Drivers: hv: util: Fix a bug in version negotiation code for util services

The current code picked the highest version advertised by the host. WS2012 R2
has implemented a protocol version for KVP that is not compatible with prior
protocol versions of KVP. Fix the bug in the current code by explicitly specifying
the protocol version that the guest can support.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 109 insertions, 39 deletions

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 0df7590..12ec8c8 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -48,30 +48,39 @@ struct vmbus_channel_message_table_entry {
  * @negop is of type &struct icmsg_negotiate.
  * Set up and fill in default negotiate response message.
  *
- * The max_fw_version specifies the maximum framework version that
- * we can support and max _srv_version specifies the maximum service
- * version we can support. A special value MAX_SRV_VER can be
- * specified to indicate that we can handle the maximum version
- * exposed by the host.
+ * The fw_version specifies the  framework version that
+ * we can support and srv_version specifies the service
+ * version we can support.
  *
  * Mainly used by Hyper-V drivers.
  */
-void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
+bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
 				struct icmsg_negotiate *negop, u8 *buf,
-				int max_fw_version, int max_srv_version)
+				int fw_version, int srv_version)
 {
-	int icframe_vercnt;
-	int icmsg_vercnt;
+	int icframe_major, icframe_minor;
+	int icmsg_major, icmsg_minor;
+	int fw_major, fw_minor;
+	int srv_major, srv_minor;
 	int i;
+	bool found_match = false;
 
 	icmsghdrp->icmsgsize = 0x10;
+	fw_major = (fw_version >> 16);
+	fw_minor = (fw_version & 0xFFFF);
+
+	srv_major = (srv_version >> 16);
+	srv_minor = (srv_version & 0xFFFF);
 
 	negop = (struct icmsg_negotiate *)&buf[
 		sizeof(struct vmbuspipe_hdr) +
 		sizeof(struct icmsg_hdr)];
 
-	icframe_vercnt = negop->icframe_vercnt;
-	icmsg_vercnt = negop->icmsg_vercnt;
+	icframe_major = negop->icframe_vercnt;
+	icframe_minor = 0;
+
+	icmsg_major = negop->icmsg_vercnt;
+	icmsg_minor = 0;
 
 	/*
 	 * Select the framework version number we will
@@ -79,26 +88,48 @@ void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
 	 */
 
 	for (i = 0; i < negop->icframe_vercnt; i++) {
-		if (negop->icversion_data[i].major <= max_fw_version)
-			icframe_vercnt = negop->icversion_data[i].major;
+		if ((negop->icversion_data[i].major == fw_major) &&
+		   (negop->icversion_data[i].minor == fw_minor)) {
+			icframe_major = negop->icversion_data[i].major;
+			icframe_minor = negop->icversion_data[i].minor;
+			found_match = true;
+		}
 	}
 
+	if (!found_match)
+		goto fw_error;
+
+	found_match = false;
+
 	for (i = negop->icframe_vercnt;
 		 (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
-		if (negop->icversion_data[i].major <= max_srv_version)
-			icmsg_vercnt = negop->icversion_data[i].major;
+		if ((negop->icversion_data[i].major == srv_major) &&
+		   (negop->icversion_data[i].minor == srv_minor)) {
+			icmsg_major = negop->icversion_data[i].major;
+			icmsg_minor = negop->icversion_data[i].minor;
+			found_match = true;
+		}
 	}
 
 	/*
-	 * Respond with the maximum framework and service
+	 * Respond with the framework and service
 	 * version numbers we can support.
 	 */
-	negop->icframe_vercnt = 1;
-	negop->icmsg_vercnt = 1;
-	negop->icversion_data[0].major = icframe_vercnt;
-	negop->icversion_data[0].minor = 0;
-	negop->icversion_data[1].major = icmsg_vercnt;
-	negop->icversion_data[1].minor = 0;
+
+fw_error:
+	if (!found_match) {
+		negop->icframe_vercnt = 0;
+		negop->icmsg_vercnt = 0;
+	} else {
+		negop->icframe_vercnt = 1;
+		negop->icmsg_vercnt = 1;
+	}
+
+	negop->icversion_data[0].major = icframe_major;
+	negop->icversion_data[0].minor = icframe_minor;
+	negop->icversion_data[1].major = icmsg_major;
+	negop->icversion_data[1].minor = icmsg_minor;
+	return found_match;
 }
 
 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index ed50e9e..5312720 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -29,6 +29,16 @@
 #include <linux/hyperv.h>
 
 
+/*
+ * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
+ */
+#define WIN7_SRV_MAJOR   3
+#define WIN7_SRV_MINOR   0
+#define WIN7_SRV_MAJOR_MINOR     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
+
+#define WIN8_SRV_MAJOR   4
+#define WIN8_SRV_MINOR   0
+#define WIN8_SRV_MAJOR_MINOR     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
 
 /*
  * Global state maintained for transaction that is being processed.
@@ -593,8 +603,19 @@ void hv_kvp_onchannelcallback(void *context)
 			sizeof(struct vmbuspipe_hdr)];
 
 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+			/*
+			 * We start with win8 version and if the host cannot
+			 * support that we use the previous version.
+			 */
+			if (vmbus_prep_negotiate_resp(icmsghdrp, negop,
+				 recv_buffer, UTIL_FW_MAJOR_MINOR,
+				 WIN8_SRV_MAJOR_MINOR))
+				goto done;
+
 			vmbus_prep_negotiate_resp(icmsghdrp, negop,
-				 recv_buffer, MAX_SRV_VER, MAX_SRV_VER);
+				 recv_buffer, UTIL_FW_MAJOR_MINOR,
+				 WIN7_SRV_MAJOR_MINOR);
+
 		} else {
 			kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
 				sizeof(struct vmbuspipe_hdr) +
@@ -626,6 +647,7 @@ void hv_kvp_onchannelcallback(void *context)
 			return;
 
 		}
+done:
 
 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
 			| ICMSGHDRFLAG_RESPONSE;
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 8ad5653..e4572f3 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -24,6 +24,10 @@
 #include <linux/workqueue.h>
 #include <linux/hyperv.h>
 
+#define VSS_MAJOR  5
+#define VSS_MINOR  0
+#define VSS_MAJOR_MINOR    (VSS_MAJOR << 16 | VSS_MINOR)
+
 
 
 /*
@@ -186,18 +190,8 @@ void hv_vss_onchannelcallback(void *context)
 
 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 			vmbus_prep_negotiate_resp(icmsghdrp, negop,
-				 recv_buffer, MAX_SRV_VER, MAX_SRV_VER);
-			/*
-			 * We currently negotiate the highest number the
-			 * host has presented. If this version is not
-			 * atleast 5.0, reject.
-			 */
-			negop = (struct icmsg_negotiate *)&recv_buffer[
-				sizeof(struct vmbuspipe_hdr) +
-				sizeof(struct icmsg_hdr)];
-
-			if (negop->icversion_data[1].major < 5)
-				negop->icframe_vercnt = 0;
+				 recv_buffer, UTIL_FW_MAJOR_MINOR,
+				 VSS_MAJOR_MINOR);
 		} else {
 			vss_msg = (struct hv_vss_msg *)&recv_buffer[
 				sizeof(struct vmbuspipe_hdr) +
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 2f561c5..c16164d 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -28,6 +28,18 @@
 #include <linux/reboot.h>
 #include <linux/hyperv.h>
 
+#define SHUTDOWN_MAJOR	3
+#define SHUTDOWN_MINOR  0
+#define SHUTDOWN_MAJOR_MINOR	(SHUTDOWN_MAJOR << 16 | SHUTDOWN_MINOR)
+
+#define TIMESYNCH_MAJOR	3
+#define TIMESYNCH_MINOR 0
+#define TIMESYNCH_MAJOR_MINOR	(TIMESYNCH_MAJOR << 16 | TIMESYNCH_MINOR)
+
+#define HEARTBEAT_MAJOR	3
+#define HEARTBEAT_MINOR 0
+#define HEARTBEAT_MAJOR_MINOR	(HEARTBEAT_MAJOR << 16 | HEARTBEAT_MINOR)
+
 static void shutdown_onchannelcallback(void *context);
 static struct hv_util_service util_shutdown = {
 	.util_cb = shutdown_onchannelcallback,
@@ -87,7 +99,8 @@ static void shutdown_onchannelcallback(void *context)
 
 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 			vmbus_prep_negotiate_resp(icmsghdrp, negop,
-					shut_txf_buf, MAX_SRV_VER, MAX_SRV_VER);
+					shut_txf_buf, UTIL_FW_MAJOR_MINOR,
+					SHUTDOWN_MAJOR_MINOR);
 		} else {
 			shutdown_msg =
 				(struct shutdown_msg_data *)&shut_txf_buf[
@@ -213,7 +226,8 @@ static void timesync_onchannelcallback(void *context)
 
 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 			vmbus_prep_negotiate_resp(icmsghdrp, NULL, time_txf_buf,
-						MAX_SRV_VER, MAX_SRV_VER);
+						UTIL_FW_MAJOR_MINOR,
+						TIMESYNCH_MAJOR_MINOR);
 		} else {
 			timedatap = (struct ictimesync_data *)&time_txf_buf[
 				sizeof(struct vmbuspipe_hdr) +
@@ -253,7 +267,8 @@ static void heartbeat_onchannelcallback(void *context)
 
 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 			vmbus_prep_negotiate_resp(icmsghdrp, NULL,
-				hbeat_txf_buf, MAX_SRV_VER, MAX_SRV_VER);
+				hbeat_txf_buf, UTIL_FW_MAJOR_MINOR,
+				HEARTBEAT_MAJOR_MINOR);
 		} else {
 			heartbeat_msg =
 				(struct heartbeat_msg_data *)&hbeat_txf_buf[
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index fae8bac..4994907 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -27,6 +27,14 @@
 
 #include <linux/types.h>
 
+/*
+ * Framework version for util services.
+ */
+
+#define UTIL_FW_MAJOR  3
+#define UTIL_FW_MINOR  0
+#define UTIL_FW_MAJOR_MINOR     (UTIL_FW_MAJOR << 16 | UTIL_FW_MINOR)
+
 
 /*
  * Implementation of host controlled snapshot of the guest.
@@ -1494,7 +1502,7 @@ struct hyperv_service_callback {
 };
 
 #define MAX_SRV_VER	0x7ffffff
-extern void vmbus_prep_negotiate_resp(struct icmsg_hdr *,
+extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *,
 					struct icmsg_negotiate *, u8 *, int,
 					int);