[Xen-devel] [PATCH] xen: don't flush the TLB on grant unmap for auto-translated guests

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

For auto-translated guests the p2m code will do the necessary TLB
flushes, so there's no need to perform any TLB flushes in generic
grant table code.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/common/grant_table.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 107b000..a2a857f 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -1099,7 +1099,8 @@ gnttab_unmap_grant_ref(
             guest_handle_add_offset(uop, 1);
         }
 
-        flush_tlb_mask(current->domain->domain_dirty_cpumask);
+        if ( !paging_mode_external(current->domain) )
+            flush_tlb_mask(current->domain->domain_dirty_cpumask);
 
         for ( i = 0; i < partial_done; i++ )
             __gnttab_unmap_common_complete(&(common[i]));
@@ -1114,7 +1115,8 @@ gnttab_unmap_grant_ref(
     return 0;
 
 fault:
-    flush_tlb_mask(current->domain->domain_dirty_cpumask);
+    if ( !paging_mode_external(current->domain) )
+        flush_tlb_mask(current->domain->domain_dirty_cpumask);
 
     for ( i = 0; i < partial_done; i++ )
         __gnttab_unmap_common_complete(&(common[i]));
@@ -1162,7 +1164,8 @@ gnttab_unmap_and_replace(
             guest_handle_add_offset(uop, 1);
         }
         
-        flush_tlb_mask(current->domain->domain_dirty_cpumask);
+        if ( !paging_mode_external(current->domain) )
+            flush_tlb_mask(current->domain->domain_dirty_cpumask);
         
         for ( i = 0; i < partial_done; i++ )
             __gnttab_unmap_common_complete(&(common[i]));
@@ -1177,7 +1180,8 @@ gnttab_unmap_and_replace(
     return 0;
 
 fault:
-    flush_tlb_mask(current->domain->domain_dirty_cpumask);
+    if ( !paging_mode_external(current->domain) )
+        flush_tlb_mask(current->domain->domain_dirty_cpumask);
 
     for ( i = 0; i < partial_done; i++ )
         __gnttab_unmap_common_complete(&(common[i]));
-- 
1.7.7.5 (Apple Git-26)


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