From: Reiji Watanabe reijiw@google.com
commit f9ea835e99bc8d049bf2a3ec8fa5a7cb4fcade23 upstream.
Currently, with VHE, KVM enables the EL0 event counting for the guest on vcpu_load() or KVM enables it as a part of the PMU register emulation process, when needed. However, in the migration case (with VHE), the same handling is lacking, as vPMU register values that were restored by userspace haven't been propagated yet (the PMU events haven't been created) at the vcpu load-time on the first KVM_RUN (kvm_vcpu_pmu_restore_guest() called from vcpu_load() on the first KVM_RUN won't do anything as events_{guest,host} of kvm_pmu_events are still zero).
So, with VHE, enable the guest's EL0 event counting on the first KVM_RUN (after the migration) when needed. More specifically, have kvm_pmu_handle_pmcr() call kvm_vcpu_pmu_restore_guest() so that kvm_pmu_handle_pmcr() on the first KVM_RUN can take care of it.
Fixes: d0c94c49792c ("KVM: arm64: Restore PMU configuration on first run") Cc: stable@vger.kernel.org Reviewed-by: Marc Zyngier maz@kernel.org Signed-off-by: Reiji Watanabe reijiw@google.com Link: https://lore.kernel.org/r/20230329023944.2488484-1-reijiw@google.com Signed-off-by: Oliver Upton oliver.upton@linux.dev Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/pmu-emul.c | 1 + arch/arm64/kvm/sys_regs.c | 1 - 2 files changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -531,6 +531,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu for_each_set_bit(i, &mask, 32) kvm_pmu_set_counter_value(vcpu, i, 0); } + kvm_vcpu_pmu_restore_guest(vcpu); }
static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx) --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -707,7 +707,6 @@ static bool access_pmcr(struct kvm_vcpu if (!kvm_supports_32bit_el0()) val |= ARMV8_PMU_PMCR_LC; kvm_pmu_handle_pmcr(vcpu, val); - kvm_vcpu_pmu_restore_guest(vcpu); } else { /* PMCR.P & PMCR.C are RAZ */ val = __vcpu_sys_reg(vcpu, PMCR_EL0)