[Xen-devel] [PATCH v5 03/18] x86/p2m: Allow p2m_get_page_from_gfn to return shared entries

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

The owner domain of shared pages is dom_cow, use that for get_page
otherwise the function fails to return the correct page.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 3119269073..fdeb742707 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -594,7 +594,10 @@ struct page_info *p2m_get_page_from_gfn(
     if ( p2m_is_ram(*t) && mfn_valid(mfn) )
     {
         page = mfn_to_page(mfn);
-        if ( !get_page(page, p2m->domain) )
+        if ( !get_page(page, p2m->domain) &&
+             /* Page could be shared */
+             (!dom_cow || !p2m_is_shared(*t) ||
+              !get_page(page, dom_cow)) )
             page = NULL;
     }
     put_gfn(p2m->domain, gfn_x(gfn));
-- 
2.20.1


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