[Xen-devel] [PATCH for-4.9] x86/pagewalk: Fix determination of Protection Key access rights

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

c/s 4c5d78a10 was accidentally buggy when handling Protection Keys.
Protection keys applies to all user translations, not just accesses which
originate from user mode.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

This regression was introducing during the 4.9 timeframe, so really should be
fixed before 4.9 ships.
---
 xen/arch/x86/mm/guest_walk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c
index 32d818e..ba72432 100644
--- a/xen/arch/x86/mm/guest_walk.c
+++ b/xen/arch/x86/mm/guest_walk.c
@@ -408,7 +408,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
      * N.B. In the case that the walk ended with a superpage, the fabricated
      * gw->l1e contains the appropriate leaf pkey.
      */
-    if ( (walk & PFEC_user_mode) && !(walk & PFEC_insn_fetch) &&
+    if ( (ar & _PAGE_USER) && !(walk & PFEC_insn_fetch) &&
          guest_pku_enabled(v) )
     {
         unsigned int pkey = guest_l1e_get_pkey(gw->l1e);
-- 
2.1.4


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