diff -r c33a40b4c22b xen/drivers/passthrough/vtd/intremap.c
--- a/xen/drivers/passthrough/vtd/intremap.c	Mon Jun 30 14:19:09 2008 +0100
+++ b/xen/drivers/passthrough/vtd/intremap.c	Tue Jul 01 13:45:12 2008 +0800
@@ -153,6 +153,7 @@ static void ioapic_rte_to_remap_entry(st
     }
 
     memcpy(iremap_entry, &new_ire, sizeof(struct iremap_entry));
+    iommu_flush_cache_entry(iremap_entry);
     iommu_flush_iec_index(iommu, 0, index);
     invalidate_sync(iommu);
 
@@ -378,6 +379,7 @@ static void msi_msg_to_remap_entry(
     remap_rte->data = 0;
 
     memcpy(iremap_entry, &new_ire, sizeof(struct iremap_entry));
+    iommu_flush_cache_entry(iremap_entry);
     iommu_flush_iec_index(iommu, 0, index);
     invalidate_sync(iommu);