From: "Zhai, Edwin" <edwin.zhai@intel.com>
Subject: [PATCH] [PATCH] fix system crash when vmx guest startx
	or restore
Date: Fri, 14 Jul 2006 19:37:05 +0800
Message-ID: <20060714113705.GA21620@edwin-gen.ccr>
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[PATCH] fix system crash when vmx guest startx or restore
Add this safety check like alloc_l4_table
Signed-off-by: Edwin Zhai <edwin.zhai@intel.com>
Signed-off-by: Xiaohui Xin <xiaohui.xin@intel.com>

diff -r f692a0a476c5 xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c	Thu Jul 13 15:33:08 2006 +0100
+++ b/xen/arch/x86/mm.c	Fri Jul 14 17:45:28 2006 +0800
@@ -1008,6 +1008,10 @@ static int alloc_l3_table(struct page_in
     l3_pgentry_t  *pl3e;
     int            i;
 
+    /* See the code in shadow_promote() to understand why this is here. */
+    if ( (PGT_base_page_table == PGT_l3_page_table) &&
+         shadow_mode_refcounts(d) )
+        return 1;
     ASSERT(!shadow_mode_refcounts(d));
 
 #ifdef CONFIG_X86_PAE