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

Shannon Zhao
2015-12-15T08:49:33Z

From: Shannon Zhao <shannon.zhao@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@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