KVM: PPC: bookehv: Add EPCR support in mtspr/mfspr emulation

Add EPCR support in booke mtspr/mfspr emulation. EPCR register is defined only
for 64-bit and HV categories, we will expose it at this point only to 64-bit
virtual processors running on 64-bit HV hosts.
Define a reusable setter function for vcpu's EPCR.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
[agraf: move HV dependency in the code]
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 514790f..4685b8c 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -240,7 +240,14 @@
 	case SPRN_MCSR:
 		vcpu->arch.mcsr &= ~spr_val;
 		break;
-
+#if defined(CONFIG_64BIT)
+	case SPRN_EPCR:
+		kvmppc_set_epcr(vcpu, spr_val);
+#ifdef CONFIG_KVM_BOOKE_HV
+		mtspr(SPRN_EPCR, vcpu->arch.shadow_epcr);
+#endif
+		break;
+#endif
 	default:
 		emulated = EMULATE_FAIL;
 	}
@@ -335,6 +342,11 @@
 	case SPRN_MCSR:
 		*spr_val = vcpu->arch.mcsr;
 		break;
+#if defined(CONFIG_64BIT)
+	case SPRN_EPCR:
+		*spr_val = vcpu->arch.epcr;
+		break;
+#endif
 
 	default:
 		emulated = EMULATE_FAIL;