Add initial code for disabling PV pagetables

* xen/configfrag.ac (--disable-pv-pagetables): Add option.
* i386/xen/xen_boothdr.S (XEN_ELFNOTE_FEATURES) [!MACH_PV_PAGETABLES]: Add
writable_page_tables.
* i386/i386/gdt.c: Turn appropriate MACH_XEN/MACH_HYP tests into
MACH_PV_PAGETABLES tests.
* i386/i386/i386asm.sym: Likewise
* i386/i386/ldt.c: Likewise
* i386/i386/locore.S: Likewise
* i386/i386/proc_reg.h: Likewise
* i386/i386/user_ldt.c: Likewise
* i386/i386/vm_param.h: Likewise
* i386/i386/xen.h: Likewise
* i386/i386at/model_dep.c: Likewise
* i386/intel/pmap.h: Likewise
* include/mach/xen.h: Likewise
* xen/console.c: Likewise
* xen/store.c: Likewise
* i386/intel/pmap.c: Likewise. Define pmap_map_mfn as TODO stub.

16 files changed, 144 insertions, 98 deletions

diff --git a/i386/i386/gdt.c b/i386/i386/gdt.c
index b686faaf..c3a9a7c1 100644
--- a/i386/i386/gdt.c
+++ b/i386/i386/gdt.c
@@ -101,7 +101,7 @@ gdt_init()
 		     "movw	%w1,%%es\n"
 		     "movw	%w1,%%ss\n"
 		     : : "i" (KERNEL_CS), "r" (KERNEL_DS), "r" (0));
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 #if VM_MIN_KERNEL_ADDRESS != LINEAR_MIN_KERNEL_ADDRESS
 	/* things now get shifted */
 #ifdef	MACH_PSEUDO_PHYS
@@ -109,6 +109,6 @@ gdt_init()
 #endif	/* MACH_PSEUDO_PHYS */
 	la_shift += LINEAR_MIN_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS;
 #endif
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 }
 
diff --git a/i386/i386/i386asm.sym b/i386/i386/i386asm.sym
index 96f5761c..dd1a2edf 100644
--- a/i386/i386/i386asm.sym
+++ b/i386/i386/i386asm.sym
@@ -151,5 +151,7 @@ offset	shared_info		si	vcpu_info[0].evtchn_upcall_pending	CPU_PENDING
 offset	shared_info		si	vcpu_info[0].evtchn_pending_sel	CPU_PENDING_SEL
 offset	shared_info		si	evtchn_pending	PENDING
 offset	shared_info		si	evtchn_mask	EVTMASK
+#ifdef	MACH_PV_PAGETABLES
 offset	shared_info		si	vcpu_info[0].arch.cr2	CR2
+#endif	/* MACH_PV_PAGETABLES */
 #endif	/* MACH_XEN */
diff --git a/i386/i386/ldt.c b/i386/i386/ldt.c
index 58af94b2..43b9efb5 100644
--- a/i386/i386/ldt.c
+++ b/i386/i386/ldt.c
@@ -49,7 +49,9 @@ void
 ldt_init()
 {
 #ifdef	MACH_PV_DESCRIPTORS
+#ifdef	MACH_PV_PAGETABLES
 	pmap_set_page_readwrite(ldt);
+#endif	/* MACH_PV_PAGETABLES */
 #else	/* MACH_PV_DESCRIPTORS */
 	/* Initialize the master LDT descriptor in the GDT.  */
 	fill_gdt_descriptor(KERNEL_LDT,
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index 0e1462cb..d24e1724 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -432,11 +432,11 @@ ENTRY(t_debug)
 ENTRY(t_page_fault)
 	pushl	$(T_PAGE_FAULT)		/* mark a page fault trap */
 	pusha				/* save the general registers */
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	movl	%ss:hyp_shared_info+CR2,%eax
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 	movl	%cr2,%eax		/* get the faulting address */
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 	movl	%eax,R_CR2-R_EDI(%esp)	/* save in esp save slot */
 	jmp	trap_push_segs		/* continue fault */
 
diff --git a/i386/i386/proc_reg.h b/i386/i386/proc_reg.h
index ca493398..c02b2544 100644
--- a/i386/i386/proc_reg.h
+++ b/i386/i386/proc_reg.h
@@ -124,7 +124,7 @@ set_eflags(unsigned long eflags)
 	_temp__; \
     })
 
-#ifdef	MACH_HYP
+#ifdef	MACH_PV_PAGETABLES
 extern unsigned long cr3;
 #define get_cr3() (cr3)
 #define	set_cr3(value) \
@@ -133,7 +133,7 @@ extern unsigned long cr3;
 	if (!hyp_set_cr3(value)) \
 		panic("set_cr3"); \
     })
-#else	/* MACH_HYP */
+#else	/* MACH_PV_PAGETABLES */
 #define	get_cr3() \
     ({ \
 	register unsigned long _temp__; \
@@ -146,11 +146,11 @@ extern unsigned long cr3;
 	register unsigned long _temp__ = (value); \
 	asm volatile("mov %0, %%cr3" : : "r" (_temp__) : "memory"); \
      })
-#endif	/* MACH_HYP */
+#endif	/* MACH_PV_PAGETABLES */
 
 #define flush_tlb() set_cr3(get_cr3())
 
-#ifndef	MACH_HYP
+#ifndef	MACH_PV_PAGETABLES
 #define invlpg(addr) \
     ({ \
 	asm volatile("invlpg (%0)" : : "r" (addr)); \
@@ -178,7 +178,7 @@ extern unsigned long cr3;
 		: "+r" (var) : "r" (end), \
 		  "q" (LINEAR_DS), "q" (KERNEL_DS), "i" (PAGE_SIZE)); \
     })
-#endif	/* MACH_HYP */
+#endif	/* MACH_PV_PAGETABLES */
 
 #define	get_cr4() \
     ({ \
diff --git a/i386/i386/user_ldt.c b/i386/i386/user_ldt.c
index 70ef7cbb..74c10a4c 100644
--- a/i386/i386/user_ldt.c
+++ b/i386/i386/user_ldt.c
@@ -275,8 +275,10 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline)
 #ifdef	MACH_PV_DESCRIPTORS
 	{
 	    int i;
+#ifdef	MACH_PV_PAGETABLES
 	    for (i=0; i<(new_ldt->desc.limit_low + 1)/sizeof(struct real_descriptor); i+=PAGE_SIZE/sizeof(struct real_descriptor))
 		pmap_set_page_readwrite(&new_ldt->ldt[i]);
+#endif	/* MACH_PV_PAGETABLES*/
 	    kfree(new_ldt->alloc, new_ldt->desc.limit_low + 1
 		+ PAGE_SIZE + offsetof(struct user_ldt, ldt));
 	}
@@ -419,8 +421,10 @@ user_ldt_free(user_ldt)
 {
 #ifdef	MACH_PV_DESCRIPTORS
 	int i;
+#ifdef	MACH_PV_PAGETABLES
 	for (i=0; i<(user_ldt->desc.limit_low + 1)/sizeof(struct real_descriptor); i+=PAGE_SIZE/sizeof(struct real_descriptor))
 		pmap_set_page_readwrite(&user_ldt->ldt[i]);
+#endif	/* MACH_PV_PAGETABLES */
 	kfree(user_ldt->alloc, user_ldt->desc.limit_low + 1
 		+ PAGE_SIZE + offsetof(struct user_ldt, ldt));
 #else	/* MACH_PV_DESCRIPTORS */
diff --git a/i386/i386/vm_param.h b/i386/i386/vm_param.h
index ada35638..df857f83 100644
--- a/i386/i386/vm_param.h
+++ b/i386/i386/vm_param.h
@@ -66,14 +66,14 @@
 #define LINEAR_MIN_KERNEL_ADDRESS	(VM_MAX_ADDRESS)
 #define LINEAR_MAX_KERNEL_ADDRESS	(0xffffffffUL)
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 /* need room for mmu updates (2*8bytes) */
 #define KERNEL_STACK_SIZE	(4*I386_PGBYTES)
 #define INTSTACK_SIZE		(4*I386_PGBYTES)
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 #define KERNEL_STACK_SIZE	(1*I386_PGBYTES)
 #define INTSTACK_SIZE		(1*I386_PGBYTES)
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 						/* interrupt stack size */
 
 /*
diff --git a/i386/i386/xen.h b/i386/i386/xen.h
index ba47eb41..5bdaf0b8 100644
--- a/i386/i386/xen.h
+++ b/i386/i386/xen.h
@@ -152,6 +152,7 @@ MACH_INLINE type hyp_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type
 
 _hypcall1(long, set_trap_table, vm_offset_t /* struct trap_info * */, traps);
 
+#ifdef MACH_PV_PAGETABLES
 _hypcall4(int, mmu_update, vm_offset_t /* struct mmu_update * */, req, int, count, vm_offset_t /* int * */, success_count, domid_t, domid)
 MACH_INLINE int hyp_mmu_update_pte(pt_entry_t pte, pt_entry_t val)
 {
@@ -170,6 +171,7 @@ MACH_INLINE int hyp_mmu_update_pte(pt_entry_t pte, pt_entry_t val)
 #define hyp_mmu_update_la(la, val) hyp_mmu_update_pte( \
 	(kernel_pmap->dirbase[lin2pdenum((vm_offset_t)(la))] & INTEL_PTE_PFN) \
 		+ ptenum((vm_offset_t)(la)) * sizeof(pt_entry_t), val)
+#endif
 
 _hypcall2(long, set_gdt, vm_offset_t /* unsigned long * */, frame_list, unsigned int, entries)
 
@@ -216,6 +218,7 @@ MACH_INLINE void hyp_free_page(unsigned long pfn, void *va)
     /* save mfn */
     unsigned long mfn = pfn_to_mfn(pfn);
 
+#ifdef MACH_PV_PAGETABLES
     /* remove from mappings */
     if (hyp_do_update_va_mapping(kvtolin(va), 0, UVMF_INVLPG|UVMF_ALL))
         panic("couldn't clear page %d at %p\n", pfn, va);
@@ -224,11 +227,13 @@ MACH_INLINE void hyp_free_page(unsigned long pfn, void *va)
     /* drop machine page */
     mfn_list[pfn] = ~0;
 #endif  /* MACH_PSEUDO_PHYS */
+#endif
 
     /* and free from Xen  */
     hyp_free_mfn(mfn);
 }
 
+#ifdef MACH_PV_PAGETABLES
 _hypcall4(int, mmuext_op, vm_offset_t /* struct mmuext_op * */, op, int, count, vm_offset_t /* int * */, success_count, domid_t, domid);
 MACH_INLINE int hyp_mmuext_op_void(unsigned int cmd)
 {
@@ -274,6 +279,7 @@ MACH_INLINE void hyp_invlpg(vm_offset_t lin) {
 	if (n < 1)
 		panic("couldn't invlpg\n");
 }
+#endif
 
 _hypcall2(long, set_timer_op, unsigned long, absolute_lo, unsigned long, absolute_hi);
 #define hyp_do_set_timer_op(absolute_nsec) ({ \
diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
index 37610935..3db03d76 100644
--- a/i386/i386at/model_dep.c
+++ b/i386/i386at/model_dep.c
@@ -402,13 +402,13 @@ i386at_init(void)
 #endif
 #endif
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	for (i = 0; i < PDPNUM; i++)
 		pmap_set_page_readonly_init((void*) kernel_page_dir + i * INTEL_PGBYTES);
 #if PAE
 	pmap_set_page_readonly_init(kernel_pmap->pdpbase);
 #endif	/* PAE */
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 #if PAE
 	set_cr3((unsigned)_kvtophys(kernel_pmap->pdpbase));
 #ifndef	MACH_HYP
@@ -430,9 +430,9 @@ i386at_init(void)
 		set_cr4(get_cr4() | CR4_PGE);
 #endif	/* MACH_HYP */
 	flush_instr_queue();
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	pmap_clear_bootstrap_pagetable((void *)boot_info.pt_base);
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 	/* Interrupt stacks are allocated in physical memory,
 	   while kernel stacks are allocated in kernel virtual memory,
diff --git a/i386/intel/pmap.c b/i386/intel/pmap.c
index e211bf31..0be16096 100644
--- a/i386/intel/pmap.c
+++ b/i386/intel/pmap.c
@@ -327,7 +327,7 @@ lock_data_t	pmap_system_lock;
 
 #define MAX_TBIS_SIZE	32		/* > this -> TBIA */ /* XXX */
 
-#ifdef	MACH_HYP
+#ifdef	MACH_PV_PAGETABLES
 #if 1
 #define INVALIDATE_TLB(pmap, s, e) hyp_mmuext_op_void(MMUEXT_TLB_FLUSH_LOCAL)
 #else
@@ -339,7 +339,7 @@ lock_data_t	pmap_system_lock;
 		hyp_mmuext_op_void(MMUEXT_TLB_FLUSH_LOCAL); \
 } while(0)
 #endif
-#else	/* MACH_HYP */
+#else	/* MACH_PV_PAGETABLES */
 #if 0
 /* It is hard to know when a TLB flush becomes less expensive than a bunch of
  * invlpgs.  But it surely is more expensive than just one invlpg.  */
@@ -358,7 +358,7 @@ lock_data_t	pmap_system_lock;
 	flush_tlb(); \
 }
 #endif
-#endif	/* MACH_HYP */
+#endif	/* MACH_PV_PAGETABLES */
 
 
 #if	NCPUS > 1
@@ -528,10 +528,10 @@ vm_offset_t pmap_map_bd(virt, start, end, prot)
 	register pt_entry_t	template;
 	register pt_entry_t	*pte;
 	int			spl;
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	int n, i = 0;
 	struct mmu_update update[HYP_BATCH_MMU_UPDATES];
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 	template = pa_to_pte(start)
 		| INTEL_PTE_NCACHE|INTEL_PTE_WTHRU
@@ -546,7 +546,7 @@ vm_offset_t pmap_map_bd(virt, start, end, prot)
 		pte = pmap_pte(kernel_pmap, virt);
 		if (pte == PT_ENTRY_NULL)
 			panic("pmap_map_bd: Invalid kernel address\n");
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		update[i].ptr = kv_to_ma(pte);
 		update[i].val = pa_to_ma(template);
 		i++;
@@ -556,20 +556,20 @@ vm_offset_t pmap_map_bd(virt, start, end, prot)
 				panic("couldn't pmap_map_bd\n");
 			i = 0;
 		}
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		WRITE_PTE(pte, template)
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		pte_increment_pa(template);
 		virt += PAGE_SIZE;
 		start += PAGE_SIZE;
 	}
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	if (i > HYP_BATCH_MMU_UPDATES)
 		panic("overflowed array in pmap_map_bd");
 	hyp_mmu_update(kvtolin(&update), i, kvtolin(&n), DOMID_SELF);
 	if (n != i)
 		panic("couldn't pmap_map_bd\n");
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 	PMAP_READ_UNLOCK(pmap, spl);
 	return(virt);
 }
@@ -649,7 +649,7 @@ void pmap_bootstrap()
 			kernel_pmap->dirbase[i] = 0;
 	}
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	/* We don't actually deal with the CR3 register content at all */
 	hyp_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3);
 	/*
@@ -698,7 +698,7 @@ void pmap_bootstrap()
 			}
 		}
 	}
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 	/*
 	 * Allocate and set up the kernel page tables.
@@ -736,24 +736,24 @@ void pmap_bootstrap()
 					WRITE_PTE(pte, 0);
 				}
 				else
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 				if (va == (vm_offset_t) &hyp_shared_info)
 				{
 					*pte = boot_info.shared_info | INTEL_PTE_VALID | INTEL_PTE_WRITE;
 					va += INTEL_PGBYTES;
 				}
 				else
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 				{
 					extern char _start[], etext[];
 
 					if (((va >= (vm_offset_t) _start)
 					    && (va + INTEL_PGBYTES <= (vm_offset_t)etext))
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 					    || (va >= (vm_offset_t) boot_info.pt_base
 					    && (va + INTEL_PGBYTES <=
 					    (vm_offset_t) ptable + INTEL_PGBYTES))
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 					    )
 					{
 						WRITE_PTE(pte, pa_to_pte(_kvtophys(va))
@@ -761,7 +761,7 @@ void pmap_bootstrap()
 					}
 					else
 					{
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 						/* Keep supplementary L1 pages read-only */
 						int i;
 						for (i = 0; i < NSUP_L1; i++)
@@ -771,7 +771,7 @@ void pmap_bootstrap()
 								break;
 							}
 						if (i == NSUP_L1)
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 							WRITE_PTE(pte, pa_to_pte(_kvtophys(va))
 								| INTEL_PTE_VALID | INTEL_PTE_WRITE | global)
 
@@ -784,11 +784,11 @@ void pmap_bootstrap()
 				WRITE_PTE(pte, 0);
 				va += INTEL_PGBYTES;
 			}
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			pmap_set_page_readonly_init(ptable);
 			if (!hyp_mmuext_op_mfn (MMUEXT_PIN_L1_TABLE, kv_to_mfn (ptable)))
 				panic("couldn't pin page %p(%p)\n", ptable, (vm_offset_t) kv_to_ma (ptable));
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		}
 	}
 
@@ -796,7 +796,7 @@ void pmap_bootstrap()
 	   soon after we return from here.  */
 }
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 /* These are only required because of Xen security policies */
 
 /* Set back a page read write */
@@ -889,7 +889,7 @@ void pmap_clear_bootstrap_pagetable(pt_entry_t *base) {
 #endif	/* PAE */
 	hyp_free_page(atop(_kvtophys(base)), base);
 }
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 void pmap_virtual_space(startp, endp)
 	vm_offset_t *startp;
@@ -1046,6 +1046,7 @@ pmap_page_table_page_alloc()
 }
 
 #ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 void pmap_map_mfn(void *_addr, unsigned long mfn) {
 	vm_offset_t addr = (vm_offset_t) _addr;
 	pt_entry_t	*pte, *pdp;
@@ -1067,6 +1068,11 @@ void pmap_map_mfn(void *_addr, unsigned long mfn) {
 	if (!hyp_mmu_update_pte(kv_to_ma(pte), ma | INTEL_PTE_VALID | INTEL_PTE_WRITE))
 		panic("%s:%d could not set pte %p(%p) to %p(%p)\n",__FILE__,__LINE__,pte,(vm_offset_t) kv_to_ma(pte), ma, ma_to_pa(ma));
 }
+#else	/* MACH_PV_PAGETABLES */
+void pmap_map_mfn(void *_addr, unsigned long mfn) {
+	panic("TODO %s:%d\n",__FILE__,__LINE__);
+}
+#endif	/* MACH_PV_PAGETABLES */
 #endif	/* MACH_XEN */
 
 /*
@@ -1136,13 +1142,13 @@ pmap_t pmap_create(size)
 	p->dirbase[lin2pdenum(LINEAR_MIN_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS)] = 0;
 #endif
 #endif
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	{
 		int i;
 		for (i = 0; i < PDPNUM; i++)
 			pmap_set_page_readonly((void*) p->dirbase + i * INTEL_PGBYTES);
 	}
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 #if PAE
 	if (kmem_alloc_wired(kernel_map,
@@ -1154,9 +1160,9 @@ pmap_t pmap_create(size)
 		for (i = 0; i < PDPNUM; i++)
 			WRITE_PTE(&p->pdpbase[i], pa_to_pte(kvtophys((vm_offset_t) p->dirbase + i * INTEL_PGBYTES)) | INTEL_PTE_VALID);
 	}
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	pmap_set_page_readonly(p->pdpbase);
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 #endif	/* PAE */
 
 	p->ref_count = 1;
@@ -1216,29 +1222,29 @@ void pmap_destroy(p)
 		if (m == VM_PAGE_NULL)
 		    panic("pmap_destroy: pte page not in object");
 		vm_page_lock_queues();
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		if (!hyp_mmuext_op_mfn (MMUEXT_UNPIN_TABLE, pa_to_mfn(pa)))
 		    panic("pmap_destroy: couldn't unpin page %p(%p)\n", pa, (vm_offset_t) kv_to_ma(pa));
 		pmap_set_page_readwrite((void*) phystokv(pa));
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		vm_page_free(m);
 		inuse_ptepages_count--;
 		vm_page_unlock_queues();
 		vm_object_unlock(pmap_object);
 	    }
 	}
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	{
 		int i;
 		for (i = 0; i < PDPNUM; i++)
 			pmap_set_page_readwrite((void*) p->dirbase + i * INTEL_PGBYTES);
 	}
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 	kmem_free(kernel_map, (vm_offset_t)p->dirbase, PDPNUM * INTEL_PGBYTES);
 #if PAE
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	pmap_set_page_readwrite(p->pdpbase);
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 	kmem_free(kernel_map, (vm_offset_t)p->pdpbase, INTEL_PGBYTES);
 #endif	/* PAE */
 	kmem_cache_free(&pmap_cache, (vm_offset_t) p);
@@ -1284,10 +1290,10 @@ void pmap_remove_range(pmap, va, spte, epte)
 	int			num_removed, num_unwired;
 	int			pai;
 	vm_offset_t		pa;
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	int n, ii = 0;
 	struct mmu_update update[HYP_BATCH_MMU_UPDATES];
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 #if	DEBUG_PTE_PAGE
 	if (pmap != kernel_pmap)
@@ -1316,7 +1322,7 @@ void pmap_remove_range(pmap, va, spte, epte)
 		register int	i = ptes_per_vm_page;
 		register pt_entry_t	*lpte = cpte;
 		do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		    update[ii].ptr = kv_to_ma(lpte);
 		    update[ii].val = 0;
 		    ii++;
@@ -1326,9 +1332,9 @@ void pmap_remove_range(pmap, va, spte, epte)
 				panic("couldn't pmap_remove_range\n");
 			ii = 0;
 		    }
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		    *lpte = 0;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		    lpte++;
 		} while (--i > 0);
 		continue;
@@ -1349,7 +1355,7 @@ void pmap_remove_range(pmap, va, spte, epte)
 		do {
 		    pmap_phys_attributes[pai] |=
 			*lpte & (PHYS_MODIFIED|PHYS_REFERENCED);
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		    update[ii].ptr = kv_to_ma(lpte);
 		    update[ii].val = 0;
 		    ii++;
@@ -1359,9 +1365,9 @@ void pmap_remove_range(pmap, va, spte, epte)
 				panic("couldn't pmap_remove_range\n");
 			ii = 0;
 		    }
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		    *lpte = 0;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		    lpte++;
 		} while (--i > 0);
 	    }
@@ -1407,13 +1413,13 @@ void pmap_remove_range(pmap, va, spte, epte)
 	    }
 	}
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 	if (ii > HYP_BATCH_MMU_UPDATES)
 		panic("overflowed array in pmap_remove_range");
 	hyp_mmu_update(kvtolin(&update), ii, kvtolin(&n), DOMID_SELF);
 	if (n != ii)
 		panic("couldn't pmap_remove_range\n");
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 	/*
 	 *	Update the counts
@@ -1559,12 +1565,12 @@ void pmap_page_protect(phys, prot)
 			do {
 			    pmap_phys_attributes[pai] |=
 				*pte & (PHYS_MODIFIED|PHYS_REFERENCED);
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			    if (!hyp_mmu_update_pte(kv_to_ma(pte++), 0))
 			    	panic("%s:%d could not clear pte %p\n",__FILE__,__LINE__,pte-1);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 			    *pte++ = 0;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 			} while (--i > 0);
 		    }
 
@@ -1594,12 +1600,12 @@ void pmap_page_protect(phys, prot)
 		    register int i = ptes_per_vm_page;
 
 		    do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			if (!hyp_mmu_update_pte(kv_to_ma(pte), *pte & ~INTEL_PTE_WRITE))
 			    	panic("%s:%d could not disable write on pte %p\n",__FILE__,__LINE__,pte);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 			*pte &= ~INTEL_PTE_WRITE;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 			pte++;
 		    } while (--i > 0);
 
@@ -1688,14 +1694,14 @@ void pmap_protect(map, s, e, prot)
 		spte = &spte[ptenum(s)];
 		epte = &spte[intel_btop(l-s)];
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		int n, i = 0;
 		struct mmu_update update[HYP_BATCH_MMU_UPDATES];
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 		while (spte < epte) {
 		    if (*spte & INTEL_PTE_VALID) {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			update[i].ptr = kv_to_ma(spte);
 			update[i].val = *spte & ~INTEL_PTE_WRITE;
 			i++;
@@ -1705,19 +1711,19 @@ void pmap_protect(map, s, e, prot)
 				    panic("couldn't pmap_protect\n");
 			    i = 0;
 			}
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 			*spte &= ~INTEL_PTE_WRITE;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		    }
 		    spte++;
 		}
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		if (i > HYP_BATCH_MMU_UPDATES)
 			panic("overflowed array in pmap_protect");
 		hyp_mmu_update(kvtolin(&update), i, kvtolin(&n), DOMID_SELF);
 		if (n != i)
 			panic("couldn't pmap_protect\n");
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 	    }
 	    s = l;
 	    pde++;
@@ -1854,7 +1860,7 @@ Retry:
 	    /*XX pdp = &pmap->dirbase[pdenum(v) & ~(i-1)];*/
 	    pdp = pmap_pde(pmap, v);
 	    do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		pmap_set_page_readonly((void *) ptp);
 		if (!hyp_mmuext_op_mfn (MMUEXT_PIN_L1_TABLE, kv_to_mfn(ptp)))
 			panic("couldn't pin page %p(%p)\n",ptp,(vm_offset_t) kv_to_ma(ptp));
@@ -1863,11 +1869,11 @@ Retry:
 					      | INTEL_PTE_USER
 					      | INTEL_PTE_WRITE))
 			panic("%s:%d could not set pde %p(%p,%p) to %p(%p,%p) %p\n",__FILE__,__LINE__, pdp, kvtophys((vm_offset_t)pdp), (vm_offset_t) pa_to_ma(kvtophys((vm_offset_t)pdp)), ptp, kvtophys(ptp), (vm_offset_t) pa_to_ma(kvtophys(ptp)), (vm_offset_t) pa_to_pte(kv_to_ma(ptp)));
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		*pdp = pa_to_pte(kvtophys(ptp)) | INTEL_PTE_VALID
 					        | INTEL_PTE_USER
 					        | INTEL_PTE_WRITE;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		pdp++;
 		ptp += INTEL_PGBYTES;
 	    } while (--i > 0);
@@ -1907,12 +1913,12 @@ Retry:
 	    do {
 		if (*pte & INTEL_PTE_MOD)
 		    template |= INTEL_PTE_MOD;
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		if (!hyp_mmu_update_pte(kv_to_ma(pte), pa_to_ma(template)))
 			panic("%s:%d could not set pte %p to %p\n",__FILE__,__LINE__,pte,template);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		WRITE_PTE(pte, template)
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		pte++;
 		pte_increment_pa(template);
 	    } while (--i > 0);
@@ -2017,12 +2023,12 @@ Retry:
 		template |= INTEL_PTE_WIRED;
 	    i = ptes_per_vm_page;
 	    do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		if (!(hyp_mmu_update_pte(kv_to_ma(pte), pa_to_ma(template))))
 			panic("%s:%d could not set pte %p to %p\n",__FILE__,__LINE__,pte,template);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		WRITE_PTE(pte, template)
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		pte++;
 		pte_increment_pa(template);
 	    } while (--i > 0);
@@ -2077,12 +2083,12 @@ void pmap_change_wiring(map, v, wired)
 	    map->stats.wired_count--;
 	    i = ptes_per_vm_page;
 	    do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 		if (!(hyp_mmu_update_pte(kv_to_ma(pte), *pte & ~INTEL_PTE_WIRED)))
 			panic("%s:%d could not wire down pte %p\n",__FILE__,__LINE__,pte);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 		*pte &= ~INTEL_PTE_WIRED;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		pte++;
 	    } while (--i > 0);
 	}
@@ -2213,7 +2219,7 @@ void pmap_collect(p)
 			register int i = ptes_per_vm_page;
 			register pt_entry_t *pdep = pdp;
 			do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			    unsigned long pte = *pdep;
 			    void *ptable = (void*) ptetokv(pte);
 			    if (!(hyp_mmu_update_pte(pa_to_ma(kvtophys((vm_offset_t)pdep++)), 0)))
@@ -2221,9 +2227,9 @@ void pmap_collect(p)
 			    if (!hyp_mmuext_op_mfn (MMUEXT_UNPIN_TABLE, kv_to_mfn(ptable)))
 				panic("couldn't unpin page %p(%p)\n", ptable, (vm_offset_t) pa_to_ma(kvtophys((vm_offset_t)ptable)));
 			    pmap_set_page_readwrite(ptable);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 			    *pdep++ = 0;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 			} while (--i > 0);
 		    }
 
@@ -2440,12 +2446,12 @@ phys_attribute_clear(phys, bits)
 		{
 		    register int	i = ptes_per_vm_page;
 		    do {
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 			if (!(hyp_mmu_update_pte(kv_to_ma(pte), *pte & ~bits)))
 			    panic("%s:%d could not clear bits %lx from pte %p\n",__FILE__,__LINE__,bits,pte);
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 			*pte &= ~bits;
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 		    } while (--i > 0);
 		}
 		PMAP_UPDATE_TLBS(pmap, va, va + PAGE_SIZE);
@@ -2806,12 +2812,12 @@ pmap_unmap_page_zero ()
   if (!pte)
     return;
   assert (pte);
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
   if (!hyp_mmu_update_pte(kv_to_ma(pte), 0))
     printf("couldn't unmap page 0\n");
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
   *pte = 0;
   INVALIDATE_TLB(kernel_pmap, 0, PAGE_SIZE);
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 }
 #endif /* __i386__ */
diff --git a/i386/intel/pmap.h b/i386/intel/pmap.h
index 2692aaef..93293e3d 100644
--- a/i386/intel/pmap.h
+++ b/i386/intel/pmap.h
@@ -132,12 +132,12 @@ typedef unsigned int	pt_entry_t;
 #define INTEL_PTE_NCACHE 	0x00000010
 #define INTEL_PTE_REF		0x00000020
 #define INTEL_PTE_MOD		0x00000040
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 /* Not supported */
 #define INTEL_PTE_GLOBAL	0x00000000
-#else	/* MACH_XEN */
+#else	/* MACH_PV_PAGETABLES */
 #define INTEL_PTE_GLOBAL	0x00000100
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 #define INTEL_PTE_WIRED		0x00000200
 #ifdef PAE
 #define INTEL_PTE_PFN		0x00007ffffffff000ULL
@@ -178,13 +178,13 @@ typedef struct pmap	*pmap_t;
 
 #define PMAP_NULL	((pmap_t) 0)
 
-#ifdef	MACH_XEN
+#ifdef	MACH_PV_PAGETABLES
 extern void pmap_set_page_readwrite(void *addr);
 extern void pmap_set_page_readonly(void *addr);
 extern void pmap_set_page_readonly_init(void *addr);
 extern void pmap_map_mfn(void *addr, unsigned long mfn);
 extern void pmap_clear_bootstrap_pagetable(pt_entry_t *addr);
-#endif	/* MACH_XEN */
+#endif	/* MACH_PV_PAGETABLES */
 
 #if PAE
 #define	set_pmap(pmap)	set_cr3(kvtophys((vm_offset_t)(pmap)->pdpbase))
diff --git a/i386/xen/xen_boothdr.S b/i386/xen/xen_boothdr.S
index 617be519..84666a84 100644
--- a/i386/xen/xen_boothdr.S
+++ b/i386/xen/xen_boothdr.S
@@ -36,6 +36,9 @@
 #else	/* MACH_PSEUDO_PHYS */
 	.ascii	",FEATURES=!auto_translated_physmap"
 #endif
+#ifndef	MACH_PV_PAGETABLES
+	.ascii	"|writable_page_tables"
+#endif	/* MACH_PV_PAGETABLES */
 #ifndef	MACH_PV_DESCRIPTORS
 	.ascii	"|writable_descriptor_tables"
 #endif	/* MACH_PV_DESCRIPTORS */
@@ -76,6 +79,9 @@
 #else /* MACH_PSEUDO_PHYS */
 						"!auto_translated_physmap"
 #endif
+#ifndef	MACH_PV_PAGETABLES
+						"|writable_page_tables"
+#endif	/* MACH_PV_PAGETABLES */
 #ifndef	MACH_PV_DESCRIPTORS
 						"|writable_descriptor_tables"
 #endif	/* MACH_PV_DESCRIPTORS */
diff --git a/include/mach/xen.h b/include/mach/xen.h
index 3bb1d95d..6fc626f2 100644
--- a/include/mach/xen.h
+++ b/include/mach/xen.h
@@ -28,6 +28,7 @@ extern struct start_info boot_info;
 
 extern volatile struct shared_info hyp_shared_info;
 
+#ifdef	MACH_PV_PAGETABLES
 /* Memory translations */
 
 /* pa are physical addresses, from 0 to size of memory */
@@ -77,6 +78,11 @@ extern unsigned long *mfn_list;
 
 #define kv_to_mfn(a)		pa_to_mfn(_kvtophys(a))
 #define kv_to_ma(a)		pa_to_ma(_kvtophys(a))
+#else	/* MACH_PV_PAGETABLES */
+#define mfn_to_pfn(n)		(n)
+#define pfn_to_mfn(n)		(n)
+#endif	/* MACH_PV_PAGETABLES */
+
 #define mfn_to_kv(mfn)		phystokv(ptoa(mfn_to_pfn(mfn)))
 
 #include <machine/xen.h>
diff --git a/xen/configfrag.ac b/xen/configfrag.ac
index b55fc5b6..3745a31f 100644
--- a/xen/configfrag.ac
+++ b/xen/configfrag.ac
@@ -36,6 +36,15 @@ dnl These are experimental
     AM_CONDITIONAL([enable_pseudo_phys], [true])
   [fi]
 
+  AC_ARG_ENABLE([pv-pagetables],
+    AS_HELP_STRING([--disable-pv-pagetables], [Paravirtualized page tables support]))
+  [if [ x"$enable_pv_pagetables" = xno ]; then]
+    AM_CONDITIONAL([enable_pv_pagetables], [false])
+  [else]
+    AC_DEFINE([MACH_PV_PAGETABLES], [], [Enable paravirtualized page tables support])
+    AM_CONDITIONAL([enable_pv_pagetables], [true])
+  [fi]
+
   AC_ARG_ENABLE([pv-descriptors],
     AS_HELP_STRING([--disable-pv-descriptors], [Paravirtualized segment descriptors support]))
   [if [ x"$enable_pv_descriptors" = xno ]; then]
@@ -57,6 +66,7 @@ dnl These are experimental
 [else]
   AM_CONDITIONAL([PLATFORM_xen], [false])
   AM_CONDITIONAL([enable_pseudo_phys], [false])
+  AM_CONDITIONAL([enable_pv_pagetables], [false])
   AM_CONDITIONAL([enable_pv_descriptors], [false])
   AM_CONDITIONAL([enable_ring1], [false])
 [fi]
diff --git a/xen/console.c b/xen/console.c
index cb61d45d..884376ff 100644
--- a/xen/console.c
+++ b/xen/console.c
@@ -232,7 +232,9 @@ int hypcninit(struct consdev *cp)
 	simple_lock_init(&outlock);
 	simple_lock_init(&inlock);
 	console = (void*) mfn_to_kv(boot_info.console_mfn);
+#ifdef	MACH_PV_PAGETABLES
 	pmap_set_page_readwrite(console);
+#endif	/* MACH_PV_PAGETABLES */
 	hyp_evt_handler(boot_info.console_evtchn, hypcnintr, 0, SPL6);
 	return 0;
 }
diff --git a/xen/store.c b/xen/store.c
index 8796bb59..739dc367 100644
--- a/xen/store.c
+++ b/xen/store.c
@@ -329,7 +329,9 @@ void hyp_store_init(void)
 		return;
 	simple_lock_init(&lock);
 	store = (void*) mfn_to_kv(boot_info.store_mfn);
+#ifdef	MACH_PV_PAGETABLES
 	pmap_set_page_readwrite(store);
+#endif	/* MACH_PV_PAGETABLES */
 	/* SPL sched */
 	hyp_evt_handler(boot_info.store_evtchn, hyp_store_handler, 0, SPL7);
 }