arm64: KVM: Add access handler for PMOVSSET and PMOVSCLR register

Since the reset value of PMOVSSET and PMOVSCLR is UNKNOWN, use
reset_unknown for its reset handler. Add a handler to emulate writing
PMOVSSET or PMOVSCLR register.

When writing non-zero value to PMOVSSET, the counter and its interrupt
is enabled, kick this vcpu to sync PMU interrupt.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Author: Shannon Zhao

arch/arm64/include/asm/kvm_host.h

@@ -128,6 +128,7 @@ enum vcpu_sysreg {
 	PMCCFILTR_EL0,	/* Cycle Count Filter Register */
 	PMCNTENSET_EL0,	/* Count Enable Set Register */
 	PMINTENSET_EL1,	/* Interrupt Enable Set Register */
+	PMOVSSET_EL0,	/* Overflow Flag Status Set Register */
 
 	/* 32bit specific registers. Keep them at the end of the range */
 	DACR32_EL2,	/* Domain Access Control Register */

arch/arm64/kvm/sys_regs.c

@@ -650,6 +650,28 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	u64 mask = kvm_pmu_valid_counter_mask(vcpu);
+
+	if (!kvm_arm_pmu_v3_ready(vcpu))
+		return trap_raz_wi(vcpu, p, r);
+
+	if (p->is_write) {
+		if (r->CRm & 0x2)
+			/* accessing PMOVSSET_EL0 */
+			kvm_pmu_overflow_set(vcpu, p->regval & mask);
+		else
+			/* accessing PMOVSCLR_EL0 */
+			vcpu_sys_reg(vcpu, PMOVSSET_EL0) &= ~(p->regval & mask);
+	} else {
+		p->regval = vcpu_sys_reg(vcpu, PMOVSSET_EL0) & mask;
+	}
+
+	return true;
+}
+
 /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
 #define DBG_BCR_BVR_WCR_WVR_EL1(n)					\
 	/* DBGBVRn_EL1 */						\
@@ -857,7 +879,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  access_pmcnten, NULL, PMCNTENSET_EL0 },
 	/* PMOVSCLR_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
-	  trap_raz_wi },
+	  access_pmovs, NULL, PMOVSSET_EL0 },
 	/* PMSWINC_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
 	  trap_raz_wi },
@@ -884,7 +906,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  trap_raz_wi },
 	/* PMOVSSET_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
-	  trap_raz_wi },
+	  access_pmovs, reset_unknown, PMOVSSET_EL0 },
 
 	/* TPIDR_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
@@ -1198,7 +1220,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcnten },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcnten },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), trap_raz_wi },
+	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), access_pmovs },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
@@ -1208,6 +1230,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 9), CRm(14), Op2( 0), trap_raz_wi },
 	{ Op1( 0), CRn( 9), CRm(14), Op2( 1), access_pminten },
 	{ Op1( 0), CRn( 9), CRm(14), Op2( 2), access_pminten },
+	{ Op1( 0), CRn( 9), CRm(14), Op2( 3), access_pmovs },
 
 	{ Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, c10_PRRR },
 	{ Op1( 0), CRn(10), CRm( 2), Op2( 1), access_vm_reg, NULL, c10_NMRR },

include/kvm/arm_pmu.h

@@ -43,6 +43,7 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val);
 u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu);
 void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val);
 void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val);
+void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val);
 void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 				    u64 select_idx);
 #else
@@ -63,6 +64,7 @@ static inline u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
 }
 static inline void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val) {}
 static inline void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val) {}
+static inline void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val) {}
 static inline void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu,
 						  u64 data, u64 select_idx) {}
 #endif

virt/kvm/arm/pmu.c

@@ -149,6 +149,37 @@ void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
 	}
 }
 
+static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
+{
+	u64 reg = 0;
+
+	if ((vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+		reg = vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+		reg &= vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+		reg &= vcpu_sys_reg(vcpu, PMINTENSET_EL1);
+		reg &= kvm_pmu_valid_counter_mask(vcpu);
+
+	return reg;
+}
+
+/**
+ * kvm_pmu_overflow_set - set PMU overflow interrupt
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMOVSSET register
+ */
+void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val)
+{
+	u64 reg;
+
+	if (val == 0)
+		return;
+
+	vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= val;
+	reg = kvm_pmu_overflow_status(vcpu);
+	if (reg != 0)
+		kvm_vcpu_kick(vcpu);
+}
+
 static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx)
 {
 	return (vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) &&