vtd: During parsing DMAR table, if find RMRR is incorrect, return error.

Signed-off-by: Weidong Han <weidong.han@intel.com>
xen-unstable changeset: 18114:ba6be1571cc628298c5a0666f261b660fdcaeac0
xen-unstable date: Wed Jul 23 09:58:48 2008 +0100

diff -r c8c4c8fcd6fd -r 13c740aa445f xen/arch/x86/hvm/vmx/vtd/dmar.c
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.c	Fri Jul 25 19:20:02 2008 +0800
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.c	Fri Jul 25 19:23:16 2008 +0800
@@ -436,6 +436,12 @@ acpi_parse_one_rmrr(struct acpi_dmar_ent
     struct acpi_rmrr_unit *rmrru;
     int ret = 0;
 
+    if ( rmrr->base_address >= rmrr->end_address )
+    {
+        dprintk(XENLOG_ERR VTDPREFIX, "RMRR is incorrect.\n");
+        return -EFAULT;
+    }
+
     rmrru = xmalloc(struct acpi_rmrr_unit);
     if ( !rmrru )
         return -ENOMEM;