From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Since the reset value of PMCNTENSET and PMCNTENCLR is UNKNOWN, use
reset_unknown for its reset handler. Add a handler to emulate writing
PMCNTENSET or PMCNTENCLR register.
When writing to PMCNTENSET, call perf_event_enable to enable the perf
event. When writing to PMCNTENCLR, call perf_event_disable to disable
the perf event.
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/kvm/sys_regs.c | 35 ++++++++++++++++++---
include/kvm/arm_pmu.h | 9 ++++++
virt/kvm/arm/pmu.c | 66 +++++++++++++++++++++++++++++++++++++++
4 files changed, 107 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 627f01e..e6910db 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -121,6 +121,7 @@ enum vcpu_sysreg {
PMEVCNTR0_EL0, /* Event Counter Register (0-30) */
PMEVCNTR30_EL0 = PMEVCNTR0_EL0 + 30,
PMCCNTR_EL0, /* Cycle Counter Register */
+ PMCNTENSET_EL0, /* Count Enable Set Register */
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index ff3214b..d4b6ae3 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -563,6 +563,33 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
return true;
}
+static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ u64 val, mask;
+
+ if (!kvm_arm_pmu_v3_ready(vcpu))
+ return trap_raz_wi(vcpu, p, r);
+
+ mask = kvm_pmu_valid_counter_mask(vcpu);
+ if (p->is_write) {
+ val = p->regval & mask;
+ if (r->Op2 & 0x1) {
+ /* accessing PMCNTENSET_EL0 */
+ vcpu_sys_reg(vcpu, PMCNTENSET_EL0) |= val;
+ kvm_pmu_enable_counter(vcpu, val);
+ } else {
+ /* accessing PMCNTENCLR_EL0 */
+ vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= ~val;
+ kvm_pmu_disable_counter(vcpu, val);
+ }
+ } else {
+ p->regval = vcpu_sys_reg(vcpu, PMCNTENSET_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 */ \
@@ -757,10 +784,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
access_pmcr, reset_pmcr, },
/* PMCNTENSET_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
- trap_raz_wi },
+ access_pmcnten, reset_unknown, PMCNTENSET_EL0 },
/* PMCNTENCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
- trap_raz_wi },
+ access_pmcnten, NULL, PMCNTENSET_EL0 },
/* PMOVSCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
trap_raz_wi },
@@ -1057,8 +1084,8 @@ static const struct sys_reg_desc cp15_regs[] = {
/* PMU */
{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
- { Op1( 0), CRn( 9), CRm(12), Op2( 1), trap_raz_wi },
- { Op1( 0), CRn( 9), CRm(12), Op2( 2), trap_raz_wi },
+ { 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( 5), access_pmselr },
{ Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index bcb7698..b70058e 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -40,6 +40,9 @@ struct kvm_pmu {
#define kvm_arm_pmu_v3_ready(v) ((v)->arch.pmu.ready)
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
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);
#else
struct kvm_pmu {
};
@@ -52,6 +55,12 @@ static inline u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu,
}
static inline void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu,
u64 select_idx, u64 val) {}
+static inline u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+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) {}
#endif
#endif
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index cd74e63..f8dc174 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -61,3 +61,69 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
}
+
+u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
+{
+ u64 val = vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
+
+ val &= ARMV8_PMU_PMCR_N_MASK;
+ if (val == 0)
+ return BIT(ARMV8_PMU_CYCLE_IDX);
+ else
+ return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
+}
+
+/**
+ * kvm_pmu_enable_counter - enable selected PMU counter
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMCNTENSET register
+ *
+ * Call perf_event_enable to start counting the perf event
+ */
+void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val)
+{
+ int i;
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc *pmc;
+
+ if (!(vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
+ return;
+
+ for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+ if (!(val & BIT(i)))
+ continue;
+
+ pmc = &pmu->pmc[i];
+ if (pmc->perf_event) {
+ perf_event_enable(pmc->perf_event);
+ if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
+ kvm_debug("fail to enable perf event\n");
+ }
+ }
+}
+
+/**
+ * kvm_pmu_disable_counter - disable selected PMU counter
+ * @vcpu: The vcpu pointer
+ * @val: the value guest writes to PMCNTENCLR register
+ *
+ * Call perf_event_disable to stop counting the perf event
+ */
+void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
+{
+ int i;
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+ struct kvm_pmc *pmc;
+
+ if (!val)
+ return;
+
+ for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+ if (!(val & BIT(i)))
+ continue;
+
+ pmc = &pmu->pmc[i];
+ if (pmc->perf_event)
+ perf_event_disable(pmc->perf_event);
+ }
+}
--
2.0.4
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