diff -r 463bda167715 tools/ioemu/target-i386-dm/helper2.c
--- a/tools/ioemu/target-i386-dm/helper2.c	Wed Nov 29 12:43:11 2006 +0000
+++ b/tools/ioemu/target-i386-dm/helper2.c	Wed Nov 29 14:25:16 2006 +0800
@@ -299,6 +299,10 @@ static inline void write_physical(uint64
     return cpu_physical_memory_rw((target_phys_addr_t)addr, val, size, 1);
 }
 
+#define DEBUG_BUF_SIZE 1024
+unsigned char debug_buf[DEBUG_BUF_SIZE];
+unsigned int debug_buf_idx = 0;
+
 void cpu_ioreq_pio(CPUState *env, ioreq_t *req)
 {
     int i, sign;
@@ -319,7 +323,16 @@ void cpu_ioreq_pio(CPUState *env, ioreq_
             }
         }
     } else if (req->dir == IOREQ_WRITE) {
-        if (!req->data_is_ptr) {
+        if (req->addr == 0xe9) {
+            unsigned char c = (unsigned char)req->data;
+            debug_buf[debug_buf_idx++] = c;
+            if ((debug_buf_idx == (DEBUG_BUF_SIZE - 1)) || (c == '\n'))
+            {
+                debug_buf[debug_buf_idx] = 0;
+                fprintf(logfile, "HVM DEBUG: %s", debug_buf);
+                debug_buf_idx = 0;
+            }
+        } else if (!req->data_is_ptr) {
             do_outp(env, req->addr, req->size, req->data);
         } else {
             for (i = 0; i < req->count; i++) {