x86: prevent PVH Dom0 from having pages with more than one ref

On PV guests a reference is taken when a page gets added to the page
tables, which makes pages added to the page tables have two
references, but this is not suitable for PVH that doesn't use the
PVMMU. In the PVH case only one reference has to be taken or else the
page would not be freed when the memory of the domain is decreased.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index ba42fc90e0798ea1b4729718e634bbd86e081c48..d4473c1bf8ef139ee3663707f52678d27f10bf6b 100644 (file)
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -1137,10 +1137,13 @@ int __init construct_dom0(
                                     L1_PROT : COMPAT_L1_PROT));
         l1tab++;
 
-        page = mfn_to_page(mfn);
-        if ( (page->u.inuse.type_info == 0) &&
-             !get_page_and_type(page, d, PGT_writable_page) )
-            BUG();
+        if ( !paging_mode_translate(d) )
+        {
+            page = mfn_to_page(mfn);
+            if ( !page->u.inuse.type_info &&
+                 !get_page_and_type(page, d, PGT_writable_page) )
+                BUG();
+        }
     }
 
     if ( is_pv_32on64_domain(d) )
@@ -1300,7 +1303,7 @@ int __init construct_dom0(
         if ( get_gpfn_from_mfn(mfn) >= count )
         {
             BUG_ON(is_pv_32bit_domain(d));
-            if ( !page->u.inuse.type_info &&
+            if ( !paging_mode_translate(d) && !page->u.inuse.type_info &&
                  !get_page_and_type(page, d, PGT_writable_page) )
                 BUG();