[PATCH 2/2] Drivers: hv: vmbus: Enable VMBus protocol versions 5.1 and 5.2

[Andrea Parri <parri.andrea@gmail.com>]

Hyper-V has added VMBus protocol versions 5.1 and 5.2 in recent release
versions.  Allow Linux guests to negotiate these new protocol versions
on versions of Hyper-V that support them.

Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
---
 drivers/hv/connection.c | 12 +++++++-----
 include/linux/hyperv.h  |  4 ++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 90a32c9d79403..d05fef3e09080 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -45,6 +45,8 @@ EXPORT_SYMBOL_GPL(vmbus_proto_version);
  * must terminate with VERSION_INVAL.
  */
 __u32 vmbus_versions[] = {
+	VERSION_WIN10_V5_2,
+	VERSION_WIN10_V5_1,
 	VERSION_WIN10_V5,
 	VERSION_WIN10,
 	VERSION_WIN8_1,
@@ -70,12 +72,12 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 	msg->vmbus_version_requested = version;
 
 	/*
-	 * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
-	 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
+	 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
+	 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
 	 * and for subsequent messages, we must use the Message Connection ID
 	 * field in the host-returned Version Response Message. And, with
-	 * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
-	 * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
+	 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
+	 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
 	 * compatibility.
 	 *
 	 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
@@ -400,7 +402,7 @@ int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
 		case HV_STATUS_INVALID_CONNECTION_ID:
 			/*
 			 * See vmbus_negotiate_version(): VMBus protocol 5.0
-			 * requires that we must use
+			 * and higher require that we must use
 			 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
 			 * Contact message, but on old hosts that only
 			 * support VMBus protocol 4.0 or lower, here we get
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 7073f1eb3618c..5ecb2ff7cc25d 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -183,6 +183,8 @@ static inline u32 hv_get_avail_to_write_percent(
  * 3 . 0  (Windows 8 R2)
  * 4 . 0  (Windows 10)
  * 5 . 0  (Newer Windows 10)
+ * 5 . 1  (Windows 10 RS4)
+ * 5 . 2  (Windows Server 2019, RS5)
  */
 
 #define VERSION_WS2008  ((0 << 16) | (13))
@@ -191,6 +193,8 @@ static inline u32 hv_get_avail_to_write_percent(
 #define VERSION_WIN8_1    ((3 << 16) | (0))
 #define VERSION_WIN10	((4 << 16) | (0))
 #define VERSION_WIN10_V5 ((5 << 16) | (0))
+#define VERSION_WIN10_V5_1 ((5 << 16) | (1))
+#define VERSION_WIN10_V5_2 ((5 << 16) | (2))
 
 #define VERSION_INVAL -1
 
-- 
2.23.0