[Xen-devel] [PATCH 6 of 9] x86/mm: Fix balooning+sharing

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

 xen/common/memory.c |  12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)


Never mind that ballooning a shared page makes no sense. We still fix it
because it may be exercised.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r 1c61573d1765 -r 75dec1a0ba2d xen/common/memory.c
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -185,12 +185,14 @@ int guest_remove_page(struct domain *d, 
 #ifdef CONFIG_X86
     /* If gmfn is shared, just drop the guest reference (which may or may not
      * free the page) */
-    if(p2m_is_shared(p2mt))
+    if ( p2m_is_shared(p2mt) )
     {
-        put_page_and_type(page);
-        guest_physmap_remove_page(d, gmfn, mfn, 0);
-        put_gfn(d, gmfn);
-        return 1;
+        /* Unshare the page, bail out on error. We unshare because 
+         * we might be the only one using this shared page, and we
+         * need to trigger proper cleanup. Once done, this is 
+         * like any other page. */
+        if ( mem_sharing_unshare_page(d, gmfn, 0) )
+            return 0;
     }
 
 #endif /* CONFIG_X86 */

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