vsock: add VMADDR_CID_LOCAL definition

The VMADDR_CID_RESERVED (1) was used by VMCI, but now it is not
used anymore, so we can reuse it for local communication
(loopback) adding the new well-know CID: VMADDR_CID_LOCAL.

Cc: Jorgen Hansen <[e-mail]>
Reviewed-by: Stefan Hajnoczi <[e-mail]>
Reviewed-by: Jorgen Hansen <[e-mail]>
Signed-off-by: Stefano Garzarella <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/vm_sockets.h

···
 
 #define VMADDR_CID_HYPERVISOR 0
 
-/* This CID is specific to VMCI and can be considered reserved (even VMCI
- * doesn't use it anymore, it's a legacy value from an older release).
+/* Use this as the destination CID in an address when referring to the
+ * local communication (loopback).
+ * (This was VMADDR_CID_RESERVED, but even VMCI doesn't use it anymore,
+ * it was a legacy value from an older release).
  */
 
-#define VMADDR_CID_RESERVED 1
+#define VMADDR_CID_LOCAL 1
 
 /* Use this as the destination CID in an address when referring to the host
  * (any process other than the hypervisor).  VMCI relies on it being 2, but

net/vmw_vsock/vmci_transport.c

···
 static bool vmci_transport_stream_allow(u32 cid, u32 port)
 {
 	static const u32 non_socket_contexts[] = {
-		VMADDR_CID_RESERVED,
+		VMADDR_CID_LOCAL,
 	};
 	int i;