diff -uNrp linux-3.9.11-200.fc18.x86_64/arch/x86/include/asm/pgtable.h linux-3.9.11-200.PAT.fc18.x86_64/arch/x86/include/asm/pgtable.h
--- linux-3.9.11-200.fc18.x86_64/arch/x86/include/asm/pgtable.h	2013-08-13 22:35:49.372205382 +0200
+++ linux-3.9.11-200.fc18.x86_64/arch/x86/include/asm/pgtable.h	2013-08-13 22:58:23.212956533 +0200
@@ -353,6 +353,11 @@ static inline pgprot_t pgprot_modify(pgp
 	return __pgprot(preservebits | addbits);
 }
 
+static inline pgprot_t pte_attrs(pte_t pte)
+{
+	return __pgprot(pte_val(pte) & PTE_FLAGS_MASK);
+}
+
 #define pte_pgprot(x) __pgprot(pte_flags(x) & PTE_FLAGS_MASK)
 
 #define canon_pgprot(p) __pgprot(massage_pgprot(p))
diff -uNrp linux-3.9.11-200.fc18.x86_64/arch/x86/mm/pageattr.c linux-3.9.11-200.PAT.fc18.x86_64/arch/x86/mm/pageattr.c
--- linux-3.9.11-200.fc18.x86_64/arch/x86/mm/pageattr.c	2013-08-13 22:35:49.377206198 +0200
+++ linux-3.9.11-200.fc18.x86_64/arch/x86/mm/pageattr.c	2013-08-13 22:58:23.213956696 +0200
@@ -708,7 +708,7 @@ repeat:
 
 	if (level == PG_LEVEL_4K) {
 		pte_t new_pte;
-		pgprot_t new_prot = pte_pgprot(old_pte);
+		pgprot_t new_prot = pte_attrs(old_pte);
 		unsigned long pfn = pte_pfn(old_pte);
 
 		pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
diff -uNrp linux-3.9.11-200.fc18.x86_64/arch/x86/xen/enlighten.c linux-3.9.11-200.PAT.fc18.x86_64/arch/x86/xen/enlighten.c
--- linux-3.9.11-200.fc18.x86_64/arch/x86/xen/enlighten.c	2013-08-13 22:35:49.404210605 +0200
+++ linux-3.9.11-200.fc18.x86_64/arch/x86/xen/enlighten.c	2013-08-13 22:52:28.505074079 +0200
@@ -67,7 +67,6 @@
 #include <asm/hypervisor.h>
 #include <asm/mwait.h>
 #include <asm/pci_x86.h>
-#include <asm/pat.h>
 
 #ifdef CONFIG_ACPI
 #include <linux/acpi.h>
@@ -1371,9 +1370,7 @@ asmlinkage void __init xen_start_kernel(
 
 	/* Prevent unwanted bits from being set in PTEs. */
 	__supported_pte_mask &= ~_PAGE_GLOBAL;
-#if 0
 	if (!xen_initial_domain())
-#endif
 		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
 
 	__supported_pte_mask |= _PAGE_IOMAP;
@@ -1433,14 +1430,7 @@ asmlinkage void __init xen_start_kernel(
 	 */
 	acpi_numa = -1;
 #endif
-#ifdef CONFIG_X86_PAT
-	/*
-	 * For right now disable the PAT. We should remove this once
-	 * git commit 8eaffa67b43e99ae581622c5133e20b0f48bcef1
-	 * (xen/pat: Disable PAT support for now) is reverted.
-	 */
-	pat_enabled = 0;
-#endif
+
 	/* Don't do the full vcpu_info placement stuff until we have a
 	   possible map and a non-dummy shared_info. */
 	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
diff -uNrp linux-3.9.11-200.fc18.x86_64/arch/x86/xen/mmu.c linux-3.9.11-200.PAT.fc18.x86_64/arch/x86/xen/mmu.c
--- linux-3.9.11-200.fc18.x86_64/arch/x86/xen/mmu.c	2013-08-13 22:35:49.404210605 +0200
+++ linux-3.9.11-200.fc18.x86_64/arch/x86/xen/mmu.c	2013-08-13 22:47:19.885598037 +0200
@@ -434,13 +434,13 @@ static pteval_t iomap_pte(pteval_t val)
 static 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
+
 	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
 		return pteval;
 
@@ -482,7 +482,7 @@ void xen_set_pat(u64 pat)
 static pte_t xen_make_pte(pteval_t pte)
 {
 	phys_addr_t addr = (pte & PTE_PFN_MASK);
-#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
@@ -495,7 +495,7 @@ static pte_t xen_make_pte(pteval_t pte)
 		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
 			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
 	}
-#endif
+
 	/*
 	 * Unprivileged domains are allowed to do IOMAPpings for
 	 * PCI passthrough, but not map ISA space.  The ISA