporarily unavailable. If this is the case return -EBUSY
and abort the setup of CPU Measuement facility sampling.

Business Value:
With z15 the CPU Measurement sampling facility hardware may be in use when the Linux kernel CPU Measurement sampling facility device driver sets up sampling. This results in loss of sampling data and has to be avoided.

With z15 the CPU Measurement facility sampling hardware indicates being in use and the linux device driver can check for this situation and can abort any hardware access.

kernel 5.4
Git Commit: 932bfc5aae08f3cb20c1c9f051542f5933710151