x86/paravirt: add pte_flags to just get pte flags

Add pte_flags() to extract the flags from a pte.  This is a special
case of pte_val() which is only guaranteed to return the pte's flags
correctly; the page number may be corrupted or missing.

The intent is to allow paravirt implementations to return pte flags
without having to do any translation of the page number (most notably,
Xen).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 0f13b945e240..5ea37a48eecb 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -239,6 +239,7 @@ struct pv_mmu_ops {
                                  unsigned long addr, pte_t *ptep);
 
         pteval_t (*pte_val)(pte_t);
+        pteval_t (*pte_flags)(pte_t);
         pte_t (*make_pte)(pteval_t pte);
 
         pgdval_t (*pgd_val)(pgd_t);
@@ -996,6 +997,20 @@ static inline pteval_t pte_val(pte_t pte)
         return ret;
 }
 
+static inline pteval_t pte_flags(pte_t pte)
+{
+        pteval_t ret;
+
+        if (sizeof(pteval_t) > sizeof(long))
+                ret = PVOP_CALL2(pteval_t, pv_mmu_ops.pte_flags,
+                                 pte.pte, (u64)pte.pte >> 32);
+        else
+                ret = PVOP_CALL1(pteval_t, pv_mmu_ops.pte_flags,
+                                 pte.pte);
+
+        return ret;
+}
+
 static inline pgd_t __pgd(pgdval_t val)
 {
         pgdval_t ret;