There is a known "xm console" issue related with VMX. When "serial" is

enabled in script and no once uses "xm console" to read the console,
VMX boting will hang due to the buffer is full.
I added a "select" before "write". If it could not be written,
unix_write will Return immediately and it will not block the VMX
booting. With this fix, we can  make VMX's serial enable by default.

Signed-off-by: Yu Ping <ping.y.yu@intel.com>
Modified to patch xmexample.hvm. Put through xenrt on a VMX box.

Signed-off-by: James Bulpin <james@xensource.com>

diff --git a/tools/examples/xmexample.hvm b/tools/examples/xmexample.hvm
index a1b893b0d5ebbed7220f64d059d1d1f4869220a8..5cdf03dc832e072e1542d89b630970b4481f2c2a 100644 (file)
--- a/tools/examples/xmexample.hvm
+++ b/tools/examples/xmexample.hvm
@@ -130,7 +130,7 @@ vncviewer=1
 #-----------------------------------------------------------------------------
 #   serial port re-direct to pty deivce, /dev/pts/n 
 #   then xm console or minicom can connect
-#serial='pty'
+serial='pty'
 
 #----------------------------------------------------------------------------
 # enable ne2000, default = 0(use pcnet)

diff --git a/tools/ioemu/vl.c b/tools/ioemu/vl.c
index aeed28e1e2514537fbee06f4b6dd20453f5261c0..618ddc0a3171adf4353d805df5fdeb06c8c286f1 100644 (file)
--- a/tools/ioemu/vl.c
+++ b/tools/ioemu/vl.c
@@ -957,19 +957,34 @@ static CharDriverState *stdio_clients[STDIO_MAX_CLIENTS];
 
 static int unix_write(int fd, const uint8_t *buf, int len1)
 {
-    int ret, len;
+    int ret,sel_ret,len;
+    int max_fd;
+    fd_set writefds;
+    struct timeval timeout;
+
+    max_fd = fd;  
 
     len = len1;
     while (len > 0) {
-        ret = write(fd, buf, len);
-        if (ret < 0) {
-            if (errno != EINTR && errno != EAGAIN)
-                return -1;
-        } else if (ret == 0) {
-            break;
-        } else {
-            buf += ret;
-            len -= ret;
+        FD_ZERO(&writefds);
+        FD_SET(fd, &writefds);
+       timeout.tv_sec = 0;
+       timeout.tv_usec = 0;
+       sel_ret = select(max_fd + 1, NULL, &writefds, 0, &timeout);
+       if (sel_ret <= 0) {
+               /* Timeout or select error */
+            return -1;
+       } else {
+            ret = write(fd, buf, len);
+            if (ret < 0) {
+                if (errno != EINTR && errno != EAGAIN)
+                    return -1;
+            } else if (ret == 0) {
+                   break;
+            } else {
+                   buf += ret;
+                    len -= ret;
+            }
         }
     }
     return len1 - len;