Zhang, Yang Z
2010-Aug-09 13:57 UTC
[Xen-devel] [PATCH]fix_exceeding_right_shift_under_PAE
Currently, there has a logic to check whether the EPT GFN is exceeding guest
physical address width. It uses right shift(>>) to implement the check .
But the right shift count is greater than the width of the type(unsigned long =
32) under the PAE. And this will cause guest boot fail under PAE with EPT
supported.
Signed-off-by: Li Xin <xin.li@intel.com>
Signed-off-by: Zhang Yang <yang.z.zhang@intel.com>
diff -r fe930e1b2ce8 xen/arch/x86/mm/hap/p2m-ept.c
--- a/xen/arch/x86/mm/hap/p2m-ept.c Fri Aug 06 18:35:02 2010 +0100
+++ b/xen/arch/x86/mm/hap/p2m-ept.c Mon Aug 09 09:14:41 2010 +0800
@@ -267,7 +267,7 @@
* 3. passing a valid order.
*/
if ( ((gfn | mfn_x(mfn)) & ((1UL << order) - 1)) ||
- (gfn >> ((ept_get_wl(d) + 1) * EPT_TABLE_ORDER)) ||
+ ((u64)gfn >> ((ept_get_wl(d) + 1) * EPT_TABLE_ORDER)) ||
(order % EPT_TABLE_ORDER) )
return 0;
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