[Xen-changelog] [xen master] x86: prevent PVH Dom0 from having pages with more than one ref

[patchbot@xxxxxxx]

commit 86104258d36a2d3b0c92aabd2147c731b792f501
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Wed Jun 18 15:52:25 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jun 18 15:52:25 2014 +0200

    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@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/domain_build.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index ba42fc9..d4473c1 100644
--- 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();

--
generated by git-patchbot for /home/xen/git/xen.git#master

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