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[Xen-changelog] [xen-3.2-testing] x86: Foreign mappings of HVM-guest pages should not affect type count,



# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1204735773 0
# Node ID 28e0d4a37bb43079e5db0095a0eed70fc7fa8c13
# Parent  02c4362349d85afe2d1c17628629597dfca50980
x86: Foreign mappings of HVM-guest pages should not affect type count,
even when the mapping is made via a grant reference.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
xen-unstable changeset:   17110:cb3e47897b85b34de1b2b3bee5812318618972a2
xen-unstable date:        Mon Feb 25 11:24:06 2008 +0000
---
 xen/common/grant_table.c              |   24 +++++++++++++++---------
 xen/include/asm-ia64/grant_table.h    |    6 ++++--
 xen/include/asm-powerpc/grant_table.h |   11 ++++-------
 xen/include/asm-x86/grant_table.h     |   14 ++++++--------
 4 files changed, 29 insertions(+), 26 deletions(-)

diff -r 02c4362349d8 -r 28e0d4a37bb4 xen/common/grant_table.c
--- a/xen/common/grant_table.c  Wed Mar 05 16:41:50 2008 +0000
+++ b/xen/common/grant_table.c  Wed Mar 05 16:49:33 2008 +0000
@@ -350,10 +350,10 @@ __gnttab_map_grant_ref(
     else
     {
         if ( unlikely(!mfn_valid(frame)) ||
-             unlikely(!((op->flags & GNTMAP_readonly) ?
-                        get_page(mfn_to_page(frame), rd) :
+             unlikely(!(gnttab_host_mapping_get_page_type(op, ld, rd) ?
                         get_page_and_type(mfn_to_page(frame), rd,
-                                          PGT_writable_page))) )
+                                          PGT_writable_page) :
+                        get_page(mfn_to_page(frame), rd))) )
         {
             if ( !rd->is_dying )
                 gdprintk(XENLOG_WARNING, "Could not pin grant frame %lx\n",
@@ -367,7 +367,7 @@ __gnttab_map_grant_ref(
             rc = create_grant_host_mapping(op->host_addr, frame, op->flags, 0);
             if ( rc != GNTST_okay )
             {
-                if ( !(op->flags & GNTMAP_readonly) )
+                if ( gnttab_host_mapping_get_page_type(op, ld, rd) )
                     put_page_type(mfn_to_page(frame));
                 put_page(mfn_to_page(frame));
                 goto undo_out;
@@ -604,7 +604,7 @@ __gnttab_unmap_common_complete(struct gn
 
         if ( !is_iomem_page(op->frame) ) 
         {
-            if ( !(op->flags & GNTMAP_readonly) )
+            if ( gnttab_host_mapping_get_page_type(op, ld, rd) )
                 put_page_type(mfn_to_page(op->frame));
             put_page(mfn_to_page(op->frame));
         }
@@ -1660,8 +1660,9 @@ gnttab_release_mappings(
             {
                 BUG_ON(!(act->pin & GNTPIN_hstr_mask));
                 act->pin -= GNTPIN_hstr_inc;
-                if ( !is_iomem_page(act->frame) )
-                    gnttab_release_put_page(mfn_to_page(act->frame));
+                if ( gnttab_release_host_mappings &&
+                     !is_iomem_page(act->frame) )
+                    put_page(mfn_to_page(act->frame));
             }
         }
         else
@@ -1678,8 +1679,13 @@ gnttab_release_mappings(
             {
                 BUG_ON(!(act->pin & GNTPIN_hstw_mask));
                 act->pin -= GNTPIN_hstw_inc;
-                if ( !is_iomem_page(act->frame) )
-                    gnttab_release_put_page_and_type(mfn_to_page(act->frame));
+                if ( gnttab_release_host_mappings &&
+                     !is_iomem_page(act->frame) )
+                {
+                    if ( gnttab_host_mapping_get_page_type(map, d, rd) )
+                        put_page_type(mfn_to_page(act->frame));
+                    put_page(mfn_to_page(act->frame));
+                }
             }
 
             if ( (act->pin & (GNTPIN_devw_mask|GNTPIN_hstw_mask)) == 0 )
diff -r 02c4362349d8 -r 28e0d4a37bb4 xen/include/asm-ia64/grant_table.h
--- a/xen/include/asm-ia64/grant_table.h        Wed Mar 05 16:41:50 2008 +0000
+++ b/xen/include/asm-ia64/grant_table.h        Wed Mar 05 16:49:33 2008 +0000
@@ -65,8 +65,10 @@ static inline void gnttab_clear_flag(uns
        clear_bit(nr, addr);
 }
 
-#define gnttab_release_put_page(page)           put_page((page))
-#define gnttab_release_put_page_and_type(page)  put_page_and_type((page))
+#define gnttab_host_mapping_get_page_type(op, ld, rd)   \
+    (!((op)->flags & GNTMAP_readonly))
+
+#define gnttab_release_host_mappings 1
 
 static inline int replace_grant_supported(void)
 {
diff -r 02c4362349d8 -r 28e0d4a37bb4 xen/include/asm-powerpc/grant_table.h
--- a/xen/include/asm-powerpc/grant_table.h     Wed Mar 05 16:41:50 2008 +0000
+++ b/xen/include/asm-powerpc/grant_table.h     Wed Mar 05 16:49:33 2008 +0000
@@ -76,17 +76,14 @@ static inline uint cpu_foreign_map_order
     return 34 - PAGE_SHIFT;
 }
 
-#if 0
+#define gnttab_host_mapping_get_page_type(op, ld, rd)   \
+    (!((op)->flags & GNTMAP_readonly))
+
 /*
  * without put_page()/put_page_and_type() page might be leaked.
  * with put_page()/put_page_and_type() freed page might be accessed.
  */
-#define gnttab_release_put_page(page)           put_page((page))
-#define gnttab_release_put_page_and_type(page)  put_page_and_type((page))
-#else
-#define gnttab_release_put_page(page)           do { } while (0)
-#define gnttab_release_put_page_and_type(page)  do { } while (0)
-#endif
+#define gnttab_release_host_mappings 0
 
 static inline int replace_grant_supported(void)
 {
diff -r 02c4362349d8 -r 28e0d4a37bb4 xen/include/asm-x86/grant_table.h
--- a/xen/include/asm-x86/grant_table.h Wed Mar 05 16:41:50 2008 +0000
+++ b/xen/include/asm-x86/grant_table.h Wed Mar 05 16:49:33 2008 +0000
@@ -38,15 +38,13 @@ static inline void gnttab_clear_flag(uns
     clear_bit(nr, addr);
 }
 
-#define gnttab_release_put_page(page)                           \
-    do {                                                        \
-        /* Done implicitly when page tables are destroyed. */   \
-    } while (0)
+/* Foreign mappings of HHVM-guest pages do not modify the type count. */
+#define gnttab_host_mapping_get_page_type(op, ld, rd)   \
+    (!((op)->flags & GNTMAP_readonly) &&                \
+     (((ld) == (rd)) || !paging_mode_external(rd)))
 
-#define gnttab_release_put_page_and_type(page)                  \
-    do {                                                        \
-        /* Done implicitly when page tables are destroyed. */   \
-    } while (0)
+/* Done implicitly when page tables are destroyed. */
+#define gnttab_release_host_mappings 0
 
 static inline int replace_grant_supported(void)
 {

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