p2m/ept: pass correct level to atomic_write_ept_entry in ept_invalidate_emt

The level passed to ept_invalidate_emt corresponds to the EPT entry
passed as the mfn parameter, which is a pointer to an EPT page table,
hence the entries in that page table will have one level less than the
parent.

Fix the call to atomic_write_ept_entry to pass the correct level, ie:
one level less than the parent.

Fixes: 50fe6e7370 ('pvh dom0: add and remove foreign pages')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>.
master commit: b806c91275
master date: 2019-08-28 16:57:36 +0200

xen/arch/x86/mm/p2m-ept.c

@@ -349,7 +349,7 @@ static int ept_next_level(struct p2m_domain *p2m, bool_t read_only,
  * also for their subtrees needing P2M type re-calculation.
  */
 static bool_t ept_invalidate_emt(struct p2m_domain *p2m, mfn_t mfn,
-                                 bool_t recalc, int level)
+                                 bool_t recalc, unsigned int parent_level)
 {
     int rc;
     ept_entry_t *epte = map_domain_page(mfn);
@@ -367,7 +367,7 @@ static bool_t ept_invalidate_emt(struct p2m_domain *p2m, mfn_t mfn,
         e.emt = MTRR_NUM_TYPES;
         if ( recalc )
             e.recalc = 1;
-        rc = atomic_write_ept_entry(p2m, &epte[i], e, level);
+        rc = atomic_write_ept_entry(p2m, &epte[i], e, parent_level - 1);
         ASSERT(rc == 0);
         changed = 1;
     }