From: Stefano Garzarella [mailto:sgarzare@redhat.com]
Sent: Tuesday, November 19, 2019 12:01 PM

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 <redacted>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 include/uapi/linux/vm_sockets.h | 8 +++++---
 net/vmw_vsock/vmci_transport.c  | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/vm_sockets.h

b/include/uapi/linux/vm_sockets.h
index 68d57c5e99bc..fd0ed7221645 100644

--- a/include/uapi/linux/vm_sockets.h
+++ b/include/uapi/linux/vm_sockets.h

@@ -99,11 +99,13 @@

 #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

diff --git a/net/vmw_vsock/vmci_transport.c

b/net/vmw_vsock/vmci_transport.c
index 644d32e43d23..4b8b1150a738 100644

--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c

@@ -648,7 +648,7 @@ static int vmci_transport_recv_dgram_cb(void *data,

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

--
2.21.0