1 files changed, 474 insertions, 98 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 4e527e7893a8..aa37469da696 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -44,8 +44,10 @@
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
+#include <asm/fixmap.h>
 #include <asm/mmu_context.h>
 #include <asm/paravirt.h>
+#include <asm/linkage.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -56,15 +58,144 @@
 #include "multicalls.h"
 #include "mmu.h"
 
-xmaddr_t arbitrary_virt_to_machine(unsigned long address)
+/*
+ * Just beyond the highest usermode address.  STACK_TOP_MAX has a
+ * redzone above it, so round it up to a PGD boundary.
+ */
+#define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
+
+
+#define P2M_ENTRIES_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long))
+#define TOP_ENTRIES		(MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
+
+/* Placeholder for holes in the address space */
+static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
+		{ [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
+
+ /* Array of pointers to pages containing p2m entries */
+static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
+		{ [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
+
+/* Arrays of p2m arrays expressed in mfns used for save/restore */
+static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
+
+static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
+	__page_aligned_bss;
+
+static inline unsigned p2m_top_index(unsigned long pfn)
+{
+	BUG_ON(pfn >= MAX_DOMAIN_PAGES);
+	return pfn / P2M_ENTRIES_PER_PAGE;
+}
+
+static inline unsigned p2m_index(unsigned long pfn)
+{
+	return pfn % P2M_ENTRIES_PER_PAGE;
+}
+
+/* Build the parallel p2m_top_mfn structures */
+void xen_setup_mfn_list_list(void)
+{
+	unsigned pfn, idx;
+
+	for(pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
+		unsigned topidx = p2m_top_index(pfn);
+
+		p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
+	}
+
+	for(idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
+		unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
+		p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
+	}
+
+	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+		virt_to_mfn(p2m_top_mfn_list);
+	HYPERVISOR_shared_info->arch.max_pfn = xen_start_info->nr_pages;
+}
+
+/* Set up p2m_top to point to the domain-builder provided p2m pages */
+void __init xen_build_dynamic_phys_to_machine(void)
+{
+	unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
+	unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
+	unsigned pfn;
+
+	for(pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
+		unsigned topidx = p2m_top_index(pfn);
+
+		p2m_top[topidx] = &mfn_list[pfn];
+	}
+}
+
+unsigned long get_phys_to_machine(unsigned long pfn)
+{
+	unsigned topidx, idx;
+
+	if (unlikely(pfn >= MAX_DOMAIN_PAGES))
+		return INVALID_P2M_ENTRY;
+
+	topidx = p2m_top_index(pfn);
+	idx = p2m_index(pfn);
+	return p2m_top[topidx][idx];
+}
+EXPORT_SYMBOL_GPL(get_phys_to_machine);
+
+static void alloc_p2m(unsigned long **pp, unsigned long *mfnp)
+{
+	unsigned long *p;
+	unsigned i;
+
+	p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
+	BUG_ON(p == NULL);
+
+	for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
+		p[i] = INVALID_P2M_ENTRY;
+
+	if (cmpxchg(pp, p2m_missing, p) != p2m_missing)
+		free_page((unsigned long)p);
+	else
+		*mfnp = virt_to_mfn(p);
+}
+
+void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+	unsigned topidx, idx;
+
+	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+		return;
+	}
+
+	if (unlikely(pfn >= MAX_DOMAIN_PAGES)) {
+		BUG_ON(mfn != INVALID_P2M_ENTRY);
+		return;
+	}
+
+	topidx = p2m_top_index(pfn);
+	if (p2m_top[topidx] == p2m_missing) {
+		/* no need to allocate a page to store an invalid entry */
+		if (mfn == INVALID_P2M_ENTRY)
+			return;
+		alloc_p2m(&p2m_top[topidx], &p2m_top_mfn[topidx]);
+	}
+
+	idx = p2m_index(pfn);
+	p2m_top[topidx][idx] = mfn;
+}
+
+xmaddr_t arbitrary_virt_to_machine(void *vaddr)
 {
+	unsigned long address = (unsigned long)vaddr;
 	unsigned int level;
 	pte_t *pte = lookup_address(address, &level);
 	unsigned offset = address & ~PAGE_MASK;
 
 	BUG_ON(pte == NULL);
 
-	return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
+	return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
 }
 
 void make_lowmem_page_readonly(void *vaddr)
@@ -98,59 +229,68 @@ void make_lowmem_page_readwrite(void *vaddr)
 }
 
 
-void xen_set_pmd(pmd_t *ptr, pmd_t val)
+static bool page_pinned(void *ptr)
+{
+	struct page *page = virt_to_page(ptr);
+
+	return PagePinned(page);
+}
+
+static void extend_mmu_update(const struct mmu_update *update)
 {
 	struct multicall_space mcs;
 	struct mmu_update *u;
 
-	preempt_disable();
+	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+	if (mcs.mc != NULL)
+		mcs.mc->args[1]++;
+	else {
+		mcs = __xen_mc_entry(sizeof(*u));
+		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+	}
 
-	mcs = xen_mc_entry(sizeof(*u));
 	u = mcs.args;
-	u->ptr = virt_to_machine(ptr).maddr;
-	u->val = pmd_val_ma(val);
-	MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+	*u = *update;
+}
+
+void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
+{
+	struct mmu_update u;
+
+	preempt_disable();
+
+	xen_mc_batch();
+
+	/* ptr may be ioremapped for 64-bit pagetable setup */
+	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+	u.val = pmd_val_ma(val);
+	extend_mmu_update(&u);
 
 	xen_mc_issue(PARAVIRT_LAZY_MMU);
 
 	preempt_enable();
 }
 
+void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!page_pinned(ptr)) {
+		*ptr = val;
+		return;
+	}
+
+	xen_set_pmd_hyper(ptr, val);
+}
+
 /*
  * Associate a virtual page frame with a given physical page frame
  * and protection flags for that frame.
  */
 void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
 {
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-
-	pgd = swapper_pg_dir + pgd_index(vaddr);
-	if (pgd_none(*pgd)) {
-		BUG();
-		return;
-	}
-	pud = pud_offset(pgd, vaddr);
-	if (pud_none(*pud)) {
-		BUG();
-		return;
-	}
-	pmd = pmd_offset(pud, vaddr);
-	if (pmd_none(*pmd)) {
-		BUG();
-		return;
-	}
-	pte = pte_offset_kernel(pmd, vaddr);
-	/* <mfn,flags> stored as-is, to permit clearing entries */
-	xen_set_pte(pte, mfn_pte(mfn, flags));
-
-	/*
-	 * It's enough to flush this one mapping.
-	 * (PGE mappings get flushed as well)
-	 */
-	__flush_tlb_one(vaddr);
+	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
 }
 
 void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
@@ -179,12 +319,32 @@ out:
 		preempt_enable();
 }
 
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	/* Just return the pte as-is.  We preserve the bits on commit */
+	return *ptep;
+}
+
+void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+				 pte_t *ptep, pte_t pte)
+{
+	struct mmu_update u;
+
+	xen_mc_batch();
+
+	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+	u.val = pte_val_ma(pte);
+	extend_mmu_update(&u);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
 /* Assume pteval_t is equivalent to all the other *val_t types. */
 static pteval_t pte_mfn_to_pfn(pteval_t val)
 {
 	if (val & _PAGE_PRESENT) {
-		unsigned long mfn = (val & PTE_MASK) >> PAGE_SHIFT;
-		pteval_t flags = val & ~PTE_MASK;
+		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+		pteval_t flags = val & PTE_FLAGS_MASK;
 		val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
 	}
 
@@ -194,8 +354,8 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
 static pteval_t pte_pfn_to_mfn(pteval_t val)
 {
 	if (val & _PAGE_PRESENT) {
-		unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
-		pteval_t flags = val & ~PTE_MASK;
+		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+		pteval_t flags = val & PTE_FLAGS_MASK;
 		val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
 	}
 
@@ -229,34 +389,51 @@ pmdval_t xen_pmd_val(pmd_t pmd)
 	return pte_mfn_to_pfn(pmd.pmd);
 }
 
-void xen_set_pud(pud_t *ptr, pud_t val)
+void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 {
-	struct multicall_space mcs;
-	struct mmu_update *u;
+	struct mmu_update u;
 
 	preempt_disable();
 
-	mcs = xen_mc_entry(sizeof(*u));
-	u = mcs.args;
-	u->ptr = virt_to_machine(ptr).maddr;
-	u->val = pud_val_ma(val);
-	MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+	xen_mc_batch();
+
+	/* ptr may be ioremapped for 64-bit pagetable setup */
+	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+	u.val = pud_val_ma(val);
+	extend_mmu_update(&u);
 
 	xen_mc_issue(PARAVIRT_LAZY_MMU);
 
 	preempt_enable();
 }
 
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!page_pinned(ptr)) {
+		*ptr = val;
+		return;
+	}
+
+	xen_set_pud_hyper(ptr, val);
+}
+
 void xen_set_pte(pte_t *ptep, pte_t pte)
 {
+#ifdef CONFIG_X86_PAE
 	ptep->pte_high = pte.pte_high;
 	smp_wmb();
 	ptep->pte_low = pte.pte_low;
+#else
+	*ptep = pte;
+#endif
 }
 
+#ifdef CONFIG_X86_PAE
 void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
 {
-	set_64bit((u64 *)ptep, pte_val_ma(pte));
+	set_64bit((u64 *)ptep, native_pte_val(pte));
 }
 
 void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
@@ -268,8 +445,9 @@ void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 
 void xen_pmd_clear(pmd_t *pmdp)
 {
-	xen_set_pmd(pmdp, __pmd(0));
+	set_pmd(pmdp, __pmd(0));
 }
+#endif	/* CONFIG_X86_PAE */
 
 pmd_t xen_make_pmd(pmdval_t pmd)
 {
@@ -277,78 +455,189 @@ pmd_t xen_make_pmd(pmdval_t pmd)
 	return native_make_pmd(pmd);
 }
 
+#if PAGETABLE_LEVELS == 4
+pudval_t xen_pud_val(pud_t pud)
+{
+	return pte_mfn_to_pfn(pud.pud);
+}
+
+pud_t xen_make_pud(pudval_t pud)
+{
+	pud = pte_pfn_to_mfn(pud);
+
+	return native_make_pud(pud);
+}
+
+pgd_t *xen_get_user_pgd(pgd_t *pgd)
+{
+	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
+	unsigned offset = pgd - pgd_page;
+	pgd_t *user_ptr = NULL;
+
+	if (offset < pgd_index(USER_LIMIT)) {
+		struct page *page = virt_to_page(pgd_page);
+		user_ptr = (pgd_t *)page->private;
+		if (user_ptr)
+			user_ptr += offset;
+	}
+
+	return user_ptr;
+}
+
+static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptr).maddr;
+	u.val = pgd_val_ma(val);
+	extend_mmu_update(&u);
+}
+
 /*
-  (Yet another) pagetable walker.  This one is intended for pinning a
-  pagetable.  This means that it walks a pagetable and calls the
-  callback function on each page it finds making up the page table,
-  at every level.  It walks the entire pagetable, but it only bothers
-  pinning pte pages which are below pte_limit.  In the normal case
-  this will be TASK_SIZE, but at boot we need to pin up to
-  FIXADDR_TOP.  But the important bit is that we don't pin beyond
-  there, because then we start getting into Xen's ptes.
-*/
-static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, enum pt_level),
+ * Raw hypercall-based set_pgd, intended for in early boot before
+ * there's a page structure.  This implies:
+ *  1. The only existing pagetable is the kernel's
+ *  2. It is always pinned
+ *  3. It has no user pagetable attached to it
+ */
+void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+	preempt_disable();
+
+	xen_mc_batch();
+
+	__xen_set_pgd_hyper(ptr, val);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+void xen_set_pgd(pgd_t *ptr, pgd_t val)
+{
+	pgd_t *user_ptr = xen_get_user_pgd(ptr);
+
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!page_pinned(ptr)) {
+		*ptr = val;
+		if (user_ptr) {
+			WARN_ON(page_pinned(user_ptr));
+			*user_ptr = val;
+		}
+		return;
+	}
+
+	/* If it's pinned, then we can at least batch the kernel and
+	   user updates together. */
+	xen_mc_batch();
+
+	__xen_set_pgd_hyper(ptr, val);
+	if (user_ptr)
+		__xen_set_pgd_hyper(user_ptr, val);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+#endif	/* PAGETABLE_LEVELS == 4 */
+
+/*
+ * (Yet another) pagetable walker.  This one is intended for pinning a
+ * pagetable.  This means that it walks a pagetable and calls the
+ * callback function on each page it finds making up the page table,
+ * at every level.  It walks the entire pagetable, but it only bothers
+ * pinning pte pages which are below limit.  In the normal case this
+ * will be STACK_TOP_MAX, but at boot we need to pin up to
+ * FIXADDR_TOP.
+ *
+ * For 32-bit the important bit is that we don't pin beyond there,
+ * because then we start getting into Xen's ptes.
+ *
+ * For 64-bit, we must skip the Xen hole in the middle of the address
+ * space, just after the big x86-64 virtual hole.
+ */
+static int pgd_walk(pgd_t *pgd, int (*func)(struct page *, enum pt_level),
 		    unsigned long limit)
 {
-	pgd_t *pgd = pgd_base;
 	int flush = 0;
-	unsigned long addr = 0;
-	unsigned long pgd_next;
+	unsigned hole_low, hole_high;
+	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
+	unsigned pgdidx, pudidx, pmdidx;
 
-	BUG_ON(limit > FIXADDR_TOP);
+	/* The limit is the last byte to be touched */
+	limit--;
+	BUG_ON(limit >= FIXADDR_TOP);
 
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return 0;
 
-	for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) {
+	/*
+	 * 64-bit has a great big hole in the middle of the address
+	 * space, which contains the Xen mappings.  On 32-bit these
+	 * will end up making a zero-sized hole and so is a no-op.
+	 */
+	hole_low = pgd_index(USER_LIMIT);
+	hole_high = pgd_index(PAGE_OFFSET);
+
+	pgdidx_limit = pgd_index(limit);
+#if PTRS_PER_PUD > 1
+	pudidx_limit = pud_index(limit);
+#else
+	pudidx_limit = 0;
+#endif
+#if PTRS_PER_PMD > 1
+	pmdidx_limit = pmd_index(limit);
+#else
+	pmdidx_limit = 0;
+#endif
+
+	flush |= (*func)(virt_to_page(pgd), PT_PGD);
+
+	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
 		pud_t *pud;
-		unsigned long pud_limit, pud_next;
 
-		pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP);
+		if (pgdidx >= hole_low && pgdidx < hole_high)
+			continue;
 
-		if (!pgd_val(*pgd))
+		if (!pgd_val(pgd[pgdidx]))
 			continue;
 
-		pud = pud_offset(pgd, 0);
+		pud = pud_offset(&pgd[pgdidx], 0);
 
 		if (PTRS_PER_PUD > 1) /* not folded */
 			flush |= (*func)(virt_to_page(pud), PT_PUD);
 
-		for (; addr != pud_limit; pud++, addr = pud_next) {
+		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
 			pmd_t *pmd;
-			unsigned long pmd_limit;
 
-			pud_next = pud_addr_end(addr, pud_limit);
-
-			if (pud_next < limit)
-				pmd_limit = pud_next;
-			else
-				pmd_limit = limit;
+			if (pgdidx == pgdidx_limit &&
+			    pudidx > pudidx_limit)
+				goto out;
 
-			if (pud_none(*pud))
+			if (pud_none(pud[pudidx]))
 				continue;
 
-			pmd = pmd_offset(pud, 0);
+			pmd = pmd_offset(&pud[pudidx], 0);
 
 			if (PTRS_PER_PMD > 1) /* not folded */
 				flush |= (*func)(virt_to_page(pmd), PT_PMD);
 
-			for (; addr != pmd_limit; pmd++) {
-				addr += (PAGE_SIZE * PTRS_PER_PTE);
-				if ((pmd_limit-1) < (addr-1)) {
-					addr = pmd_limit;
-					break;
-				}
+			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
+				struct page *pte;
+
+				if (pgdidx == pgdidx_limit &&
+				    pudidx == pudidx_limit &&
+				    pmdidx > pmdidx_limit)
+					goto out;
 
-				if (pmd_none(*pmd))
+				if (pmd_none(pmd[pmdidx]))
 					continue;
 
-				flush |= (*func)(pmd_page(*pmd), PT_PTE);
+				pte = pmd_page(pmd[pmdidx]);
+				flush |= (*func)(pte, PT_PTE);
 			}
 		}
 	}
-
-	flush |= (*func)(virt_to_page(pgd_base), PT_PGD);
+out:
 
 	return flush;
 }
@@ -430,20 +719,62 @@ void xen_pgd_pin(pgd_t *pgd)
 {
 	xen_mc_batch();
 
-	if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
+	if (pgd_walk(pgd, pin_page, USER_LIMIT)) {
 		/* re-enable interrupts for kmap_flush_unused */
 		xen_mc_issue(0);
 		kmap_flush_unused();
 		xen_mc_batch();
 	}
 
+#ifdef CONFIG_X86_64
+	{
+		pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
+
+		if (user_pgd) {
+			pin_page(virt_to_page(user_pgd), PT_PGD);
+			xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(user_pgd)));
+		}
+	}
+#else /* CONFIG_X86_32 */
+#ifdef CONFIG_X86_PAE
+	/* Need to make sure unshared kernel PMD is pinnable */
+	pin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
+#endif
 	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
+#endif /* CONFIG_X86_64 */
 	xen_mc_issue(0);
 }
 
-/* The init_mm pagetable is really pinned as soon as its created, but
-   that's before we have page structures to store the bits.  So do all
-   the book-keeping now. */
+/*
+ * On save, we need to pin all pagetables to make sure they get their
+ * mfns turned into pfns.  Search the list for any unpinned pgds and pin
+ * them (unpinned pgds are not currently in use, probably because the
+ * process is under construction or destruction).
+ */
+void xen_mm_pin_all(void)
+{
+	unsigned long flags;
+	struct page *page;
+
+	spin_lock_irqsave(&pgd_lock, flags);
+
+	list_for_each_entry(page, &pgd_list, lru) {
+		if (!PagePinned(page)) {
+			xen_pgd_pin((pgd_t *)page_address(page));
+			SetPageSavePinned(page);
+		}
+	}
+
+	spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
+/*
+ * The init_mm pagetable is really pinned as soon as its created, but
+ * that's before we have page structures to store the bits.  So do all
+ * the book-keeping now.
+ */
 static __init int mark_pinned(struct page *page, enum pt_level level)
 {
 	SetPagePinned(page);
@@ -493,11 +824,49 @@ static void xen_pgd_unpin(pgd_t *pgd)
 
 	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
 
-	pgd_walk(pgd, unpin_page, TASK_SIZE);
+#ifdef CONFIG_X86_64
+	{
+		pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+		if (user_pgd) {
+			xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(user_pgd)));
+			unpin_page(virt_to_page(user_pgd), PT_PGD);
+		}
+	}
+#endif
+
+#ifdef CONFIG_X86_PAE
+	/* Need to make sure unshared kernel PMD is unpinned */
+	pin_page(virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])), PT_PMD);
+#endif
+
+	pgd_walk(pgd, unpin_page, USER_LIMIT);
 
 	xen_mc_issue(0);
 }
 
+/*
+ * On resume, undo any pinning done at save, so that the rest of the
+ * kernel doesn't see any unexpected pinned pagetables.
+ */
+void xen_mm_unpin_all(void)
+{
+	unsigned long flags;
+	struct page *page;
+
+	spin_lock_irqsave(&pgd_lock, flags);
+
+	list_for_each_entry(page, &pgd_list, lru) {
+		if (PageSavePinned(page)) {
+			BUG_ON(!PagePinned(page));
+			xen_pgd_unpin((pgd_t *)page_address(page));
+			ClearPageSavePinned(page);
+		}
+	}
+
+	spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
 void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
 {
 	spin_lock(&next->page_table_lock);
@@ -519,8 +888,15 @@ void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
 static void drop_other_mm_ref(void *info)
 {
 	struct mm_struct *mm = info;
+	struct mm_struct *active_mm;
+
+#ifdef CONFIG_X86_64
+	active_mm = read_pda(active_mm);
+#else
+	active_mm = __get_cpu_var(cpu_tlbstate).active_mm;
+#endif
 
-	if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
+	if (active_mm == mm)
 		leave_mm(smp_processor_id());
 
 	/* If this cpu still has a stale cr3 reference, then make sure
@@ -558,7 +934,7 @@ static void drop_mm_ref(struct mm_struct *mm)
 	}
 
 	if (!cpus_empty(mask))
-		xen_smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
+		smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
 }
 #else
 static void drop_mm_ref(struct mm_struct *mm)
@@ -591,7 +967,7 @@ void xen_exit_mmap(struct mm_struct *mm)
 	spin_lock(&mm->page_table_lock);
 
 	/* pgd may not be pinned in the error exit path of execve */
-	if (PagePinned(virt_to_page(mm->pgd)))
+	if (page_pinned(mm->pgd))
 		xen_pgd_unpin(mm->pgd);
 
 	spin_unlock(&mm->page_table_lock);