arm64: KVM: Add access handler for PMSWINC register

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>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 6c61a2b..4001e85 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -129,6 +129,7 @@ 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/kvm_perf_event.h b/arch/arm64/include/asm/kvm_perf_event.h
index d1c9d50..62fa60f 100644 (file)
--- a/arch/arm64/include/asm/kvm_perf_event.h
+++ b/arch/arm64/include/asm/kvm_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 (file)
--- 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 (file)
--- 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 (file)
--- 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);