[PATCH v7 13/19] KVM: ARM64: Add access handler for PMSWINC register

[Shannon Zhao]

From: Shannon Zhao <shannon.zhao at linaro.org>

Add access handler which emulates writing and reading PMSWINC
register and add support for creating software increment event.

Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
---
 arch/arm64/kvm/sys_regs.c | 14 +++++++++++++-
 include/kvm/arm_pmu.h     |  2 ++
 virt/kvm/arm/pmu.c        | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d1926c4..f09e500 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -690,6 +690,17 @@ static bool access_pmovsset(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static bool access_pmswinc(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			   const struct sys_reg_desc *r)
+{
+	if (p->is_write) {
+		kvm_pmu_software_increment(vcpu, p->regval);
+		return true;
+	} else {
+		return read_zero(vcpu, p);
+	}
+}
+
 /* 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 */						\
@@ -900,7 +911,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  access_pmovsset, NULL, PMOVSSET_EL0 },
 	/* PMSWINC_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
-	  trap_raz_wi },
+	  access_pmswinc, reset_unknown, PMSWINC_EL0 },
 	/* PMSELR_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b101),
 	  access_pmselr, reset_unknown, PMSELR_EL0 },
@@ -1239,6 +1250,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcntenset },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcntenset },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), access_pmovsset },
+	{ Op1( 0), CRn( 9), CRm(12), Op2( 4), access_pmswinc },
 	{ 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 },
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 93aea6a..f5888eb 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -39,6 +39,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
 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_software_increment(struct kvm_vcpu *vcpu, u64 val);
 void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 				    u64 select_idx);
 #else
@@ -52,6 +53,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
 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_software_increment(struct kvm_vcpu *vcpu, u64 val) {}
 void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 				    u64 select_idx) {}
 #endif
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 861471d..01af727 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -150,6 +150,34 @@ void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val)
 }
 
 /**
+ * kvm_pmu_software_increment - do software increment
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMSWINC register
+ */
+void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
+{
+	int i;
+	u64 type, enable, reg;
+
+	if (val == 0)
+		return;
+
+	for (i = 0; i < ARMV8_CYCLE_IDX; i++) {
+		if (!((val >> i) & 0x1))
+			continue;
+		type = vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i)
+		       & ARMV8_EVTYPE_EVENT;
+		enable = vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+		if ((type == 0) && ((enable >> i) & 0x1)) {
+			vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i)++;
+			reg = vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i);
+			if ((reg & 0xFFFFFFFF) == 0)
+				kvm_pmu_overflow_set(vcpu, BIT(i));
+		}
+	}
+}
+
+/**
  * kvm_pmu_set_counter_event_type - set selected counter to monitor some event
  * @vcpu: The vcpu pointer
  * @data: The data guest writes to PMXEVTYPER_EL0
@@ -171,6 +199,10 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 	kvm_pmu_stop_counter(vcpu, pmc);
 	eventsel = data & ARMV8_EVTYPE_EVENT;
 
+	/* For software increment event it does't need to create perf event */
+	if (eventsel == 0)
+		return;
+
 	memset(&attr, 0, sizeof(struct perf_event_attr));
 	attr.type = PERF_TYPE_RAW;
 	attr.size = sizeof(attr);
-- 
2.0.4