xen: Support Xen pv-domains using PAT

[cascardo/linux.git] / arch / x86 / xen / mmu.c

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a8a1a3d..9855eb8 100644 (file)
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -410,13 +410,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
 __visible pteval_t xen_pte_val(pte_t pte)
 {
        pteval_t pteval = pte.pte;
-#if 0
-       /* If this is a WC pte, convert back from Xen WC to Linux WC */
-       if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
-               WARN_ON(!pat_enabled);
-               pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
-       }
-#endif
+
        return pte_mfn_to_pfn(pteval);
 }
 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
@@ -427,47 +421,8 @@ __visible pgdval_t xen_pgd_val(pgd_t pgd)
 }
 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
 
-/*
- * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
- * are reserved for now, to correspond to the Intel-reserved PAT
- * types.
- *
- * We expect Linux's PAT set as follows:
- *
- * Idx  PTE flags        Linux    Xen    Default
- * 0                     WB       WB     WB
- * 1            PWT      WC       WT     WT
- * 2        PCD          UC-      UC-    UC-
- * 3        PCD PWT      UC       UC     UC
- * 4    PAT              WB       WC     WB
- * 5    PAT     PWT      WC       WP     WT
- * 6    PAT PCD          UC-      rsv    UC-
- * 7    PAT PCD PWT      UC       rsv    UC
- */
-
-void xen_set_pat(u64 pat)
-{
-       /* We expect Linux to use a PAT setting of
-        * UC UC- WC WB (ignoring the PAT flag) */
-       WARN_ON(pat != 0x0007010600070106ull);
-}
-
 __visible pte_t xen_make_pte(pteval_t pte)
 {
-#if 0
-       /* If Linux is trying to set a WC pte, then map to the Xen WC.
-        * If _PAGE_PAT is set, then it probably means it is really
-        * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
-        * things work out OK...
-        *
-        * (We should never see kernel mappings with _PAGE_PSE set,
-        * but we could see hugetlbfs mappings, I think.).
-        */
-       if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
-               if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
-                       pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
-       }
-#endif
        pte = pte_pfn_to_mfn(pte);
 
        return native_make_pte(pte);