[PATCH v4 10/23] KVM: arm64: Writethrough trapped PMEVTYPER register

[Colton Lewis]

With FGT in place, the remaining trapped registers need to be written
through to the underlying physical registers as well as the virtual
ones. Failing to do this means delaying when guest writes take effect.

Signed-off-by: Colton Lewis <coltonlewis at google.com>
---
 arch/arm64/kvm/sys_regs.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b3f97980b11f..704e5d45ce52 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1036,6 +1036,30 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool writethrough_pmevtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+				   u64 reg, u64 idx)
+{
+	u64 eventsel;
+
+	if (idx == ARMV8_PMU_CYCLE_IDX)
+		eventsel = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
+	else
+		eventsel = p->regval & kvm_pmu_evtyper_mask(vcpu->kvm);
+
+	if (vcpu->kvm->arch.pmu_filter &&
+	    !test_bit(eventsel, vcpu->kvm->arch.pmu_filter))
+		return false;
+
+	__vcpu_assign_sys_reg(vcpu, reg, eventsel);
+
+	if (idx == ARMV8_PMU_CYCLE_IDX)
+		write_pmccfiltr(eventsel);
+	else
+		write_pmevtypern(idx, eventsel);
+
+	return true;
+}
+
 static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			       const struct sys_reg_desc *r)
 {
@@ -1062,7 +1086,9 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	if (!pmu_counter_idx_valid(vcpu, idx))
 		return false;
 
-	if (p->is_write) {
+	if (kvm_vcpu_pmu_is_partitioned(vcpu) && p->is_write) {
+		writethrough_pmevtyper(vcpu, p, reg, idx);
+	} else if (p->is_write) {
 		kvm_pmu_set_counter_event_type(vcpu, p->regval, idx);
 		kvm_vcpu_pmu_restore_guest(vcpu);
 	} else {
-- 
2.50.0.727.gbf7dc18ff4-goog