MIPS: KVM: Emulate RDHWR CPUNum register

Actually provide the VCPU number when emulating the RDHWR CPUNum
register, so that it will match the CPUNum field of CP0_EBase register,
rather than always returning 0.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/mips/kvm/emulate.c

@@ -2307,7 +2307,7 @@ enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc,
 		}
 		switch (rd) {
 		case MIPS_HWR_CPUNUM:		/* CPU number */
-			arch->gprs[rt] = 0;
+			arch->gprs[rt] = vcpu->vcpu_id;
 			break;
 		case MIPS_HWR_SYNCISTEP:	/* SYNCI length */
 			arch->gprs[rt] = min(current_cpu_data.dcache.linesz,