[Xen-changelog] Fix the performance issues of 2-level paging HVM guests on the PAE

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID d20a2a971103e4c9cd09d9284707437cd1c28b77
# Parent  79d28e3505c27cdd31e000320da9eb37d4b9f18e
Fix the performance issues of 2-level paging HVM guests on the PAE
Xen. With this, the performance will be basically same as 2-on-2.

Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx>
---
 xen/arch/x86/shadow.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+)

diff -r 79d28e3505c2 -r d20a2a971103 xen/arch/x86/shadow.c
--- a/xen/arch/x86/shadow.c     Mon May 15 07:44:12 2006 +0100
+++ b/xen/arch/x86/shadow.c     Mon May 15 07:46:57 2006 +0100
@@ -347,6 +347,13 @@ alloc_shadow_page(struct domain *d,
         d->arch.shadow_page_count++;
         if ( PGT_l4_page_table == PGT_root_page_table )
             pin = 1;
+#if CONFIG_PAGING_LEVELS == 3 & defined (GUEST_PGENTRY_32)
+        /*
+         * We use PGT_l4_shadow for 2-level paging guests on PAE
+         */
+        if ( d->arch.ops->guest_paging_levels == PAGING_L2 )
+            pin = 1;
+#endif
         break;
 
 #if CONFIG_PAGING_LEVELS >= 4
@@ -2425,6 +2432,17 @@ static void shadow_update_pagetables(str
     /*
      *  arch.shadow_table
      */
+#if CONFIG_PAGING_LEVELS == 3 & defined (GUEST_PGENTRY_32)
+    /*
+     * We use PGT_l4_shadow for 2-level paging guests on PAE
+     */
+    if ( d->arch.ops->guest_paging_levels == PAGING_L2 )
+    { 
+        if ( unlikely(!(smfn = __shadow_status(d, gpfn, PGT_l4_shadow))) )
+            smfn = shadow_l3_table(v, gpfn, gmfn);
+    } 
+    else
+#endif
     if ( unlikely(!(smfn = __shadow_status(d, gpfn, PGT_base_page_table))) ) 
     {
 #if CONFIG_PAGING_LEVELS == 2

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