Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "Fixes and features for 3.18.

  Apart from the usual cleanups, here is the summary of new features:

   - s390 moves closer towards host large page support

   - PowerPC has improved support for debugging (both inside the guest
     and via gdbstub) and support for e6500 processors

   - ARM/ARM64 support read-only memory (which is necessary to put
     firmware in emulated NOR flash)

   - x86 has the usual emulator fixes and nested virtualization
     improvements (including improved Windows support on Intel and
     Jailhouse hypervisor support on AMD), adaptive PLE which helps
     overcommitting of huge guests.  Also included are some patches that
     make KVM more friendly to memory hot-unplug, and fixes for rare
     caching bugs.

  Two patches have trivial mm/ parts that were acked by Rik and Andrew.

  Note: I will soon switch to a subkey for signing purposes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (157 commits)
  kvm: do not handle APIC access page if in-kernel irqchip is not in use
  KVM: s390: count vcpu wakeups in stat.halt_wakeup
  KVM: s390/facilities: allow TOD-CLOCK steering facility bit
  KVM: PPC: BOOK3S: HV: CMA: Reserve cma region only in hypervisor mode
  arm/arm64: KVM: Report correct FSC for unsupported fault types
  arm/arm64: KVM: Fix VTTBR_BADDR_MASK and pgd alloc
  kvm: Fix kvm_get_page_retry_io __gup retval check
  arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset
  kvm: x86: Unpin and remove kvm_arch->apic_access_page
  kvm: vmx: Implement set_apic_access_page_addr
  kvm: x86: Add request bit to reload APIC access page address
  kvm: Add arch specific mmu notifier for page invalidation
  kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
  kvm: Fix page ageing bugs
  kvm/x86/mmu: Pass gfn and level to rmapp callback.
  x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only
  kvm: x86: use macros to compute bank MSRs
  KVM: x86: Remove debug assertion of non-PAE reserved bits
  kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
  kvm: Faults which trigger IO release the mmap_sem
  ...

1 files changed, 327 insertions, 380 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 5404a6261db9..296b61a4af59 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -145,30 +145,56 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
 /**
  * gmap_alloc - allocate a guest address space
  * @mm: pointer to the parent mm_struct
+ * @limit: maximum size of the gmap address space
  *
  * Returns a guest address space structure.
  */
-struct gmap *gmap_alloc(struct mm_struct *mm)
+struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
 {
 	struct gmap *gmap;
 	struct page *page;
 	unsigned long *table;
-
+	unsigned long etype, atype;
+
+	if (limit < (1UL << 31)) {
+		limit = (1UL << 31) - 1;
+		atype = _ASCE_TYPE_SEGMENT;
+		etype = _SEGMENT_ENTRY_EMPTY;
+	} else if (limit < (1UL << 42)) {
+		limit = (1UL << 42) - 1;
+		atype = _ASCE_TYPE_REGION3;
+		etype = _REGION3_ENTRY_EMPTY;
+	} else if (limit < (1UL << 53)) {
+		limit = (1UL << 53) - 1;
+		atype = _ASCE_TYPE_REGION2;
+		etype = _REGION2_ENTRY_EMPTY;
+	} else {
+		limit = -1UL;
+		atype = _ASCE_TYPE_REGION1;
+		etype = _REGION1_ENTRY_EMPTY;
+	}
 	gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
 	if (!gmap)
 		goto out;
 	INIT_LIST_HEAD(&gmap->crst_list);
+	INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
+	INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
+	spin_lock_init(&gmap->guest_table_lock);
 	gmap->mm = mm;
 	page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
 	if (!page)
 		goto out_free;
+	page->index = 0;
 	list_add(&page->lru, &gmap->crst_list);
 	table = (unsigned long *) page_to_phys(page);
-	crst_table_init(table, _REGION1_ENTRY_EMPTY);
+	crst_table_init(table, etype);
 	gmap->table = table;
-	gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
-		     _ASCE_USER_BITS | __pa(table);
+	gmap->asce = atype | _ASCE_TABLE_LENGTH |
+		_ASCE_USER_BITS | __pa(table);
+	gmap->asce_end = limit;
+	down_write(&mm->mmap_sem);
 	list_add(&gmap->list, &mm->context.gmap_list);
+	up_write(&mm->mmap_sem);
 	return gmap;
 
 out_free:
@@ -178,36 +204,38 @@ out:
 }
 EXPORT_SYMBOL_GPL(gmap_alloc);
 
-static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
-{
-	struct gmap_pgtable *mp;
-	struct gmap_rmap *rmap;
-	struct page *page;
-
-	if (*table & _SEGMENT_ENTRY_INVALID)
-		return 0;
-	page = pfn_to_page(*table >> PAGE_SHIFT);
-	mp = (struct gmap_pgtable *) page->index;
-	list_for_each_entry(rmap, &mp->mapper, list) {
-		if (rmap->entry != table)
-			continue;
-		list_del(&rmap->list);
-		kfree(rmap);
-		break;
-	}
-	*table = mp->vmaddr | _SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_PROTECT;
-	return 1;
-}
-
 static void gmap_flush_tlb(struct gmap *gmap)
 {
 	if (MACHINE_HAS_IDTE)
-		__tlb_flush_asce(gmap->mm, (unsigned long) gmap->table |
-				 _ASCE_TYPE_REGION1);
+		__tlb_flush_asce(gmap->mm, gmap->asce);
 	else
 		__tlb_flush_global();
 }
 
+static void gmap_radix_tree_free(struct radix_tree_root *root)
+{
+	struct radix_tree_iter iter;
+	unsigned long indices[16];
+	unsigned long index;
+	void **slot;
+	int i, nr;
+
+	/* A radix tree is freed by deleting all of its entries */
+	index = 0;
+	do {
+		nr = 0;
+		radix_tree_for_each_slot(slot, root, &iter, index) {
+			indices[nr] = iter.index;
+			if (++nr == 16)
+				break;
+		}
+		for (i = 0; i < nr; i++) {
+			index = indices[i];
+			radix_tree_delete(root, index);
+		}
+	} while (nr > 0);
+}
+
 /**
  * gmap_free - free a guest address space
  * @gmap: pointer to the guest address space structure
@@ -215,31 +243,21 @@ static void gmap_flush_tlb(struct gmap *gmap)
 void gmap_free(struct gmap *gmap)
 {
 	struct page *page, *next;
-	unsigned long *table;
-	int i;
-
 
 	/* Flush tlb. */
 	if (MACHINE_HAS_IDTE)
-		__tlb_flush_asce(gmap->mm, (unsigned long) gmap->table |
-				 _ASCE_TYPE_REGION1);
+		__tlb_flush_asce(gmap->mm, gmap->asce);
 	else
 		__tlb_flush_global();
 
 	/* Free all segment & region tables. */
-	down_read(&gmap->mm->mmap_sem);
-	spin_lock(&gmap->mm->page_table_lock);
-	list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
-		table = (unsigned long *) page_to_phys(page);
-		if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
-			/* Remove gmap rmap structures for segment table. */
-			for (i = 0; i < PTRS_PER_PMD; i++, table++)
-				gmap_unlink_segment(gmap, table);
+	list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
 		__free_pages(page, ALLOC_ORDER);
-	}
-	spin_unlock(&gmap->mm->page_table_lock);
-	up_read(&gmap->mm->mmap_sem);
+	gmap_radix_tree_free(&gmap->guest_to_host);
+	gmap_radix_tree_free(&gmap->host_to_guest);
+	down_write(&gmap->mm->mmap_sem);
 	list_del(&gmap->list);
+	up_write(&gmap->mm->mmap_sem);
 	kfree(gmap);
 }
 EXPORT_SYMBOL_GPL(gmap_free);
@@ -267,42 +285,97 @@ EXPORT_SYMBOL_GPL(gmap_disable);
 /*
  * gmap_alloc_table is assumed to be called with mmap_sem held
  */
-static int gmap_alloc_table(struct gmap *gmap,
-			    unsigned long *table, unsigned long init)
-	__releases(&gmap->mm->page_table_lock)
-	__acquires(&gmap->mm->page_table_lock)
+static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
+			    unsigned long init, unsigned long gaddr)
 {
 	struct page *page;
 	unsigned long *new;
 
 	/* since we dont free the gmap table until gmap_free we can unlock */
-	spin_unlock(&gmap->mm->page_table_lock);
 	page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
-	spin_lock(&gmap->mm->page_table_lock);
 	if (!page)
 		return -ENOMEM;
 	new = (unsigned long *) page_to_phys(page);
 	crst_table_init(new, init);
+	spin_lock(&gmap->mm->page_table_lock);
 	if (*table & _REGION_ENTRY_INVALID) {
 		list_add(&page->lru, &gmap->crst_list);
 		*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
 			(*table & _REGION_ENTRY_TYPE_MASK);
-	} else
+		page->index = gaddr;
+		page = NULL;
+	}
+	spin_unlock(&gmap->mm->page_table_lock);
+	if (page)
 		__free_pages(page, ALLOC_ORDER);
 	return 0;
 }
 
 /**
+ * __gmap_segment_gaddr - find virtual address from segment pointer
+ * @entry: pointer to a segment table entry in the guest address space
+ *
+ * Returns the virtual address in the guest address space for the segment
+ */
+static unsigned long __gmap_segment_gaddr(unsigned long *entry)
+{
+	struct page *page;
+	unsigned long offset;
+
+	offset = (unsigned long) entry / sizeof(unsigned long);
+	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
+	page = pmd_to_page((pmd_t *) entry);
+	return page->index + offset;
+}
+
+/**
+ * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
+ * @gmap: pointer to the guest address space structure
+ * @vmaddr: address in the host process address space
+ *
+ * Returns 1 if a TLB flush is required
+ */
+static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
+{
+	unsigned long *entry;
+	int flush = 0;
+
+	spin_lock(&gmap->guest_table_lock);
+	entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
+	if (entry) {
+		flush = (*entry != _SEGMENT_ENTRY_INVALID);
+		*entry = _SEGMENT_ENTRY_INVALID;
+	}
+	spin_unlock(&gmap->guest_table_lock);
+	return flush;
+}
+
+/**
+ * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
+ * @gmap: pointer to the guest address space structure
+ * @gaddr: address in the guest address space
+ *
+ * Returns 1 if a TLB flush is required
+ */
+static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
+{
+	unsigned long vmaddr;
+
+	vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
+						   gaddr >> PMD_SHIFT);
+	return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
+}
+
+/**
  * gmap_unmap_segment - unmap segment from the guest address space
  * @gmap: pointer to the guest address space structure
- * @addr: address in the guest address space
+ * @to: address in the guest address space
  * @len: length of the memory area to unmap
  *
  * Returns 0 if the unmap succeeded, -EINVAL if not.
  */
 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
 {
-	unsigned long *table;
 	unsigned long off;
 	int flush;
 
@@ -312,31 +385,10 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
 		return -EINVAL;
 
 	flush = 0;
-	down_read(&gmap->mm->mmap_sem);
-	spin_lock(&gmap->mm->page_table_lock);
-	for (off = 0; off < len; off += PMD_SIZE) {
-		/* Walk the guest addr space page table */
-		table = gmap->table + (((to + off) >> 53) & 0x7ff);
-		if (*table & _REGION_ENTRY_INVALID)
-			goto out;
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 42) & 0x7ff);
-		if (*table & _REGION_ENTRY_INVALID)
-			goto out;
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 31) & 0x7ff);
-		if (*table & _REGION_ENTRY_INVALID)
-			goto out;
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 20) & 0x7ff);
-
-		/* Clear segment table entry in guest address space. */
-		flush |= gmap_unlink_segment(gmap, table);
-		*table = _SEGMENT_ENTRY_INVALID;
-	}
-out:
-	spin_unlock(&gmap->mm->page_table_lock);
-	up_read(&gmap->mm->mmap_sem);
+	down_write(&gmap->mm->mmap_sem);
+	for (off = 0; off < len; off += PMD_SIZE)
+		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
+	up_write(&gmap->mm->mmap_sem);
 	if (flush)
 		gmap_flush_tlb(gmap);
 	return 0;
@@ -348,87 +400,47 @@ EXPORT_SYMBOL_GPL(gmap_unmap_segment);
  * @gmap: pointer to the guest address space structure
  * @from: source address in the parent address space
  * @to: target address in the guest address space
+ * @len: length of the memory area to map
  *
  * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
  */
 int gmap_map_segment(struct gmap *gmap, unsigned long from,
 		     unsigned long to, unsigned long len)
 {
-	unsigned long *table;
 	unsigned long off;
 	int flush;
 
 	if ((from | to | len) & (PMD_SIZE - 1))
 		return -EINVAL;
-	if (len == 0 || from + len > TASK_MAX_SIZE ||
-	    from + len < from || to + len < to)
+	if (len == 0 || from + len < from || to + len < to ||
+	    from + len > TASK_MAX_SIZE || to + len > gmap->asce_end)
 		return -EINVAL;
 
 	flush = 0;
-	down_read(&gmap->mm->mmap_sem);
-	spin_lock(&gmap->mm->page_table_lock);
+	down_write(&gmap->mm->mmap_sem);
 	for (off = 0; off < len; off += PMD_SIZE) {
-		/* Walk the gmap address space page table */
-		table = gmap->table + (((to + off) >> 53) & 0x7ff);
-		if ((*table & _REGION_ENTRY_INVALID) &&
-		    gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
-			goto out_unmap;
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 42) & 0x7ff);
-		if ((*table & _REGION_ENTRY_INVALID) &&
-		    gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
-			goto out_unmap;
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 31) & 0x7ff);
-		if ((*table & _REGION_ENTRY_INVALID) &&
-		    gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
-			goto out_unmap;
-		table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
-		table = table + (((to + off) >> 20) & 0x7ff);
-
-		/* Store 'from' address in an invalid segment table entry. */
-		flush |= gmap_unlink_segment(gmap, table);
-		*table =  (from + off) | (_SEGMENT_ENTRY_INVALID |
-					  _SEGMENT_ENTRY_PROTECT);
+		/* Remove old translation */
+		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
+		/* Store new translation */
+		if (radix_tree_insert(&gmap->guest_to_host,
+				      (to + off) >> PMD_SHIFT,
+				      (void *) from + off))
+			break;
 	}
-	spin_unlock(&gmap->mm->page_table_lock);
-	up_read(&gmap->mm->mmap_sem);
+	up_write(&gmap->mm->mmap_sem);
 	if (flush)
 		gmap_flush_tlb(gmap);
-	return 0;
-
-out_unmap:
-	spin_unlock(&gmap->mm->page_table_lock);
-	up_read(&gmap->mm->mmap_sem);
+	if (off >= len)
+		return 0;
 	gmap_unmap_segment(gmap, to, len);
 	return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(gmap_map_segment);
 
-static unsigned long *gmap_table_walk(unsigned long address, struct gmap *gmap)
-{
-	unsigned long *table;
-
-	table = gmap->table + ((address >> 53) & 0x7ff);
-	if (unlikely(*table & _REGION_ENTRY_INVALID))
-		return ERR_PTR(-EFAULT);
-	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-	table = table + ((address >> 42) & 0x7ff);
-	if (unlikely(*table & _REGION_ENTRY_INVALID))
-		return ERR_PTR(-EFAULT);
-	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-	table = table + ((address >> 31) & 0x7ff);
-	if (unlikely(*table & _REGION_ENTRY_INVALID))
-		return ERR_PTR(-EFAULT);
-	table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-	table = table + ((address >> 20) & 0x7ff);
-	return table;
-}
-
 /**
  * __gmap_translate - translate a guest address to a user space address
- * @address: guest address
  * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
  *
  * Returns user space address which corresponds to the guest address or
  * -EFAULT if no such mapping exists.
@@ -436,168 +448,161 @@ static unsigned long *gmap_table_walk(unsigned long address, struct gmap *gmap)
  * The mmap_sem of the mm that belongs to the address space must be held
  * when this function gets called.
  */
-unsigned long __gmap_translate(unsigned long address, struct gmap *gmap)
+unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
 {
-	unsigned long *segment_ptr, vmaddr, segment;
-	struct gmap_pgtable *mp;
-	struct page *page;
+	unsigned long vmaddr;
 
-	current->thread.gmap_addr = address;
-	segment_ptr = gmap_table_walk(address, gmap);
-	if (IS_ERR(segment_ptr))
-		return PTR_ERR(segment_ptr);
-	/* Convert the gmap address to an mm address. */
-	segment = *segment_ptr;
-	if (!(segment & _SEGMENT_ENTRY_INVALID)) {
-		page = pfn_to_page(segment >> PAGE_SHIFT);
-		mp = (struct gmap_pgtable *) page->index;
-		return mp->vmaddr | (address & ~PMD_MASK);
-	} else if (segment & _SEGMENT_ENTRY_PROTECT) {
-		vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
-		return vmaddr | (address & ~PMD_MASK);
-	}
-	return -EFAULT;
+	vmaddr = (unsigned long)
+		radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
+	return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
 }
 EXPORT_SYMBOL_GPL(__gmap_translate);
 
 /**
  * gmap_translate - translate a guest address to a user space address
- * @address: guest address
  * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
  *
  * Returns user space address which corresponds to the guest address or
  * -EFAULT if no such mapping exists.
  * This function does not establish potentially missing page table entries.
  */
-unsigned long gmap_translate(unsigned long address, struct gmap *gmap)
+unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
 {
 	unsigned long rc;
 
 	down_read(&gmap->mm->mmap_sem);
-	rc = __gmap_translate(address, gmap);
+	rc = __gmap_translate(gmap, gaddr);
 	up_read(&gmap->mm->mmap_sem);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_translate);
 
-static int gmap_connect_pgtable(unsigned long address, unsigned long segment,
-				unsigned long *segment_ptr, struct gmap *gmap)
+/**
+ * gmap_unlink - disconnect a page table from the gmap shadow tables
+ * @gmap: pointer to guest mapping meta data structure
+ * @table: pointer to the host page table
+ * @vmaddr: vm address associated with the host page table
+ */
+static void gmap_unlink(struct mm_struct *mm, unsigned long *table,
+			unsigned long vmaddr)
+{
+	struct gmap *gmap;
+	int flush;
+
+	list_for_each_entry(gmap, &mm->context.gmap_list, list) {
+		flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
+		if (flush)
+			gmap_flush_tlb(gmap);
+	}
+}
+
+/**
+ * gmap_link - set up shadow page tables to connect a host to a guest address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ * @vmaddr: vm address
+ *
+ * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
+ * if the vm address is already mapped to a different guest segment.
+ * The mmap_sem of the mm that belongs to the address space must be held
+ * when this function gets called.
+ */
+int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
 {
-	unsigned long vmaddr;
-	struct vm_area_struct *vma;
-	struct gmap_pgtable *mp;
-	struct gmap_rmap *rmap;
 	struct mm_struct *mm;
-	struct page *page;
+	unsigned long *table;
+	spinlock_t *ptl;
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
+	int rc;
 
-	mm = gmap->mm;
-	vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
-	vma = find_vma(mm, vmaddr);
-	if (!vma || vma->vm_start > vmaddr)
-		return -EFAULT;
+	/* Create higher level tables in the gmap page table */
+	table = gmap->table;
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
+		table += (gaddr >> 53) & 0x7ff;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
+				     gaddr & 0xffe0000000000000))
+			return -ENOMEM;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+	}
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
+		table += (gaddr >> 42) & 0x7ff;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
+				     gaddr & 0xfffffc0000000000))
+			return -ENOMEM;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+	}
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
+		table += (gaddr >> 31) & 0x7ff;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
+				     gaddr & 0xffffffff80000000))
+			return -ENOMEM;
+		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+	}
+	table += (gaddr >> 20) & 0x7ff;
 	/* Walk the parent mm page table */
+	mm = gmap->mm;
 	pgd = pgd_offset(mm, vmaddr);
-	pud = pud_alloc(mm, pgd, vmaddr);
-	if (!pud)
-		return -ENOMEM;
-	pmd = pmd_alloc(mm, pud, vmaddr);
-	if (!pmd)
-		return -ENOMEM;
-	if (!pmd_present(*pmd) &&
-	    __pte_alloc(mm, vma, pmd, vmaddr))
-		return -ENOMEM;
+	VM_BUG_ON(pgd_none(*pgd));
+	pud = pud_offset(pgd, vmaddr);
+	VM_BUG_ON(pud_none(*pud));
+	pmd = pmd_offset(pud, vmaddr);
+	VM_BUG_ON(pmd_none(*pmd));
 	/* large pmds cannot yet be handled */
 	if (pmd_large(*pmd))
 		return -EFAULT;
-	/* pmd now points to a valid segment table entry. */
-	rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
-	if (!rmap)
-		return -ENOMEM;
 	/* Link gmap segment table entry location to page table. */
-	page = pmd_page(*pmd);
-	mp = (struct gmap_pgtable *) page->index;
-	rmap->gmap = gmap;
-	rmap->entry = segment_ptr;
-	rmap->vmaddr = address & PMD_MASK;
-	spin_lock(&mm->page_table_lock);
-	if (*segment_ptr == segment) {
-		list_add(&rmap->list, &mp->mapper);
-		/* Set gmap segment table entry to page table. */
-		*segment_ptr = pmd_val(*pmd) & PAGE_MASK;
-		rmap = NULL;
-	}
-	spin_unlock(&mm->page_table_lock);
-	kfree(rmap);
-	return 0;
-}
-
-static void gmap_disconnect_pgtable(struct mm_struct *mm, unsigned long *table)
-{
-	struct gmap_rmap *rmap, *next;
-	struct gmap_pgtable *mp;
-	struct page *page;
-	int flush;
-
-	flush = 0;
-	spin_lock(&mm->page_table_lock);
-	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
-	mp = (struct gmap_pgtable *) page->index;
-	list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
-		*rmap->entry = mp->vmaddr | (_SEGMENT_ENTRY_INVALID |
-					     _SEGMENT_ENTRY_PROTECT);
-		list_del(&rmap->list);
-		kfree(rmap);
-		flush = 1;
-	}
-	spin_unlock(&mm->page_table_lock);
-	if (flush)
-		__tlb_flush_global();
+	rc = radix_tree_preload(GFP_KERNEL);
+	if (rc)
+		return rc;
+	ptl = pmd_lock(mm, pmd);
+	spin_lock(&gmap->guest_table_lock);
+	if (*table == _SEGMENT_ENTRY_INVALID) {
+		rc = radix_tree_insert(&gmap->host_to_guest,
+				       vmaddr >> PMD_SHIFT, table);
+		if (!rc)
+			*table = pmd_val(*pmd);
+	} else
+		rc = 0;
+	spin_unlock(&gmap->guest_table_lock);
+	spin_unlock(ptl);
+	radix_tree_preload_end();
+	return rc;
 }
 
-/*
- * this function is assumed to be called with mmap_sem held
+/**
+ * gmap_fault - resolve a fault on a guest address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ * @fault_flags: flags to pass down to handle_mm_fault()
+ *
+ * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
+ * if the vm address is already mapped to a different guest segment.
  */
-unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
+int gmap_fault(struct gmap *gmap, unsigned long gaddr,
+	       unsigned int fault_flags)
 {
-	unsigned long *segment_ptr, segment;
-	struct gmap_pgtable *mp;
-	struct page *page;
+	unsigned long vmaddr;
 	int rc;
 
-	current->thread.gmap_addr = address;
-	segment_ptr = gmap_table_walk(address, gmap);
-	if (IS_ERR(segment_ptr))
-		return -EFAULT;
-	/* Convert the gmap address to an mm address. */
-	while (1) {
-		segment = *segment_ptr;
-		if (!(segment & _SEGMENT_ENTRY_INVALID)) {
-			/* Page table is present */
-			page = pfn_to_page(segment >> PAGE_SHIFT);
-			mp = (struct gmap_pgtable *) page->index;
-			return mp->vmaddr | (address & ~PMD_MASK);
-		}
-		if (!(segment & _SEGMENT_ENTRY_PROTECT))
-			/* Nothing mapped in the gmap address space. */
-			break;
-		rc = gmap_connect_pgtable(address, segment, segment_ptr, gmap);
-		if (rc)
-			return rc;
-	}
-	return -EFAULT;
-}
-
-unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
-{
-	unsigned long rc;
-
 	down_read(&gmap->mm->mmap_sem);
-	rc = __gmap_fault(address, gmap);
+	vmaddr = __gmap_translate(gmap, gaddr);
+	if (IS_ERR_VALUE(vmaddr)) {
+		rc = vmaddr;
+		goto out_up;
+	}
+	if (fixup_user_fault(current, gmap->mm, vmaddr, fault_flags)) {
+		rc = -EFAULT;
+		goto out_up;
+	}
+	rc = __gmap_link(gmap, gaddr, vmaddr);
+out_up:
 	up_read(&gmap->mm->mmap_sem);
-
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_fault);
@@ -617,17 +622,24 @@ static void gmap_zap_swap_entry(swp_entry_t entry, struct mm_struct *mm)
 	free_swap_and_cache(entry);
 }
 
-/**
- * The mm->mmap_sem lock must be held
+/*
+ * this function is assumed to be called with mmap_sem held
  */
-static void gmap_zap_unused(struct mm_struct *mm, unsigned long address)
+void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
 {
-	unsigned long ptev, pgstev;
+	unsigned long vmaddr, ptev, pgstev;
+	pte_t *ptep, pte;
 	spinlock_t *ptl;
 	pgste_t pgste;
-	pte_t *ptep, pte;
 
-	ptep = get_locked_pte(mm, address, &ptl);
+	/* Find the vm address for the guest address */
+	vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
+						   gaddr >> PMD_SHIFT);
+	if (!vmaddr)
+		return;
+	vmaddr |= gaddr & ~PMD_MASK;
+	/* Get pointer to the page table entry */
+	ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
 	if (unlikely(!ptep))
 		return;
 	pte = *ptep;
@@ -639,87 +651,34 @@ static void gmap_zap_unused(struct mm_struct *mm, unsigned long address)
 	ptev = pte_val(pte);
 	if (((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED) ||
 	    ((pgstev & _PGSTE_GPS_ZERO) && (ptev & _PAGE_INVALID))) {
-		gmap_zap_swap_entry(pte_to_swp_entry(pte), mm);
-		pte_clear(mm, address, ptep);
+		gmap_zap_swap_entry(pte_to_swp_entry(pte), gmap->mm);
+		pte_clear(gmap->mm, vmaddr, ptep);
 	}
 	pgste_set_unlock(ptep, pgste);
 out_pte:
 	pte_unmap_unlock(*ptep, ptl);
 }
-
-/*
- * this function is assumed to be called with mmap_sem held
- */
-void __gmap_zap(unsigned long address, struct gmap *gmap)
-{
-	unsigned long *table, *segment_ptr;
-	unsigned long segment, pgstev, ptev;
-	struct gmap_pgtable *mp;
-	struct page *page;
-
-	segment_ptr = gmap_table_walk(address, gmap);
-	if (IS_ERR(segment_ptr))
-		return;
-	segment = *segment_ptr;
-	if (segment & _SEGMENT_ENTRY_INVALID)
-		return;
-	page = pfn_to_page(segment >> PAGE_SHIFT);
-	mp = (struct gmap_pgtable *) page->index;
-	address = mp->vmaddr | (address & ~PMD_MASK);
-	/* Page table is present */
-	table = (unsigned long *)(segment & _SEGMENT_ENTRY_ORIGIN);
-	table = table + ((address >> 12) & 0xff);
-	pgstev = table[PTRS_PER_PTE];
-	ptev = table[0];
-	/* quick check, checked again with locks held */
-	if (((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED) ||
-	    ((pgstev & _PGSTE_GPS_ZERO) && (ptev & _PAGE_INVALID)))
-		gmap_zap_unused(gmap->mm, address);
-}
 EXPORT_SYMBOL_GPL(__gmap_zap);
 
-void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap)
+void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
 {
-
-	unsigned long *table, address, size;
+	unsigned long gaddr, vmaddr, size;
 	struct vm_area_struct *vma;
-	struct gmap_pgtable *mp;
-	struct page *page;
 
 	down_read(&gmap->mm->mmap_sem);
-	address = from;
-	while (address < to) {
-		/* Walk the gmap address space page table */
-		table = gmap->table + ((address >> 53) & 0x7ff);
-		if (unlikely(*table & _REGION_ENTRY_INVALID)) {
-			address = (address + PMD_SIZE) & PMD_MASK;
-			continue;
-		}
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + ((address >> 42) & 0x7ff);
-		if (unlikely(*table & _REGION_ENTRY_INVALID)) {
-			address = (address + PMD_SIZE) & PMD_MASK;
+	for (gaddr = from; gaddr < to;
+	     gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
+		/* Find the vm address for the guest address */
+		vmaddr = (unsigned long)
+			radix_tree_lookup(&gmap->guest_to_host,
+					  gaddr >> PMD_SHIFT);
+		if (!vmaddr)
 			continue;
-		}
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + ((address >> 31) & 0x7ff);
-		if (unlikely(*table & _REGION_ENTRY_INVALID)) {
-			address = (address + PMD_SIZE) & PMD_MASK;
-			continue;
-		}
-		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
-		table = table + ((address >> 20) & 0x7ff);
-		if (unlikely(*table & _SEGMENT_ENTRY_INVALID)) {
-			address = (address + PMD_SIZE) & PMD_MASK;
-			continue;
-		}
-		page = pfn_to_page(*table >> PAGE_SHIFT);
-		mp = (struct gmap_pgtable *) page->index;
-		vma = find_vma(gmap->mm, mp->vmaddr);
-		size = min(to - address, PMD_SIZE - (address & ~PMD_MASK));
-		zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK),
-			       size, NULL);
-		address = (address + PMD_SIZE) & PMD_MASK;
+		vmaddr |= gaddr & ~PMD_MASK;
+		/* Find vma in the parent mm */
+		vma = find_vma(gmap->mm, vmaddr);
+		size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
+		zap_page_range(vma, vmaddr, size, NULL);
 	}
 	up_read(&gmap->mm->mmap_sem);
 }
@@ -755,7 +714,7 @@ EXPORT_SYMBOL_GPL(gmap_unregister_ipte_notifier);
 /**
  * gmap_ipte_notify - mark a range of ptes for invalidation notification
  * @gmap: pointer to guest mapping meta data structure
- * @start: virtual address in the guest address space
+ * @gaddr: virtual address in the guest address space
  * @len: size of area
  *
  * Returns 0 if for each page in the given range a gmap mapping exists and
@@ -763,7 +722,7 @@ EXPORT_SYMBOL_GPL(gmap_unregister_ipte_notifier);
  * for one or more pages -EFAULT is returned. If no memory could be allocated
  * -ENOMEM is returned. This function establishes missing page table entries.
  */
-int gmap_ipte_notify(struct gmap *gmap, unsigned long start, unsigned long len)
+int gmap_ipte_notify(struct gmap *gmap, unsigned long gaddr, unsigned long len)
 {
 	unsigned long addr;
 	spinlock_t *ptl;
@@ -771,12 +730,12 @@ int gmap_ipte_notify(struct gmap *gmap, unsigned long start, unsigned long len)
 	pgste_t pgste;
 	int rc = 0;
 
-	if ((start & ~PAGE_MASK) || (len & ~PAGE_MASK))
+	if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK))
 		return -EINVAL;
 	down_read(&gmap->mm->mmap_sem);
 	while (len) {
 		/* Convert gmap address and connect the page tables */
-		addr = __gmap_fault(start, gmap);
+		addr = __gmap_translate(gmap, gaddr);
 		if (IS_ERR_VALUE(addr)) {
 			rc = addr;
 			break;
@@ -786,6 +745,9 @@ int gmap_ipte_notify(struct gmap *gmap, unsigned long start, unsigned long len)
 			rc = -EFAULT;
 			break;
 		}
+		rc = __gmap_link(gmap, gaddr, addr);
+		if (rc)
+			break;
 		/* Walk the process page table, lock and get pte pointer */
 		ptep = get_locked_pte(gmap->mm, addr, &ptl);
 		if (unlikely(!ptep))
@@ -796,7 +758,7 @@ int gmap_ipte_notify(struct gmap *gmap, unsigned long start, unsigned long len)
 			pgste = pgste_get_lock(ptep);
 			pgste_val(pgste) |= PGSTE_IN_BIT;
 			pgste_set_unlock(ptep, pgste);
-			start += PAGE_SIZE;
+			gaddr += PAGE_SIZE;
 			len -= PAGE_SIZE;
 		}
 		spin_unlock(ptl);
@@ -809,28 +771,30 @@ EXPORT_SYMBOL_GPL(gmap_ipte_notify);
 /**
  * gmap_do_ipte_notify - call all invalidation callbacks for a specific pte.
  * @mm: pointer to the process mm_struct
+ * @addr: virtual address in the process address space
  * @pte: pointer to the page table entry
  *
  * This function is assumed to be called with the page table lock held
  * for the pte to notify.
  */
-void gmap_do_ipte_notify(struct mm_struct *mm, pte_t *pte)
+void gmap_do_ipte_notify(struct mm_struct *mm, unsigned long vmaddr, pte_t *pte)
 {
-	unsigned long segment_offset;
+	unsigned long offset, gaddr;
+	unsigned long *table;
 	struct gmap_notifier *nb;
-	struct gmap_pgtable *mp;
-	struct gmap_rmap *rmap;
-	struct page *page;
+	struct gmap *gmap;
 
-	segment_offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
-	segment_offset = segment_offset * (4096 / sizeof(pte_t));
-	page = pfn_to_page(__pa(pte) >> PAGE_SHIFT);
-	mp = (struct gmap_pgtable *) page->index;
+	offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
+	offset = offset * (4096 / sizeof(pte_t));
 	spin_lock(&gmap_notifier_lock);
-	list_for_each_entry(rmap, &mp->mapper, list) {
+	list_for_each_entry(gmap, &mm->context.gmap_list, list) {
+		table = radix_tree_lookup(&gmap->host_to_guest,
+					  vmaddr >> PMD_SHIFT);
+		if (!table)
+			continue;
+		gaddr = __gmap_segment_gaddr(table) + offset;
 		list_for_each_entry(nb, &gmap_notifier_list, list)
-			nb->notifier_call(rmap->gmap,
-					  rmap->vmaddr + segment_offset);
+			nb->notifier_call(gmap, gaddr);
 	}
 	spin_unlock(&gmap_notifier_lock);
 }
@@ -841,29 +805,18 @@ static inline int page_table_with_pgste(struct page *page)
 	return atomic_read(&page->_mapcount) == 0;
 }
 
-static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
-						    unsigned long vmaddr)
+static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm)
 {
 	struct page *page;
 	unsigned long *table;
-	struct gmap_pgtable *mp;
 
 	page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 	if (!page)
 		return NULL;
-	mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
-	if (!mp) {
-		__free_page(page);
-		return NULL;
-	}
 	if (!pgtable_page_ctor(page)) {
-		kfree(mp);
 		__free_page(page);
 		return NULL;
 	}
-	mp->vmaddr = vmaddr & PMD_MASK;
-	INIT_LIST_HEAD(&mp->mapper);
-	page->index = (unsigned long) mp;
 	atomic_set(&page->_mapcount, 0);
 	table = (unsigned long *) page_to_phys(page);
 	clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
@@ -874,14 +827,10 @@ static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 static inline void page_table_free_pgste(unsigned long *table)
 {
 	struct page *page;
-	struct gmap_pgtable *mp;
 
 	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
-	mp = (struct gmap_pgtable *) page->index;
-	BUG_ON(!list_empty(&mp->mapper));
 	pgtable_page_dtor(page);
 	atomic_set(&page->_mapcount, -1);
-	kfree(mp);
 	__free_page(page);
 }
 
@@ -994,13 +943,13 @@ retry:
 	}
 	if (!(pte_val(*ptep) & _PAGE_INVALID) &&
 	     (pte_val(*ptep) & _PAGE_PROTECT)) {
-			pte_unmap_unlock(*ptep, ptl);
-			if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) {
-				up_read(&mm->mmap_sem);
-				return -EFAULT;
-			}
-			goto retry;
+		pte_unmap_unlock(*ptep, ptl);
+		if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) {
+			up_read(&mm->mmap_sem);
+			return -EFAULT;
 		}
+		goto retry;
+	}
 
 	new = old = pgste_get_lock(ptep);
 	pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
@@ -1038,8 +987,7 @@ static inline int page_table_with_pgste(struct page *page)
 	return 0;
 }
 
-static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
-						    unsigned long vmaddr)
+static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm)
 {
 	return NULL;
 }
@@ -1053,8 +1001,8 @@ static inline void page_table_free_pgste(unsigned long *table)
 {
 }
 
-static inline void gmap_disconnect_pgtable(struct mm_struct *mm,
-					   unsigned long *table)
+static inline void gmap_unlink(struct mm_struct *mm, unsigned long *table,
+			unsigned long vmaddr)
 {
 }
 
@@ -1074,14 +1022,14 @@ static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
 /*
  * page table entry allocation/free routines.
  */
-unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
+unsigned long *page_table_alloc(struct mm_struct *mm)
 {
 	unsigned long *uninitialized_var(table);
 	struct page *uninitialized_var(page);
 	unsigned int mask, bit;
 
 	if (mm_has_pgste(mm))
-		return page_table_alloc_pgste(mm, vmaddr);
+		return page_table_alloc_pgste(mm);
 	/* Allocate fragments of a 4K page as 1K/2K page table */
 	spin_lock_bh(&mm->context.list_lock);
 	mask = FRAG_MASK;
@@ -1123,10 +1071,8 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
 	unsigned int bit, mask;
 
 	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
-	if (page_table_with_pgste(page)) {
-		gmap_disconnect_pgtable(mm, table);
+	if (page_table_with_pgste(page))
 		return page_table_free_pgste(table);
-	}
 	/* Free 1K/2K page table fragment of a 4K page */
 	bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
 	spin_lock_bh(&mm->context.list_lock);
@@ -1158,7 +1104,8 @@ static void __page_table_free_rcu(void *table, unsigned bit)
 	}
 }
 
-void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
+void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
+			 unsigned long vmaddr)
 {
 	struct mm_struct *mm;
 	struct page *page;
@@ -1167,7 +1114,7 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
 	mm = tlb->mm;
 	page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 	if (page_table_with_pgste(page)) {
-		gmap_disconnect_pgtable(mm, table);
+		gmap_unlink(mm, table, vmaddr);
 		table = (unsigned long *) (__pa(table) | FRAG_MASK);
 		tlb_remove_table(tlb, table);
 		return;
@@ -1303,7 +1250,7 @@ again:
 		if (page_table_with_pgste(page))
 			continue;
 		/* Allocate new page table with pgstes */
-		new = page_table_alloc_pgste(mm, addr);
+		new = page_table_alloc_pgste(mm);
 		if (!new)
 			return -ENOMEM;
 
@@ -1318,7 +1265,7 @@ again:
 			/* Establish new table */
 			pmd_populate(mm, pmd, (pte_t *) new);
 			/* Free old table with rcu, there might be a walker! */
-			page_table_free_rcu(tlb, table);
+			page_table_free_rcu(tlb, table, addr);
 			new = NULL;
 		}
 		spin_unlock(ptl);