4.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Wei Huang <[email protected]> commit 9e3f7a29694049edd728e2400ab57ad7553e5aa9 upstream. We're missing the handling code for the cycle counter accessed from a 32bit guest, leading to unexpected results. Signed-off-by: Wei Huang <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm64/kvm/sys_regs.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -602,8 +602,14 @@ static bool access_pmu_evcntr(struct kvm idx = ARMV8_PMU_CYCLE_IDX; } else { - BUG(); + return false; } + } else if (r->CRn == 0 && r->CRm == 9) { + /* PMCCNTR */ + if (pmu_access_event_counter_el0_disabled(vcpu)) + return false; + + idx = ARMV8_PMU_CYCLE_IDX; } else if (r->CRn == 14 && (r->CRm & 12) == 8) { /* PMEVCNTRn_EL0 */ if (pmu_access_event_counter_el0_disabled(vcpu)) @@ -611,7 +617,7 @@ static bool access_pmu_evcntr(struct kvm idx = ((r->CRm & 3) << 3) | (r->Op2 & 7); } else { - BUG(); + return false; } if (!pmu_counter_idx_valid(vcpu, idx))
