1 files changed, 91 insertions, 23 deletions

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 0012eed6d872..eb4d0730f44d 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -48,13 +48,24 @@ static struct {
         void *kvp_context; /* for the channel callback */
 } kvp_transaction;
 
+/*
+ * Before we can accept KVP messages from the host, we need
+ * to handshake with the user level daemon. This state tracks
+ * if we are in the handshake phase.
+ */
+static bool in_hand_shake = true;
+
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
+
 static void kvp_send_key(struct work_struct *dummy);
 
-#define TIMEOUT_FIRED 1
 
 static void kvp_respond_to_host(char *key, char *value, int error);
 static void kvp_work_func(struct work_struct *dummy);
-static void kvp_register(void);
+static void kvp_register(int);
 
 static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
@@ -68,7 +79,7 @@ static u8 *recv_buffer;
  */
 
 static void
-kvp_register(void)
+kvp_register(int reg_value)
 {
 
         struct cn_msg *msg;
@@ -83,7 +94,7 @@ kvp_register(void)
                 msg->id.idx =  CN_KVP_IDX;
                 msg->id.val = CN_KVP_VAL;
 
-                kvp_msg->kvp_hdr.operation = KVP_OP_REGISTER;
+                kvp_msg->kvp_hdr.operation = reg_value;
                 strcpy(version, HV_DRV_VERSION);
                 msg->len = sizeof(struct hv_kvp_msg);
                 cn_netlink_send(msg, 0, GFP_ATOMIC);
@@ -97,9 +108,43 @@ kvp_work_func(struct work_struct *dummy)
          * If the timer fires, the user-mode component has not responded;
          * process the pending transaction.
          */
-        kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED);
+        kvp_respond_to_host("Unknown key", "Guest timed out", HV_E_FAIL);
+}
+
+static int kvp_handle_handshake(struct hv_kvp_msg *msg)
+{
+        int ret = 1;
+
+        switch (msg->kvp_hdr.operation) {
+        case KVP_OP_REGISTER:
+                dm_reg_value = KVP_OP_REGISTER;
+                pr_info("KVP: IP injection functionality not available\n");
+                pr_info("KVP: Upgrade the KVP daemon\n");
+                break;
+        case KVP_OP_REGISTER1:
+                dm_reg_value = KVP_OP_REGISTER1;
+                break;
+        default:
+                pr_info("KVP: incompatible daemon\n");
+                pr_info("KVP: KVP version: %d, Daemon version: %d\n",
+                        KVP_OP_REGISTER1, msg->kvp_hdr.operation);
+                ret = 0;
+        }
+
+        if (ret) {
+                /*
+                 * We have a compatible daemon; complete the handshake.
+                 */
+                pr_info("KVP: user-mode registering done.\n");
+                kvp_register(dm_reg_value);
+                kvp_transaction.active = false;
+                if (kvp_transaction.kvp_context)
+                        hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+        }
+        return ret;
 }
 
+
 /*
  * Callback when data is received from user mode.
  */
@@ -109,27 +154,52 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 {
         struct hv_kvp_msg *message;
         struct hv_kvp_msg_enumerate *data;
+        int     error = 0;
 
         message = (struct hv_kvp_msg *)msg->data;
-        switch (message->kvp_hdr.operation) {
+
+        /*
+         * If we are negotiating the version information
+         * with the daemon; handle that first.
+         */
+
+        if (in_hand_shake) {
+                if (kvp_handle_handshake(message))
+                        in_hand_shake = false;
+                return;
+        }
+
+        /*
+         * Based on the version of the daemon, we propagate errors from the
+         * daemon differently.
+         */
+
+        data = &message->body.kvp_enum_data;
+
+        switch (dm_reg_value) {
         case KVP_OP_REGISTER:
-                pr_info("KVP: user-mode registering done.\n");
-                kvp_register();
-                kvp_transaction.active = false;
-                hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+                /*
+                 * Null string is used to pass back error condition.
+                 */
+                if (data->data.key[0] == 0)
+                        error = HV_S_CONT;
                 break;
 
-        default:
-                data = &message->body.kvp_enum_data;
+        case KVP_OP_REGISTER1:
                 /*
-                 * Complete the transaction by forwarding the key value
-                 * to the host. But first, cancel the timeout.
+                 * We use the message header information from
+                 * the user level daemon to transmit errors.
                  */
-                if (cancel_delayed_work_sync(&kvp_work))
-                        kvp_respond_to_host(data->data.key,
-                                         data->data.value,
-                                        !strlen(data->data.key));
+                error = message->error;
+                break;
         }
+
+        /*
+         * Complete the transaction by forwarding the key value
+         * to the host. But first, cancel the timeout.
+         */
+        if (cancel_delayed_work_sync(&kvp_work))
+                kvp_respond_to_host(data->data.key, data->data.value, error);
 }
 
 static void
@@ -287,6 +357,7 @@ kvp_respond_to_host(char *key, char *value, int error)
                  */
                 return;
 
+        icmsghdrp->status = error;
 
         /*
          * If the error parameter is set, terminate the host's enumeration
@@ -294,15 +365,12 @@ kvp_respond_to_host(char *key, char *value, int error)
          */
         if (error) {
                 /*
-                 * Something failed or the we have timedout;
-                 * terminate the current  host-side iteration.
+                 * Something failed or we have timedout;
+                 * terminate the current host-side iteration.
                  */
-                icmsghdrp->status = HV_S_CONT;
                 goto response_done;
         }
 
-        icmsghdrp->status = HV_S_OK;
-
         kvp_msg = (struct hv_kvp_msg *)
                         &recv_buffer[sizeof(struct vmbuspipe_hdr) +
                         sizeof(struct icmsg_hdr)];