Merge branch kvm-arm64/pmevtyper-filter into kvmarm/next

* kvm-arm64/pmevtyper-filter:
  : Fixes to KVM's handling of the PMUv3 exception level filtering bits
  :
  :  - NSH (count at EL2) and M (count at EL3) should be stateful when the
  :    respective EL is advertised in the ID registers but have no effect on
  :    event counting.
  :
  :  - NSU and NSK modify the event filtering of EL0 and EL1, respectively.
  :    Though the kernel may not use these bits, other KVM guests might.
  :    Implement these bits exactly as written in the pseudocode if EL3 is
  :    advertised.
  KVM: arm64: Add PMU event filter bits required if EL3 is implemented
  KVM: arm64: Make PMEVTYPER<n>_EL0.NSH RES0 if EL2 isn't advertised
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/kvm/pmu-emul.c

@@ -60,6 +60,23 @@ static u32 kvm_pmu_event_mask(struct kvm *kvm)
 	return __kvm_pmu_event_mask(pmuver);
 }
 
+u64 kvm_pmu_evtyper_mask(struct kvm *kvm)
+{
+	u64 mask = ARMV8_PMU_EXCLUDE_EL1 | ARMV8_PMU_EXCLUDE_EL0 |
+		   kvm_pmu_event_mask(kvm);
+	u64 pfr0 = IDREG(kvm, SYS_ID_AA64PFR0_EL1);
+
+	if (SYS_FIELD_GET(ID_AA64PFR0_EL1, EL2, pfr0))
+		mask |= ARMV8_PMU_INCLUDE_EL2;
+
+	if (SYS_FIELD_GET(ID_AA64PFR0_EL1, EL3, pfr0))
+		mask |= ARMV8_PMU_EXCLUDE_NS_EL0 |
+			ARMV8_PMU_EXCLUDE_NS_EL1 |
+			ARMV8_PMU_EXCLUDE_EL3;
+
+	return mask;
+}
+
 /**
  * kvm_pmc_is_64bit - determine if counter is 64bit
  * @pmc: counter context
@@ -584,6 +601,7 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
 	struct perf_event *event;
 	struct perf_event_attr attr;
 	u64 eventsel, reg, data;
+	bool p, u, nsk, nsu;
 
 	reg = counter_index_to_evtreg(pmc->idx);
 	data = __vcpu_sys_reg(vcpu, reg);
@@ -610,13 +628,18 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
 	    !test_bit(eventsel, vcpu->kvm->arch.pmu_filter))
 		return;
 
+	p = data & ARMV8_PMU_EXCLUDE_EL1;
+	u = data & ARMV8_PMU_EXCLUDE_EL0;
+	nsk = data & ARMV8_PMU_EXCLUDE_NS_EL1;
+	nsu = data & ARMV8_PMU_EXCLUDE_NS_EL0;
+
 	memset(&attr, 0, sizeof(struct perf_event_attr));
 	attr.type = arm_pmu->pmu.type;
 	attr.size = sizeof(attr);
 	attr.pinned = 1;
 	attr.disabled = !kvm_pmu_counter_is_enabled(pmc);
-	attr.exclude_user = data & ARMV8_PMU_EXCLUDE_EL0 ? 1 : 0;
-	attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
+	attr.exclude_user = (u != nsu);
+	attr.exclude_kernel = (p != nsk);
 	attr.exclude_hv = 1; /* Don't count EL2 events */
 	attr.exclude_host = 1; /* Don't count host events */
 	attr.config = eventsel;
@@ -657,18 +680,13 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 				    u64 select_idx)
 {
 	struct kvm_pmc *pmc = kvm_vcpu_idx_to_pmc(vcpu, select_idx);
-	u64 reg, mask;
+	u64 reg;
 
 	if (!kvm_vcpu_has_pmu(vcpu))
 		return;
 
-	mask  =  ARMV8_PMU_EVTYPE_MASK;
-	mask &= ~ARMV8_PMU_EVTYPE_EVENT;
-	mask |= kvm_pmu_event_mask(vcpu->kvm);
-
 	reg = counter_index_to_evtreg(pmc->idx);
-
-	__vcpu_sys_reg(vcpu, reg) = data & mask;
+	__vcpu_sys_reg(vcpu, reg) = data & kvm_pmu_evtyper_mask(vcpu->kvm);
 
 	kvm_pmu_create_perf_event(pmc);
 }

arch/arm64/kvm/sys_regs.c

@@ -746,8 +746,12 @@ static u64 reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 
 static u64 reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
+	/* This thing will UNDEF, who cares about the reset value? */
+	if (!kvm_vcpu_has_pmu(vcpu))
+		return 0;
+
 	reset_unknown(vcpu, r);
-	__vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_EVTYPE_MASK;
+	__vcpu_sys_reg(vcpu, r->reg) &= kvm_pmu_evtyper_mask(vcpu->kvm);
 
 	return __vcpu_sys_reg(vcpu, r->reg);
 }
@@ -988,7 +992,7 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		kvm_pmu_set_counter_event_type(vcpu, p->regval, idx);
 		kvm_vcpu_pmu_restore_guest(vcpu);
 	} else {
-		p->regval = __vcpu_sys_reg(vcpu, reg) & ARMV8_PMU_EVTYPE_MASK;
+		p->regval = __vcpu_sys_reg(vcpu, reg);
 	}
 
 	return true;

include/kvm/arm_pmu.h

@@ -101,6 +101,7 @@ void kvm_vcpu_pmu_resync_el0(void);
 })
 
 u8 kvm_arm_pmu_get_pmuver_limit(void);
+u64 kvm_pmu_evtyper_mask(struct kvm *kvm);
 
 #else
 struct kvm_pmu {
@@ -172,6 +173,10 @@ static inline u8 kvm_arm_pmu_get_pmuver_limit(void)
 {
 	return 0;
 }
+static inline u64 kvm_pmu_evtyper_mask(struct kvm *kvm)
+{
+	return 0;
+}
 static inline void kvm_vcpu_pmu_resync_el0(void) {}
 
 #endif

include/linux/perf/arm_pmuv3.h

@@ -234,9 +234,12 @@
 /*
  * Event filters for PMUv3
  */
-#define ARMV8_PMU_EXCLUDE_EL1	(1U << 31)
-#define ARMV8_PMU_EXCLUDE_EL0	(1U << 30)
-#define ARMV8_PMU_INCLUDE_EL2	(1U << 27)
+#define ARMV8_PMU_EXCLUDE_EL1		(1U << 31)
+#define ARMV8_PMU_EXCLUDE_EL0		(1U << 30)
+#define ARMV8_PMU_EXCLUDE_NS_EL1	(1U << 29)
+#define ARMV8_PMU_EXCLUDE_NS_EL0	(1U << 28)
+#define ARMV8_PMU_INCLUDE_EL2		(1U << 27)
+#define ARMV8_PMU_EXCLUDE_EL3		(1U << 26)
 
 /*
  * PMUSERENR: user enable reg