x86/mm: add information about faulted page's presence to npfec structure

This is provided explicitly in SVM and implicitly in VMX (when neither of
the three EPT_EFFECTIVE_* bits is set).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
master commit: 1a966b46a0
master date: 2015-12-21 13:38:53 +0100

xen/arch/x86/hvm/svm/svm.c

@@ -1467,7 +1467,8 @@ static void svm_do_nested_pgfault(struct vcpu *v,
     struct npfec npfec = {
         .read_access = !(pfec & PFEC_insn_fetch),
         .write_access = !!(pfec & PFEC_write_access),
-        .insn_fetch = !!(pfec & PFEC_insn_fetch)
+        .insn_fetch = !!(pfec & PFEC_insn_fetch),
+        .present = !!(pfec & PFEC_page_present),
     };
 
     /* These bits are mutually exclusive */

xen/arch/x86/hvm/vmx/vmx.c

@@ -2627,7 +2627,10 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
         .read_access = !!(qualification & EPT_READ_VIOLATION) ||
                        !!(qualification & EPT_WRITE_VIOLATION),
         .write_access = !!(qualification & EPT_WRITE_VIOLATION),
-        .insn_fetch = !!(qualification & EPT_EXEC_VIOLATION)
+        .insn_fetch = !!(qualification & EPT_EXEC_VIOLATION),
+        .present = !!(qualification & (EPT_EFFECTIVE_READ |
+                                       EPT_EFFECTIVE_WRITE |
+                                       EPT_EFFECTIVE_EXEC))
     };
 
     if ( tb_init_done )

xen/include/xen/mm.h

@@ -159,6 +159,7 @@ struct npfec {
     unsigned int read_access:1;
     unsigned int write_access:1;
     unsigned int insn_fetch:1;
+    unsigned int present:1;
     unsigned int gla_valid:1;
     unsigned int kind:2;  /* npfec_kind_t */
 };