When re-entering the VM or synchronizing PMU state after a guest counter
overflow interrupt, evaluate whether any enabled and unmasked guest
counter has overflowed ((PMOVSSET_EL0 & PMINTENSET_EL1 & PMCNTENSET_EL0)
with PMCR_EL0.E set) and update the virtual PMU interrupt level in the
vGIC accordingly.

Signed-off-by: Colton Lewis <[email protected]>
---
 arch/arm64/kvm/pmu-direct.c | 55 +++++++++++++++++++++++++++++++++++++
 arch/arm64/kvm/pmu-emul.c   | 12 ++++++--
 arch/arm64/kvm/pmu.c        |  8 +++++-
 include/kvm/arm_pmu.h       |  2 ++
 4 files changed, 73 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/pmu-direct.c b/arch/arm64/kvm/pmu-direct.c
index 95b5a64052762..ec821aa54688f 100644
--- a/arch/arm64/kvm/pmu-direct.c
+++ b/arch/arm64/kvm/pmu-direct.c
@@ -534,6 +534,61 @@ void kvm_pmu_handle_guest_irq(u64 pmovsr)
 
        for_each_set_bit(i, (unsigned long *)&govf, 64)
                set_bit(i, (unsigned long *)__ctxt_sys_reg(&vcpu->arch.ctxt, 
PMOVSSET_EL0));
+
+       if (kvm_pmu_part_overflow_status(vcpu)) {
+               kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+
+               if (!in_nmi())
+                       kvm_vcpu_kick(vcpu);
+               else
+                       irq_work_queue(&vcpu->arch.pmu.overflow_work);
+       }
+}
+
+/**
+ * kvm_pmu_part_overflow_status() - Determine if any guest counters have 
overflowed
+ * @vcpu: Pointer to struct kvm_vcpu
+ *
+ * Determine if any guest counters have overflowed and therefore an
+ * IRQ needs to be injected into the guest. If an overflow is detected
+ * while access is VCPU_PMU_ACCESS_FREE (for example, after state
+ * restoration via KVM_SET_ONE_REG), transition the vCPU to
+ * VCPU_PMU_ACCESS_GUEST_OWNED.
+ *
+ * Return: True if there was an overflow, false otherwise
+ */
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu)
+{
+       u64 mask = kvm_vcpu_pmu_guest_counter_mask(vcpu);
+       u64 pmovs, pmint, pmcr;
+       unsigned long flags;
+       bool overflow;
+
+       local_irq_save(flags);
+       if (vcpu->arch.pmu.loaded_on_cpu &&
+           vcpu == kvm_get_running_vcpu()) {
+               u64 hw_ovf = read_sysreg(pmovsset_el0) & mask;
+
+               if (hw_ovf) {
+                       __vcpu_rmw_sys_reg(vcpu, PMOVSSET_EL0, |=, hw_ovf);
+                       write_sysreg(hw_ovf, pmovsclr_el0);
+               }
+               pmint = read_pmintenset();
+               pmcr = read_pmcr();
+       } else {
+               pmint = __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
+               pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
+       }
+
+       pmovs = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+       local_irq_restore(flags);
+
+       overflow = (pmcr & ARMV8_PMU_PMCR_E) && (mask & pmovs & pmint);
+
+       if (overflow && kvm_pmu_get_access(vcpu) == VCPU_PMU_ACCESS_FREE)
+               kvm_pmu_set_guest_owned(vcpu);
+
+       return overflow;
 }
 
 /**
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index e8195984b0373..21e2c96abfdb1 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -268,7 +268,7 @@ void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, 
u64 val)
  * counter where the values of the global enable control, PMOVSSET_EL0[n], and
  * PMINTENSET_EL1[n] are all 1.
  */
-bool kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu)
 {
        u64 reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
 
@@ -296,8 +296,14 @@ bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)
 {
        struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
        bool run_level = sregs->device_irq_level & KVM_ARM_DEV_PMU;
+       bool overflow;
 
-       return kvm_pmu_overflow_status(vcpu) != run_level;
+       if (kvm_pmu_is_partitioned(vcpu->kvm))
+               overflow = kvm_pmu_part_overflow_status(vcpu);
+       else
+               overflow = kvm_pmu_emul_overflow_status(vcpu);
+
+       return overflow != run_level;
 }
 
 /*
@@ -400,7 +406,7 @@ static void kvm_pmu_perf_overflow(struct perf_event 
*perf_event,
                kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
                                          ARMV8_PMUV3_PERFCTR_CHAIN);
 
-       if (kvm_pmu_overflow_status(vcpu)) {
+       if (kvm_pmu_emul_overflow_status(vcpu)) {
                kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 
                if (!in_nmi())
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index a8214ab52fcb5..4a3c6600b2678 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -409,12 +409,18 @@ u64 kvm_pmu_evtyper_mask(struct kvm *kvm)
 static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
 {
        struct kvm_pmu *pmu = &vcpu->arch.pmu;
+       bool overflow;
 
        if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
                return;
 
+       if (kvm_pmu_is_partitioned(vcpu->kvm))
+               overflow = kvm_pmu_part_overflow_status(vcpu);
+       else
+               overflow = kvm_pmu_emul_overflow_status(vcpu);
+
        WARN_ON(kvm_vgic_inject_irq(vcpu->kvm, vcpu, pmu->irq_num,
-                                   kvm_pmu_overflow_status(vcpu), pmu));
+                                   overflow, pmu));
 }
 
 /**
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 955f142a41b94..428a609eaf1a7 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -91,6 +91,8 @@ bool kvm_set_pmuserenr(u64 val);
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_resync_el0(void);
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu);
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu);
 
 #define kvm_vcpu_has_pmu(vcpu)                                 \
        (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PMU_V3))
-- 
2.56.0.rc1.310.g51773c2048-goog


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