CONFIG_KVM_BOOK3S_HV_NESTED_PMU_WORKAROUND is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc
Nested L0 host workaround for L1 KVM host PMU handling bug
configname: CONFIG_KVM_BOOK3S_HV_NESTED_PMU_WORKAROUND
Linux Kernel Configuration
└─>Virtualization
└─>Nested L0 host workaround for L1 KVM host PMU handling bug
In linux kernel since version 5.2 (release Date: 2019-07-07)
Old nested HV capable Linux guests have a bug where they don't
reflect the PMU in-use status of their L2 guest to the L0 host
while the L2 PMU registers are live. This can result in loss
of L2 PMU register state, causing perf to not work correctly in
L2 guests.
Selecting this option for the L0 host implements a workaround for
those buggy L1s which saves the L2 state, at the cost of performance
in all nested-capable guest entry/exit.
reflect the PMU in-use status of their L2 guest to the L0 host
while the L2 PMU registers are live. This can result in loss
of L2 PMU register state, causing perf to not work correctly in
L2 guests.
Selecting this option for the L0 host implements a workaround for
those buggy L1s which saves the L2 state, at the cost of performance
in all nested-capable guest entry/exit.