From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/perf_event.h | 2 ++
arch/arm64/kvm/sys_regs.c | 20 +++++++++++++++++++-
include/kvm/arm_pmu.h | 2 ++
virt/kvm/arm/pmu.c | 34 ++++++++++++++++++++++++++++++++++
5 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 05f4808..de1f82d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -127,6 +127,7 @@ enum vcpu_sysreg {
PMCNTENSET_EL0, /* Count Enable Set Register */
PMINTENSET_EL1, /* Interrupt Enable Set Register */
PMOVSSET_EL0, /* Overflow Flag Status Set Register */
+ PMSWINC_EL0, /* Software Increment Register */
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index 5c77ef8..ceb14a1 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -45,6 +45,8 @@
#define ARMV8_PMU_EVTYPE_MASK 0xc80003ff /* Mask for writable bits */
#define ARMV8_PMU_EVTYPE_EVENT 0x3ff /* Mask for EVENT bits */
+#define ARMV8_PMU_EVTYPE_EVENT_SW_INCR 0 /* Software increment event */
+
/*
* Event filters for PMUv3
*/
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 6a774f9..10e5379 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -672,6 +672,23 @@ static bool access_pmovs(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)
+{
+ u64 mask;
+
+ if (!kvm_arm_pmu_v3_ready(vcpu))
+ return trap_raz_wi(vcpu, p, r);
+
+ if (p->is_write) {
+ mask = kvm_pmu_valid_counter_mask(vcpu);
+ kvm_pmu_software_increment(vcpu, p->regval & mask);
+ return true;
+ }
+
+ return false;
+}
+
/* 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 */ \
@@ -882,7 +899,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
access_pmovs, 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 },
@@ -1221,6 +1238,7 @@ static const struct sys_reg_desc cp15_regs[] = {
{ 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), access_pmovs },
+ { 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 60061da..348c4c9 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -44,6 +44,7 @@ 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_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
@@ -65,6 +66,7 @@ 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_software_increment(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
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 0232861..9fc775e 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -180,6 +180,36 @@ void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val)
kvm_vcpu_kick(vcpu);
}
+/**
+ * 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;
+
+ enable = vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+ for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
+ if (!(val & BIT(i)))
+ continue;
+ type = vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i)
+ & ARMV8_PMU_EVTYPE_EVENT;
+ if ((type == ARMV8_PMU_EVTYPE_EVENT_SW_INCR)
+ && (enable & BIT(i))) {
+ reg = vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
+ reg = lower_32_bits(reg);
+ vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
+ if (!reg)
+ kvm_pmu_overflow_set(vcpu, BIT(i));
+ }
+ }
+}
+
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) &&
@@ -208,6 +238,10 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
kvm_pmu_stop_counter(vcpu, pmc);
eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
+ /* Software increment event does't need to be backed by a perf event */
+ if (eventsel == ARMV8_PMU_EVTYPE_EVENT_SW_INCR)
+ return;
+
memset(&attr, 0, sizeof(struct perf_event_attr));
attr.type = PERF_TYPE_RAW;
attr.size = sizeof(attr);
--
2.0.4
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