add basic heartbeat debug port

diff --git a/palacios/src/devices/os_debug.c b/palacios/src/devices/os_debug.c
index f821415..954c38a 100644 (file)
--- a/palacios/src/devices/os_debug.c
+++ b/palacios/src/devices/os_debug.c
@@ -26,6 +26,7 @@
 #define BUF_SIZE 1024
 
 #define DEBUG_PORT1 0xc0c0
+#define HEARTBEAT_PORT 0x99
 
 struct debug_state {
     char debug_buf[BUF_SIZE];
@@ -48,6 +49,22 @@ static int handle_gen_write(struct guest_info * core, ushort_t port, void * src,
     return length;
 }
 
+static int handle_hb_write(struct guest_info * core, ushort_t port, void * src, uint_t length, void * priv_data) {
+    uint32_t val = 0;
+
+    if (length == 1) {
+       val = *(uint8_t *)src;
+    } else if (length == 2) {
+       val = *(uint16_t *)src;
+    } else {
+       val = *(uint32_t *)src;
+    }
+
+    V3_Print("HEARTBEAT> %x (%d)\n", val, val);
+
+    return length;
+}
+
 static int handle_hcall(struct guest_info * info, uint_t hcall_id, void * priv_data) {
     struct debug_state * state = (struct debug_state *)priv_data;
 
@@ -146,6 +163,13 @@ static int debug_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
        return -1;
     }
 
+
+    if (v3_dev_hook_io(dev, HEARTBEAT_PORT, NULL, &handle_hb_write) == -1) {
+       PrintError("error hooking OS heartbeat port\n");
+       v3_remove_device(dev);
+       return -1;
+    }
+
     v3_register_hypercall(vm, OS_DEBUG_HCALL, handle_hcall, state);
 
     state->debug_offset = 0;