PMMIR_EL1 is exposed from Linux v7.3 onwards. Backward migration to an older kernel would fail without cpreg migration tolerance definition for this register.
Since qemu does not set KVM_ARM_VCPU_PMU_V3_STRICT the guest will RAZ this register for both the old and new kernel. Signed-off-by: Sebastian Ott <[email protected]> --- target/arm/cpu64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c index 96aeb6c7a0..1547ad1cd3 100644 --- a/target/arm/cpu64.c +++ b/target/arm/cpu64.c @@ -787,6 +787,14 @@ static void kvm_arm_set_cpreg_mig_tolerances(ARMCPU *cpu) arm_register_cpreg_mig_tolerance(cpu, ARM64_SYS_REG(3, 0, 10, 2, 3), 0, 0, ToleranceNotOnBothEnds); + /* + * PMMIR_EL1 was unconditionally exposed for linux 7.3 with commit + * 453f6ff04b8d ("KVM: arm64: Expose PMMIR_EL1.SLOTS under strict + * PMUv3 UAPI"). Tolerate backward migration to an older kernel. + */ + arm_register_cpreg_mig_tolerance(cpu, ARM64_SYS_REG(3, 0, 9, 14, 6), + 0, 0, ToleranceNotOnBothEnds); + /* * KVM_REG_ARM_VENDOR_HYP_BMAP_2 pseudo FW register is exposed * from v6.15 onwards. Backward migration from a >= v6.15 to an older -- 2.56.0
