diff -r 8e55c5c11475 xen/drivers/char/console.c
--- a/xen/drivers/char/console.c	Wed Jul 05 18:48:41 2006 +0100
+++ b/xen/drivers/char/console.c	Fri Jul 07 16:40:56 2006 +0900
@@ -217,19 +217,27 @@ static void putchar_console_ring(int c)
 static void putchar_console_ring(int c)
 {
     conring[CONRING_IDX_MASK(conringp++)] = c;
-    if ( (conringp - conringc) > CONRING_SIZE )
-        conringc = conringp - CONRING_SIZE;
 }
 
 long read_console_ring(XEN_GUEST_HANDLE(char) str, u32 *pcount, int clear)
 {
     unsigned int idx, len, max, sofar, c;
     unsigned long flags;
+    static int conringlogp = 0;
 
     max   = *pcount;
     sofar = 0;
 
-    c = conringc;
+    if (clear < 0) {
+        if ( (conringp - conringlogp) > CONRING_SIZE )
+            conringlogp = conringp - CONRING_SIZE;
+            c = conringlogp;
+    } else {
+        if ( (conringp - conringc) > CONRING_SIZE )
+            conringc = conringp - CONRING_SIZE;
+            c = conringc;
+    }
+
     while ( (c != conringp) && (sofar < max) )
     {
         idx = CONRING_IDX_MASK(c);
@@ -244,7 +252,7 @@ long read_console_ring(XEN_GUEST_HANDLE(
         c += len;
     }
 
-    if ( clear )
+    if ( clear > 0 )
     {
         spin_lock_irqsave(&console_lock, flags);
         if ( (conringp - c) > CONRING_SIZE )
@@ -252,7 +260,14 @@ long read_console_ring(XEN_GUEST_HANDLE(
         else
             conringc = c;
         spin_unlock_irqrestore(&console_lock, flags);
-    }
+    } else if ( clear < 0 ) {
+        spin_lock_irqsave(&console_lock, flags);
+        if ( (conringp - c) > CONRING_SIZE )
+            conringlogp = conringp - CONRING_SIZE;
+        else
+            conringlogp = c;
+        spin_unlock_irqrestore(&console_lock, flags);
+    }        
 
     *pcount = sofar;
     return 0;