[Xen-changelog] [xen stable-4.7] x86: check paging mode earlier in xenmem_add_to_physmap_one()

[patchbot@xxxxxxx]

commit f2d19fbf5f8b4be973d5d0a67350aed1d977e64e
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Dec 20 16:21:03 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Dec 20 16:21:03 2017 +0100

    x86: check paging mode earlier in xenmem_add_to_physmap_one()
    
    There's no point in deferring this until after some initial processing,
    and it's actively wrong for the XENMAPSPACE_gmfn_foreign handling to not
    have such a check at all.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: f38f3dccf1e1a8aabcf57364326fc8f44cddc41a
    master date: 2017-11-28 13:14:43 +0100
---
 xen/arch/x86/mm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d63fcf6..ada12c0 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5022,6 +5022,9 @@ int xenmem_add_to_physmap_one(
     int rc = 0;
     p2m_type_t p2mt;
 
+    if ( !paging_mode_translate(d) )
+        return -EACCES;
+
     switch ( space )
     {
         case XENMAPSPACE_shared_info:
@@ -5078,7 +5081,7 @@ int xenmem_add_to_physmap_one(
             break;
     }
 
-    if ( !paging_mode_translate(d) || (mfn == 0) )
+    if ( mfn == 0 )
     {
         if ( page )
             put_page(page);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.7

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