hyperv: process POST_MESSAGE hypercall

Add handling of POST_MESSAGE hypercall.  For that, add an interface to
regsiter a handler for the messages arrived from the guest on a
particular connection id (IOW set up a message connection in Hyper-V
speak).

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Message-Id: <20180921082217.29481-10-rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c
index 7a1c1bb..a28e724 100644
--- a/hw/hyperv/hyperv.c
+++ b/hw/hyperv/hyperv.c
@@ -455,6 +455,14 @@ int hyperv_sint_route_set_sint(HvSintRoute *sint_route)
     return event_notifier_set(&sint_route->sint_set_notifier);
 }
 
+typedef struct MsgHandler {
+    struct rcu_head rcu;
+    QLIST_ENTRY(MsgHandler) link;
+    uint32_t conn_id;
+    HvMsgHandler handler;
+    void *data;
+} MsgHandler;
+
 typedef struct EventFlagHandler {
     struct rcu_head rcu;
     QLIST_ENTRY(EventFlagHandler) link;
@@ -462,15 +470,91 @@ typedef struct EventFlagHandler {
     EventNotifier *notifier;
 } EventFlagHandler;
 
+static QLIST_HEAD(, MsgHandler) msg_handlers;
 static QLIST_HEAD(, EventFlagHandler) event_flag_handlers;
 static QemuMutex handlers_mutex;
 
 static void __attribute__((constructor)) hv_init(void)
 {
+    QLIST_INIT(&msg_handlers);
     QLIST_INIT(&event_flag_handlers);
     qemu_mutex_init(&handlers_mutex);
 }
 
+int hyperv_set_msg_handler(uint32_t conn_id, HvMsgHandler handler, void *data)
+{
+    int ret;
+    MsgHandler *mh;
+
+    qemu_mutex_lock(&handlers_mutex);
+    QLIST_FOREACH(mh, &msg_handlers, link) {
+        if (mh->conn_id == conn_id) {
+            if (handler) {
+                ret = -EEXIST;
+            } else {
+                QLIST_REMOVE_RCU(mh, link);
+                g_free_rcu(mh, rcu);
+                ret = 0;
+            }
+            goto unlock;
+        }
+    }
+
+    if (handler) {
+        mh = g_new(MsgHandler, 1);
+        mh->conn_id = conn_id;
+        mh->handler = handler;
+        mh->data = data;
+        QLIST_INSERT_HEAD_RCU(&msg_handlers, mh, link);
+        ret = 0;
+    } else {
+        ret = -ENOENT;
+    }
+unlock:
+    qemu_mutex_unlock(&handlers_mutex);
+    return ret;
+}
+
+uint16_t hyperv_hcall_post_message(uint64_t param, bool fast)
+{
+    uint16_t ret;
+    hwaddr len;
+    struct hyperv_post_message_input *msg;
+    MsgHandler *mh;
+
+    if (fast) {
+        return HV_STATUS_INVALID_HYPERCALL_CODE;
+    }
+    if (param & (__alignof__(*msg) - 1)) {
+        return HV_STATUS_INVALID_ALIGNMENT;
+    }
+
+    len = sizeof(*msg);
+    msg = cpu_physical_memory_map(param, &len, 0);
+    if (len < sizeof(*msg)) {
+        ret = HV_STATUS_INSUFFICIENT_MEMORY;
+        goto unmap;
+    }
+    if (msg->payload_size > sizeof(msg->payload)) {
+        ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
+        goto unmap;
+    }
+
+    ret = HV_STATUS_INVALID_CONNECTION_ID;
+    rcu_read_lock();
+    QLIST_FOREACH_RCU(mh, &msg_handlers, link) {
+        if (mh->conn_id == (msg->connection_id & HV_CONNECTION_ID_MASK)) {
+            ret = mh->handler(msg, mh->data);
+            break;
+        }
+    }
+    rcu_read_unlock();
+
+unmap:
+    cpu_physical_memory_unmap(msg, len, 0, 0);
+    return ret;
+}
+
 static int set_event_flag_handler(uint32_t conn_id, EventNotifier *notifier)
 {
     int ret;