[Xen-devel] [PATCH v4 13/18] x86/mem_sharing: Skip xen heap pages in memshr nominate

[Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>]

Trying to share these would fail anyway, better to skip them early.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
---
 xen/arch/x86/mm/mem_sharing.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index b8a9228ecf..baa3e35ded 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -852,6 +852,11 @@ static int nominate_page(struct domain *d, gfn_t gfn,
     if ( !p2m_is_sharable(p2mt) )
         goto out;
 
+    /* Skip xen heap pages */
+    page = mfn_to_page(mfn);
+    if ( !page || is_xen_heap_page(page) )
+        goto out;
+
     /* Check if there are mem_access/remapped altp2m entries for this page */
     if ( altp2m_active(d) )
     {
@@ -882,7 +887,6 @@ static int nominate_page(struct domain *d, gfn_t gfn,
     }
 
     /* Try to convert the mfn to the sharable type */
-    page = mfn_to_page(mfn);
     ret = page_make_sharable(d, page, expected_refcnt);
     if ( ret )
         goto out;
-- 
2.20.1


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