Drivers: hv: util: Properly handle version negotiations.

[firefly-linux-kernel-4.4.55.git] / drivers / hv / channel_mgmt.c

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 6c8c4d34093064ac65cad16ea8cbfc191fde053e..2b8b8d4558d247c808a0a8f7f6bfd51601aa31a2 100644 (file)
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -46,37 +46,59 @@ struct vmbus_channel_message_table_entry {
  *
  * @icmsghdrp is of type &struct icmsg_hdr.
  * @negop is of type &struct icmsg_negotiate.
- * Set up and fill in default negotiate response message. This response can
- * come from both the vmbus driver and the hv_utils driver. The current api
- * will respond properly to both Windows 2008 and Windows 2008-R2 operating
- * systems.
+ * 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.
  *
  * Mainly used by Hyper-V drivers.
  */
 void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
-                              struct icmsg_negotiate *negop, u8 *buf)
+                               struct icmsg_negotiate *negop, u8 *buf,
+                               int max_fw_version, int max_srv_version)
 {
+       int icframe_vercnt;
+       int icmsg_vercnt;
+       int i;
+
        icmsghdrp->icmsgsize = 0x10;
 
        negop = (struct icmsg_negotiate *)&buf[
                sizeof(struct vmbuspipe_hdr) +
                sizeof(struct icmsg_hdr)];
 
-       if (negop->icframe_vercnt == 2 &&
-          negop->icversion_data[1].major == 3) {
-               negop->icversion_data[0].major = 3;
-               negop->icversion_data[0].minor = 0;
-               negop->icversion_data[1].major = 3;
-               negop->icversion_data[1].minor = 0;
-       } else {
-               negop->icversion_data[0].major = 1;
-               negop->icversion_data[0].minor = 0;
-               negop->icversion_data[1].major = 1;
-               negop->icversion_data[1].minor = 0;
+       icframe_vercnt = negop->icframe_vercnt;
+       icmsg_vercnt = negop->icmsg_vercnt;
+
+       /*
+        * Select the framework version number we will
+        * support.
+        */
+
+       for (i = 0; i < negop->icframe_vercnt; i++) {
+               if (negop->icversion_data[i].major <= max_fw_version)
+                       icframe_vercnt = negop->icversion_data[i].major;
+       }
+
+       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;
        }
 
+       /*
+        * Respond with the maximum 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;
 }
 
 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);