KVM: PPC: booke: Get/set guest EPCR register using ONE_REG interface

Implement ONE_REG interface for EPCR register adding KVM_REG_PPC_EPCR to
the list of ONE_REG PPC supported registers.

Signed-off-by: Mihai Caraman <[e-mail]>
[agraf: remove HV dependency, use get/put_user]
Signed-off-by: Alexander Graf <[e-mail]>

Documentation/virtual/kvm/api.txt

···
   PPC   | KVM_REG_PPC_VPA_ADDR  | 64
   PPC   | KVM_REG_PPC_VPA_SLB   | 128
   PPC   | KVM_REG_PPC_VPA_DTL   | 128
+  PPC   | KVM_REG_PPC_EPCR	| 32
 
 4.69 KVM_GET_ONE_REG
 

arch/powerpc/include/uapi/asm/kvm.h

···
 #define KVM_REG_PPC_VPA_SLB	(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x83)
 #define KVM_REG_PPC_VPA_DTL	(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x84)
 
+#define KVM_REG_PPC_EPCR	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x85)
+
 #endif /* __LINUX_KVM_POWERPC_H */

arch/powerpc/kvm/booke.c

···
 				 &vcpu->arch.dbg_reg.dac[dac], sizeof(u64));
 		break;
 	}
+#if defined(CONFIG_64BIT)
+	case KVM_REG_PPC_EPCR:
+		r = put_user(vcpu->arch.epcr, (u32 __user *)(long)reg->addr);
+		break;
+#endif
 	default:
 		break;
 	}
···
 			     (u64 __user *)(long)reg->addr, sizeof(u64));
 		break;
 	}
+#if defined(CONFIG_64BIT)
+	case KVM_REG_PPC_EPCR: {
+		u32 new_epcr;
+		r = get_user(new_epcr, (u32 __user *)(long)reg->addr);
+		if (r == 0)
+			kvmppc_set_epcr(vcpu, new_epcr);
+		break;
+	}
+#endif
 	default:
 		break;
 	}