KVM: PPC: BookE: Implement EPR exit

The External Proxy Facility in FSL BookE chips allows the interrupt
controller to automatically acknowledge an interrupt as soon as a
core gets its pending external interrupt delivered.

Today, user space implements the interrupt controller, so we need to
check on it during such a cycle.

This patch implements logic for user space to enable EPR exiting,
disable EPR exiting and EPR exiting itself, so that user space can
acknowledge an interrupt when an external interrupt has successfully
been delivered into the guest vcpu.

Signed-off-by: Alexander Graf <agraf@suse.de>

4 files changed, 34 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index ab49c6cf891c..8a72d59467eb 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -520,6 +520,8 @@ struct kvm_vcpu_arch {
         u8 sane;
         u8 cpu_type;
         u8 hcall_needed;
+        u8 epr_enabled;
+        u8 epr_needed;
 
         u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */
 
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 5f5f69abd281..493630e209c8 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -264,6 +264,15 @@ static inline void kvm_linear_init(void)
 {}
 #endif
 
+static inline void kvmppc_set_epr(struct kvm_vcpu *vcpu, u32 epr)
+{
+#ifdef CONFIG_KVM_BOOKE_HV
+        mtspr(SPRN_GEPR, epr);
+#elif defined(CONFIG_BOOKE)
+        vcpu->arch.epr = epr;
+#endif
+}
+
 int kvm_vcpu_ioctl_config_tlb(struct kvm_vcpu *vcpu,
                               struct kvm_config_tlb *cfg);
 int kvm_vcpu_ioctl_dirty_tlb(struct kvm_vcpu *vcpu,
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 964f4475f55c..940ec806187e 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -306,7 +306,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 {
         int allowed = 0;
         ulong msr_mask = 0;
-        bool update_esr = false, update_dear = false;
+        bool update_esr = false, update_dear = false, update_epr = false;
         ulong crit_raw = vcpu->arch.shared->critical;
         ulong crit_r1 = kvmppc_get_gpr(vcpu, 1);
         bool crit;
@@ -330,6 +330,9 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
                 keep_irq = true;
         }
 
+        if ((priority == BOOKE_IRQPRIO_EXTERNAL) && vcpu->arch.epr_enabled)
+                update_epr = true;
+
         switch (priority) {
         case BOOKE_IRQPRIO_DTLB_MISS:
         case BOOKE_IRQPRIO_DATA_STORAGE:
@@ -408,6 +411,8 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
                         set_guest_esr(vcpu, vcpu->arch.queued_esr);
                 if (update_dear == true)
                         set_guest_dear(vcpu, vcpu->arch.queued_dear);
+                if (update_epr == true)
+                        kvm_make_request(KVM_REQ_EPR_EXIT, vcpu);
 
                 new_msr &= msr_mask;
 #if defined(CONFIG_64BIT)
@@ -615,6 +620,13 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu)
                 r = 0;
         }
 
+        if (kvm_check_request(KVM_REQ_EPR_EXIT, vcpu)) {
+                vcpu->run->epr.epr = 0;
+                vcpu->arch.epr_needed = true;
+                vcpu->run->exit_reason = KVM_EXIT_EPR;
+                r = 0;
+        }
+
         return r;
 }
 
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index e2225e5b8a4c..934413cd3a1b 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -306,6 +306,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 #ifdef CONFIG_BOOKE
         case KVM_CAP_PPC_BOOKE_SREGS:
         case KVM_CAP_PPC_BOOKE_WATCHDOG:
+        case KVM_CAP_PPC_EPR:
 #else
         case KVM_CAP_PPC_SEGSTATE:
         case KVM_CAP_PPC_HIOR:
@@ -721,6 +722,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
                 for (i = 0; i < 9; ++i)
                         kvmppc_set_gpr(vcpu, 4 + i, run->papr_hcall.args[i]);
                 vcpu->arch.hcall_needed = 0;
+#ifdef CONFIG_BOOKE
+        } else if (vcpu->arch.epr_needed) {
+                kvmppc_set_epr(vcpu, run->epr.epr);
+                vcpu->arch.epr_needed = 0;
+#endif
         }
 
         r = kvmppc_vcpu_run(run, vcpu);
@@ -762,6 +768,10 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
                 r = 0;
                 vcpu->arch.papr_enabled = true;
                 break;
+        case KVM_CAP_PPC_EPR:
+                r = 0;
+                vcpu->arch.epr_enabled = cap->args[0];
+                break;
 #ifdef CONFIG_BOOKE
         case KVM_CAP_PPC_BOOKE_WATCHDOG:
                 r = 0;