[Xen-devel] [PATCH 3 of 3] amd iommu: Remove unnecessary map/unmap for l1 page tables

[Wei Wang <wei.wang2@xxxxxxx>]

# HG changeset patch
# User Wei Wang <wei.wang2@xxxxxxx>
# Date 1344872316 -7200
# Node ID 076df9db4c273e9786ea373bda092716015d9403
# Parent  273471c6dedd1e66caab7e4eede72130e4e0c00f
amd iommu: Remove unnecessary map/unmap for l1 page tables

Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>

diff -r 273471c6dedd -r 076df9db4c27 xen/drivers/passthrough/amd/pci_amd_iommu.c
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c       Mon Aug 13 17:38:33 
2012 +0200
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c       Mon Aug 13 17:38:36 
2012 +0200
@@ -394,25 +394,27 @@ static void deallocate_next_page_table(s
     u64 next_table_maddr;
     int index, next_level;
 
+    if ( level <= 1 )
+    {
+        free_amd_iommu_pgtable(pg);
+        return;
+    }
+
     table_vaddr = __map_domain_page(pg);
 
-    if ( level > 1 )
+    for ( index = 0; index < PTE_PER_TABLE_SIZE; index++ )
     {
-        for ( index = 0; index < PTE_PER_TABLE_SIZE; index++ )
+        pde = table_vaddr + (index * IOMMU_PAGE_TABLE_ENTRY_SIZE);
+        next_table_maddr = amd_iommu_get_next_table_from_pte(pde);
+        next_level = iommu_next_level((u32*)pde);
+
+        if ( (next_table_maddr != 0) && (next_level != 0)
+             && iommu_is_pte_present((u32*)pde) )
         {
-            pde = table_vaddr + (index * IOMMU_PAGE_TABLE_ENTRY_SIZE);
-            next_table_maddr = amd_iommu_get_next_table_from_pte(pde);
-
-            next_level = iommu_next_level((u32*)pde);
-
-            if ( (next_table_maddr != 0) && (next_level != 0)
-                && iommu_is_pte_present((u32*)pde) )
-            {
-                /* We do not support skip level yet */
-                ASSERT( next_level == level - 1 );
-                deallocate_next_page_table(
-                    maddr_to_page(next_table_maddr), next_level);
-            }
+            /* We do not support skip levels yet */
+            ASSERT( next_level == level - 1 );
+            deallocate_next_page_table(maddr_to_page(next_table_maddr), 
+                                       next_level);
         }
     }
 


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