gmap.c 63.4 KB
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/*
 *  KVM guest address space mapping code
 *
 *    Copyright IBM Corp. 2007, 2016
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/ksm.h>
#include <linux/mman.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/tlb.h>

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#define GMAP_SHADOW_FAKE_TABLE 1ULL

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/**
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 * gmap_alloc - allocate and initialize a guest address space
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 * @mm: pointer to the parent mm_struct
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 * @limit: maximum address of the gmap address space
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 *
 * Returns a guest address space structure.
 */
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static struct gmap *gmap_alloc(unsigned long limit)
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{
	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);
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	INIT_LIST_HEAD(&gmap->children);
	INIT_LIST_HEAD(&gmap->pt_list);
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	INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
	INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
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	INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC);
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	spin_lock_init(&gmap->guest_table_lock);
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	spin_lock_init(&gmap->shadow_lock);
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	atomic_set(&gmap->ref_count, 1);
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	page = alloc_pages(GFP_KERNEL, 2);
	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, etype);
	gmap->table = table;
	gmap->asce = atype | _ASCE_TABLE_LENGTH |
		_ASCE_USER_BITS | __pa(table);
	gmap->asce_end = limit;
	return gmap;

out_free:
	kfree(gmap);
out:
	return NULL;
}
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/**
 * gmap_create - create 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_create(struct mm_struct *mm, unsigned long limit)
{
	struct gmap *gmap;
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	unsigned long gmap_asce;
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	gmap = gmap_alloc(limit);
	if (!gmap)
		return NULL;
	gmap->mm = mm;
	spin_lock(&mm->context.gmap_lock);
	list_add_rcu(&gmap->list, &mm->context.gmap_list);
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	if (list_is_singular(&mm->context.gmap_list))
		gmap_asce = gmap->asce;
	else
		gmap_asce = -1UL;
	WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
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	spin_unlock(&mm->context.gmap_lock);
	return gmap;
}
EXPORT_SYMBOL_GPL(gmap_create);
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static void gmap_flush_tlb(struct gmap *gmap)
{
	if (MACHINE_HAS_IDTE)
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		__tlb_flush_idte(gmap->asce);
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	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);
}

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static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
{
	struct gmap_rmap *rmap, *rnext, *head;
	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];
			head = radix_tree_delete(root, index);
			gmap_for_each_rmap_safe(rmap, rnext, head)
				kfree(rmap);
		}
	} while (nr > 0);
}

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/**
 * gmap_free - free a guest address space
 * @gmap: pointer to the guest address space structure
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 *
 * No locks required. There are no references to this gmap anymore.
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 */
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static void gmap_free(struct gmap *gmap)
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{
	struct page *page, *next;

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	/* Flush tlb of all gmaps (if not already done for shadows) */
	if (!(gmap_is_shadow(gmap) && gmap->removed))
		gmap_flush_tlb(gmap);
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	/* Free all segment & region tables. */
	list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
		__free_pages(page, 2);
	gmap_radix_tree_free(&gmap->guest_to_host);
	gmap_radix_tree_free(&gmap->host_to_guest);
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	/* Free additional data for a shadow gmap */
	if (gmap_is_shadow(gmap)) {
		/* Free all page tables. */
		list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
			page_table_free_pgste(page);
		gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
		/* Release reference to the parent */
		gmap_put(gmap->parent);
	}

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	kfree(gmap);
}
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/**
 * gmap_get - increase reference counter for guest address space
 * @gmap: pointer to the guest address space structure
 *
 * Returns the gmap pointer
 */
struct gmap *gmap_get(struct gmap *gmap)
{
	atomic_inc(&gmap->ref_count);
	return gmap;
}
EXPORT_SYMBOL_GPL(gmap_get);

/**
 * gmap_put - decrease reference counter for guest address space
 * @gmap: pointer to the guest address space structure
 *
 * If the reference counter reaches zero the guest address space is freed.
 */
void gmap_put(struct gmap *gmap)
{
	if (atomic_dec_return(&gmap->ref_count) == 0)
		gmap_free(gmap);
}
EXPORT_SYMBOL_GPL(gmap_put);

/**
 * gmap_remove - remove a guest address space but do not free it yet
 * @gmap: pointer to the guest address space structure
 */
void gmap_remove(struct gmap *gmap)
{
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	struct gmap *sg, *next;
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	unsigned long gmap_asce;
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	/* Remove all shadow gmaps linked to this gmap */
	if (!list_empty(&gmap->children)) {
		spin_lock(&gmap->shadow_lock);
		list_for_each_entry_safe(sg, next, &gmap->children, list) {
			list_del(&sg->list);
			gmap_put(sg);
		}
		spin_unlock(&gmap->shadow_lock);
	}
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	/* Remove gmap from the pre-mm list */
	spin_lock(&gmap->mm->context.gmap_lock);
	list_del_rcu(&gmap->list);
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	if (list_empty(&gmap->mm->context.gmap_list))
		gmap_asce = 0;
	else if (list_is_singular(&gmap->mm->context.gmap_list))
		gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
					     struct gmap, list)->asce;
	else
		gmap_asce = -1UL;
	WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
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	spin_unlock(&gmap->mm->context.gmap_lock);
	synchronize_rcu();
	/* Put reference */
	gmap_put(gmap);
}
EXPORT_SYMBOL_GPL(gmap_remove);
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/**
 * gmap_enable - switch primary space to the guest address space
 * @gmap: pointer to the guest address space structure
 */
void gmap_enable(struct gmap *gmap)
{
	S390_lowcore.gmap = (unsigned long) gmap;
}
EXPORT_SYMBOL_GPL(gmap_enable);

/**
 * gmap_disable - switch back to the standard primary address space
 * @gmap: pointer to the guest address space structure
 */
void gmap_disable(struct gmap *gmap)
{
	S390_lowcore.gmap = 0UL;
}
EXPORT_SYMBOL_GPL(gmap_disable);

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/**
 * gmap_get_enabled - get a pointer to the currently enabled gmap
 *
 * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
 */
struct gmap *gmap_get_enabled(void)
{
	return (struct gmap *) S390_lowcore.gmap;
}
EXPORT_SYMBOL_GPL(gmap_get_enabled);

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/*
 * 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, unsigned long gaddr)
{
	struct page *page;
	unsigned long *new;

	/* since we dont free the gmap table until gmap_free we can unlock */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	new = (unsigned long *) page_to_phys(page);
	crst_table_init(new, init);
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	spin_lock(&gmap->guest_table_lock);
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	if (*table & _REGION_ENTRY_INVALID) {
		list_add(&page->lru, &gmap->crst_list);
		*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
			(*table & _REGION_ENTRY_TYPE_MASK);
		page->index = gaddr;
		page = NULL;
	}
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	spin_unlock(&gmap->guest_table_lock);
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	if (page)
		__free_pages(page, 2);
	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, mask;

	offset = (unsigned long) entry / sizeof(unsigned long);
	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
	mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
	page = virt_to_page((void *)((unsigned long) entry & mask));
	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;

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	BUG_ON(gmap_is_shadow(gmap));
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	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
 * @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 off;
	int flush;

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	BUG_ON(gmap_is_shadow(gmap));
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	if ((to | len) & (PMD_SIZE - 1))
		return -EINVAL;
	if (len == 0 || to + len < to)
		return -EINVAL;

	flush = 0;
	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;
}
EXPORT_SYMBOL_GPL(gmap_unmap_segment);

/**
 * gmap_map_segment - map a segment to the guest address space
 * @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 off;
	int flush;

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	BUG_ON(gmap_is_shadow(gmap));
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	if ((from | to | len) & (PMD_SIZE - 1))
		return -EINVAL;
	if (len == 0 || from + len < from || to + len < to ||
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	    from + len - 1 > TASK_MAX_SIZE || to + len - 1 > gmap->asce_end)
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		return -EINVAL;

	flush = 0;
	down_write(&gmap->mm->mmap_sem);
	for (off = 0; off < len; off += PMD_SIZE) {
		/* 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;
	}
	up_write(&gmap->mm->mmap_sem);
	if (flush)
		gmap_flush_tlb(gmap);
	if (off >= len)
		return 0;
	gmap_unmap_segment(gmap, to, len);
	return -ENOMEM;
}
EXPORT_SYMBOL_GPL(gmap_map_segment);

/**
 * __gmap_translate - translate a guest address to a user space 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.
 * The mmap_sem of the mm that belongs to the address space must be held
 * when this function gets called.
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 *
 * Note: Can also be called for shadow gmaps.
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 */
unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long vmaddr;

	vmaddr = (unsigned long)
		radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
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	/* Note: guest_to_host is empty for a shadow gmap */
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	return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
}
EXPORT_SYMBOL_GPL(__gmap_translate);

/**
 * gmap_translate - translate a guest address to a user space 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(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long rc;

	down_read(&gmap->mm->mmap_sem);
	rc = __gmap_translate(gmap, gaddr);
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_translate);

/**
 * 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
 */
void gmap_unlink(struct mm_struct *mm, unsigned long *table,
		 unsigned long vmaddr)
{
	struct gmap *gmap;
	int flush;

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	rcu_read_lock();
	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
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		flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
		if (flush)
			gmap_flush_tlb(gmap);
	}
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	rcu_read_unlock();
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}

/**
 * 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)
{
	struct mm_struct *mm;
	unsigned long *table;
	spinlock_t *ptl;
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	int rc;

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	BUG_ON(gmap_is_shadow(gmap));
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	/* 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 & 0xffe0000000000000UL))
			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 & 0xfffffc0000000000UL))
			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 & 0xffffffff80000000UL))
			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);
	VM_BUG_ON(pgd_none(*pgd));
	pud = pud_offset(pgd, vmaddr);
	VM_BUG_ON(pud_none(*pud));
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	/* large puds cannot yet be handled */
	if (pud_large(*pud))
		return -EFAULT;
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	pmd = pmd_offset(pud, vmaddr);
	VM_BUG_ON(pmd_none(*pmd));
	/* large pmds cannot yet be handled */
	if (pmd_large(*pmd))
		return -EFAULT;
	/* Link gmap segment table entry location to page table. */
	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;
}

/**
 * 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.
 */
int gmap_fault(struct gmap *gmap, unsigned long gaddr,
	       unsigned int fault_flags)
{
	unsigned long vmaddr;
	int rc;
	bool unlocked;

	down_read(&gmap->mm->mmap_sem);

retry:
	unlocked = false;
	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,
			     &unlocked)) {
		rc = -EFAULT;
		goto out_up;
	}
	/*
	 * In the case that fixup_user_fault unlocked the mmap_sem during
	 * faultin redo __gmap_translate to not race with a map/unmap_segment.
	 */
	if (unlocked)
		goto retry;

	rc = __gmap_link(gmap, gaddr, vmaddr);
out_up:
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_fault);

/*
 * this function is assumed to be called with mmap_sem held
 */
void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
{
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;

	/* Find the vm address for the guest address */
	vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
						   gaddr >> PMD_SHIFT);
	if (vmaddr) {
		vmaddr |= gaddr & ~PMD_MASK;
		/* Get pointer to the page table entry */
		ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
		if (likely(ptep))
			ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
		pte_unmap_unlock(ptep, ptl);
	}
}
EXPORT_SYMBOL_GPL(__gmap_zap);

void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
{
	unsigned long gaddr, vmaddr, size;
	struct vm_area_struct *vma;

	down_read(&gmap->mm->mmap_sem);
	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;
		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);
}
EXPORT_SYMBOL_GPL(gmap_discard);

static LIST_HEAD(gmap_notifier_list);
static DEFINE_SPINLOCK(gmap_notifier_lock);

/**
700
 * gmap_register_pte_notifier - register a pte invalidation callback
701 702
 * @nb: pointer to the gmap notifier block
 */
703
void gmap_register_pte_notifier(struct gmap_notifier *nb)
704 705
{
	spin_lock(&gmap_notifier_lock);
706
	list_add_rcu(&nb->list, &gmap_notifier_list);
707 708
	spin_unlock(&gmap_notifier_lock);
}
709
EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
710 711

/**
712
 * gmap_unregister_pte_notifier - remove a pte invalidation callback
713 714
 * @nb: pointer to the gmap notifier block
 */
715
void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
716 717
{
	spin_lock(&gmap_notifier_lock);
718
	list_del_rcu(&nb->list);
719
	spin_unlock(&gmap_notifier_lock);
720
	synchronize_rcu();
721
}
722
EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
723

724 725 726 727 728 729 730 731 732 733 734 735 736 737 738
/**
 * gmap_call_notifier - call all registered invalidation callbacks
 * @gmap: pointer to guest mapping meta data structure
 * @start: start virtual address in the guest address space
 * @end: end virtual address in the guest address space
 */
static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
			       unsigned long end)
{
	struct gmap_notifier *nb;

	list_for_each_entry(nb, &gmap_notifier_list, list)
		nb->notifier_call(gmap, start, end);
}

739
/**
740 741 742
 * gmap_table_walk - walk the gmap page tables
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
743 744 745 746 747 748 749 750 751 752 753
 * @level: page table level to stop at
 *
 * Returns a table entry pointer for the given guest address and @level
 * @level=0 : returns a pointer to a page table table entry (or NULL)
 * @level=1 : returns a pointer to a segment table entry (or NULL)
 * @level=2 : returns a pointer to a region-3 table entry (or NULL)
 * @level=3 : returns a pointer to a region-2 table entry (or NULL)
 * @level=4 : returns a pointer to a region-1 table entry (or NULL)
 *
 * Returns NULL if the gmap page tables could not be walked to the
 * requested level.
754
 *
755
 * Note: Can also be called for shadow gmaps.
756 757
 */
static inline unsigned long *gmap_table_walk(struct gmap *gmap,
758
					     unsigned long gaddr, int level)
759 760 761
{
	unsigned long *table;

762 763 764 765 766 767
	if ((gmap->asce & _ASCE_TYPE_MASK) + 4 < (level * 4))
		return NULL;
	if (gmap_is_shadow(gmap) && gmap->removed)
		return NULL;
	if (gaddr & (-1UL << (31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11)))
		return NULL;
768 769 770 771
	table = gmap->table;
	switch (gmap->asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_REGION1:
		table += (gaddr >> 53) & 0x7ff;
772 773
		if (level == 4)
			break;
774 775 776 777 778 779
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION2:
		table += (gaddr >> 42) & 0x7ff;
780 781
		if (level == 3)
			break;
782 783 784 785 786 787
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION3:
		table += (gaddr >> 31) & 0x7ff;
788 789
		if (level == 2)
			break;
790 791 792 793 794 795
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_SEGMENT:
		table += (gaddr >> 20) & 0x7ff;
796 797 798 799 800 801
		if (level == 1)
			break;
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
		table += (gaddr >> 12) & 0xff;
802 803 804 805 806 807 808 809 810 811 812 813
	}
	return table;
}

/**
 * gmap_pte_op_walk - walk the gmap page table, get the page table lock
 *		      and return the pte pointer
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @ptl: pointer to the spinlock pointer
 *
 * Returns a pointer to the locked pte for a guest address, or NULL
814 815
 *
 * Note: Can also be called for shadow gmaps.
816 817 818 819 820 821
 */
static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
			       spinlock_t **ptl)
{
	unsigned long *table;

822 823
	if (gmap_is_shadow(gmap))
		spin_lock(&gmap->guest_table_lock);
824
	/* Walk the gmap page table, lock and get pte pointer */
825 826 827 828
	table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
	if (!table || *table & _SEGMENT_ENTRY_INVALID) {
		if (gmap_is_shadow(gmap))
			spin_unlock(&gmap->guest_table_lock);
829
		return NULL;
830 831 832 833 834
	}
	if (gmap_is_shadow(gmap)) {
		*ptl = &gmap->guest_table_lock;
		return pte_offset_map((pmd_t *) table, gaddr);
	}
835 836 837 838 839 840 841 842
	return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
}

/**
 * gmap_pte_op_fixup - force a page in and connect the gmap page table
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @vmaddr: address in the host process address space
843
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
844 845 846 847 848 849
 *
 * Returns 0 if the caller can retry __gmap_translate (might fail again),
 * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
 * up or connecting the gmap page table.
 */
static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
850
			     unsigned long vmaddr, int prot)
851 852
{
	struct mm_struct *mm = gmap->mm;
853
	unsigned int fault_flags;
854 855
	bool unlocked = false;

856
	BUG_ON(gmap_is_shadow(gmap));
857 858
	fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
	if (fixup_user_fault(current, mm, vmaddr, fault_flags, &unlocked))
859 860 861 862 863 864
		return -EFAULT;
	if (unlocked)
		/* lost mmap_sem, caller has to retry __gmap_translate */
		return 0;
	/* Connect the page tables */
	return __gmap_link(gmap, gaddr, vmaddr);
865 866 867
}

/**
868 869 870 871 872 873 874 875
 * gmap_pte_op_end - release the page table lock
 * @ptl: pointer to the spinlock pointer
 */
static void gmap_pte_op_end(spinlock_t *ptl)
{
	spin_unlock(ptl);
}

876 877
/*
 * gmap_protect_range - remove access rights to memory and set pgste bits
878 879 880
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
881 882 883 884 885 886 887
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
 * @bits: pgste notification bits to set
 *
 * Returns 0 if successfully protected, -ENOMEM if out of memory and
 * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
 *
 * Called with sg->mm->mmap_sem in read.
888
 *
889
 * Note: Can also be called for shadow gmaps.
890
 */
891 892
static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
			      unsigned long len, int prot, unsigned long bits)
893
{
894
	unsigned long vmaddr;
895 896
	spinlock_t *ptl;
	pte_t *ptep;
897 898 899 900 901 902 903 904 905 906 907 908 909
	int rc;

	while (len) {
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
		if (ptep) {
			rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, bits);
			gmap_pte_op_end(ptl);
		}
		if (rc) {
			vmaddr = __gmap_translate(gmap, gaddr);
			if (IS_ERR_VALUE(vmaddr))
				return vmaddr;
910
			rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
911 912 913 914 915 916 917 918 919
			if (rc)
				return rc;
			continue;
		}
		gaddr += PAGE_SIZE;
		len -= PAGE_SIZE;
	}
	return 0;
}
920

921 922 923
/**
 * gmap_mprotect_notify - change access rights for a range of ptes and
 *                        call the notifier if any pte changes again
924 925 926
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
927
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
928
 *
929 930 931 932 933
 * Returns 0 if for each page in the given range a gmap mapping exists,
 * the new access rights could be set and the notifier could be armed.
 * If the gmap mapping is missing for one or more pages -EFAULT is
 * returned. If no memory could be allocated -ENOMEM is returned.
 * This function establishes missing page table entries.
934
 */
935 936
int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
			 unsigned long len, int prot)
937
{
938
	int rc;
939

940
	if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
941
		return -EINVAL;
942
	if (!MACHINE_HAS_ESOP && prot == PROT_READ)
943 944
		return -EINVAL;
	down_read(&gmap->mm->mmap_sem);
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
	rc = gmap_protect_range(gmap, gaddr, len, prot, PGSTE_IN_BIT);
	up_read(&gmap->mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_mprotect_notify);

/**
 * gmap_read_table - get an unsigned long value from a guest page table using
 *                   absolute addressing, without marking the page referenced.
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @val: pointer to the unsigned long value to return
 *
 * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
 * if reading using the virtual address failed.
 *
 * Called with gmap->mm->mmap_sem in read.
 */
int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
{
	unsigned long address, vmaddr;
	spinlock_t *ptl;
	pte_t *ptep, pte;
	int rc;

	while (1) {
971 972 973
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
		if (ptep) {
974 975 976 977 978 979 980 981 982
			pte = *ptep;
			if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
				address = pte_val(pte) & PAGE_MASK;
				address += gaddr & ~PAGE_MASK;
				*val = *(unsigned long *) address;
				pte_val(*ptep) |= _PAGE_YOUNG;
				/* Do *NOT* clear the _PAGE_INVALID bit! */
				rc = 0;
			}
983
			gmap_pte_op_end(ptl);
984
		}
985 986 987 988 989
		if (!rc)
			break;
		vmaddr = __gmap_translate(gmap, gaddr);
		if (IS_ERR_VALUE(vmaddr)) {
			rc = vmaddr;
990 991
			break;
		}
992
		rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
993 994 995 996 997
		if (rc)
			break;
	}
	return rc;
}
998
EXPORT_SYMBOL_GPL(gmap_read_table);
999 1000

/**
1001 1002 1003 1004
 * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
 * @sg: pointer to the shadow guest address space structure
 * @vmaddr: vm address associated with the rmap
 * @rmap: pointer to the rmap structure
1005
 *
1006
 * Called with the sg->guest_table_lock
1007
 */
1008 1009
static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
				    struct gmap_rmap *rmap)
1010
{
1011
	void **slot;
1012

1013 1014 1015 1016 1017
	BUG_ON(!gmap_is_shadow(sg));
	slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
	if (slot) {
		rmap->next = radix_tree_deref_slot_protected(slot,
							&sg->guest_table_lock);
1018
		radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
	} else {
		rmap->next = NULL;
		radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
				  rmap);
	}
}

/**
 * gmap_protect_rmap - modify access rights to memory and create an rmap
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow gmap
 * @paddr: address in the parent guest address space
 * @len: length of the memory area to protect
 * @prot: indicates access rights: none, read-only or read-write
 *
 * Returns 0 if successfully protected and the rmap was created, -ENOMEM
 * if out of memory and -EFAULT if paddr is invalid.
 */
static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
			     unsigned long paddr, unsigned long len, int prot)
{
	struct gmap *parent;
	struct gmap_rmap *rmap;
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	parent = sg->parent;
	while (len) {
		vmaddr = __gmap_translate(parent, paddr);
		if (IS_ERR_VALUE(vmaddr))
			return vmaddr;
		rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
		if (!rmap)
			return -ENOMEM;
		rmap->raddr = raddr;
		rc = radix_tree_preload(GFP_KERNEL);
1058
		if (rc) {
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
			kfree(rmap);
			return rc;
		}
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(parent, paddr, &ptl);
		if (ptep) {
			spin_lock(&sg->guest_table_lock);
			rc = ptep_force_prot(parent->mm, paddr, ptep, prot,
					     PGSTE_VSIE_BIT);
			if (!rc)
				gmap_insert_rmap(sg, vmaddr, rmap);
			spin_unlock(&sg->guest_table_lock);
			gmap_pte_op_end(ptl);
		}
		radix_tree_preload_end();
		if (rc) {
			kfree(rmap);
1076
			rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
1077
			if (rc)
1078
				return rc;
1079 1080
			continue;
		}
1081
		paddr += PAGE_SIZE;
1082
		len -= PAGE_SIZE;
1083
	}
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161
	return 0;
}

#define _SHADOW_RMAP_MASK	0x7
#define _SHADOW_RMAP_REGION1	0x5
#define _SHADOW_RMAP_REGION2	0x4
#define _SHADOW_RMAP_REGION3	0x3
#define _SHADOW_RMAP_SEGMENT	0x2
#define _SHADOW_RMAP_PGTABLE	0x1

/**
 * gmap_idte_one - invalidate a single region or segment table entry
 * @asce: region or segment table *origin* + table-type bits
 * @vaddr: virtual address to identify the table entry to flush
 *
 * The invalid bit of a single region or segment table entry is set
 * and the associated TLB entries depending on the entry are flushed.
 * The table-type of the @asce identifies the portion of the @vaddr
 * that is used as the invalidation index.
 */
static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
{
	asm volatile(
		"	.insn	rrf,0xb98e0000,%0,%1,0,0"
		: : "a" (asce), "a" (vaddr) : "cc", "memory");
}

/**
 * gmap_unshadow_page - remove a page from a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
{
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
	if (!table || *table & _PAGE_INVALID)
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 12) - 1);
	ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
}

/**
 * __gmap_unshadow_pgt - remove all entries from a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @pgt: pointer to the start of a shadow page table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
				unsigned long *pgt)
{
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	for (i = 0; i < 256; i++, raddr += 1UL << 12)
		pgt[i] = _PAGE_INVALID;
}

/**
 * gmap_unshadow_pgt - remove a shadow page table from a segment entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
{
	unsigned long sto, *ste, *pgt;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
1162
	if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 20) - 1);
	sto = (unsigned long) (ste - ((raddr >> 20) & 0x7ff));
	gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
	pgt = (unsigned long *)(*ste & _SEGMENT_ENTRY_ORIGIN);
	*ste = _SEGMENT_ENTRY_EMPTY;
	__gmap_unshadow_pgt(sg, raddr, pgt);
	/* Free page table */
	page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
	list_del(&page->lru);
	page_table_free_pgste(page);
}

/**
 * __gmap_unshadow_sgt - remove all entries from a shadow segment table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @sgt: pointer to the start of a shadow segment table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
				unsigned long *sgt)
{
	unsigned long asce, *pgt;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) sgt | _ASCE_TYPE_SEGMENT;
	for (i = 0; i < 2048; i++, raddr += 1UL << 20) {
1194
		if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219
			continue;
		pgt = (unsigned long *)(sgt[i] & _REGION_ENTRY_ORIGIN);
		sgt[i] = _SEGMENT_ENTRY_EMPTY;
		__gmap_unshadow_pgt(sg, raddr, pgt);
		/* Free page table */
		page = pfn_to_page(__pa(pgt) >> PAGE_SHIFT);
		list_del(&page->lru);
		page_table_free_pgste(page);
	}
}

/**
 * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the shadow->guest_table_lock
 */
static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
{
	unsigned long r3o, *r3e, *sgt;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
1220
	if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 31) - 1);
	r3o = (unsigned long) (r3e - ((raddr >> 31) & 0x7ff));
	gmap_idte_one(r3o | _ASCE_TYPE_REGION3, raddr);
	sgt = (unsigned long *)(*r3e & _REGION_ENTRY_ORIGIN);
	*r3e = _REGION3_ENTRY_EMPTY;
	__gmap_unshadow_sgt(sg, raddr, sgt);
	/* Free segment table */
	page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: address in the shadow guest address space
 * @r3t: pointer to the start of a shadow region-3 table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
				unsigned long *r3t)
{
	unsigned long asce, *sgt;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r3t | _ASCE_TYPE_REGION3;
	for (i = 0; i < 2048; i++, raddr += 1UL << 31) {
1252
		if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277
			continue;
		sgt = (unsigned long *)(r3t[i] & _REGION_ENTRY_ORIGIN);
		r3t[i] = _REGION3_ENTRY_EMPTY;
		__gmap_unshadow_sgt(sg, raddr, sgt);
		/* Free segment table */
		page = pfn_to_page(__pa(sgt) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
{
	unsigned long r2o, *r2e, *r3t;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
1278
	if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 42) - 1);
	r2o = (unsigned long) (r2e - ((raddr >> 42) & 0x7ff));
	gmap_idte_one(r2o | _ASCE_TYPE_REGION2, raddr);
	r3t = (unsigned long *)(*r2e & _REGION_ENTRY_ORIGIN);
	*r2e = _REGION2_ENTRY_EMPTY;
	__gmap_unshadow_r3t(sg, raddr, r3t);
	/* Free region 3 table */
	page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @r2t: pointer to the start of a shadow region-2 table
 *
 * Called with the sg->guest_table_lock
 */
static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
				unsigned long *r2t)
{
	unsigned long asce, *r3t;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r2t | _ASCE_TYPE_REGION2;
	for (i = 0; i < 2048; i++, raddr += 1UL << 42) {
1310
		if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335
			continue;
		r3t = (unsigned long *)(r2t[i] & _REGION_ENTRY_ORIGIN);
		r2t[i] = _REGION2_ENTRY_EMPTY;
		__gmap_unshadow_r3t(sg, raddr, r3t);
		/* Free region 3 table */
		page = pfn_to_page(__pa(r3t) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 *
 * Called with the sg->guest_table_lock
 */
static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
{
	unsigned long r1o, *r1e, *r2t;
	struct page *page;

	BUG_ON(!gmap_is_shadow(sg));
	r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
1336
	if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367
		return;
	gmap_call_notifier(sg, raddr, raddr + (1UL << 53) - 1);
	r1o = (unsigned long) (r1e - ((raddr >> 53) & 0x7ff));
	gmap_idte_one(r1o | _ASCE_TYPE_REGION1, raddr);
	r2t = (unsigned long *)(*r1e & _REGION_ENTRY_ORIGIN);
	*r1e = _REGION1_ENTRY_EMPTY;
	__gmap_unshadow_r2t(sg, raddr, r2t);
	/* Free region 2 table */
	page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
	list_del(&page->lru);
	__free_pages(page, 2);
}

/**
 * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
 * @sg: pointer to the shadow guest address space structure
 * @raddr: rmap address in the shadow guest address space
 * @r1t: pointer to the start of a shadow region-1 table
 *
 * Called with the shadow->guest_table_lock
 */
static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
				unsigned long *r1t)
{
	unsigned long asce, *r2t;
	struct page *page;
	int i;

	BUG_ON(!gmap_is_shadow(sg));
	asce = (unsigned long) r1t | _ASCE_TYPE_REGION1;
	for (i = 0; i < 2048; i++, raddr += 1UL << 53) {
1368
		if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396
			continue;
		r2t = (unsigned long *)(r1t[i] & _REGION_ENTRY_ORIGIN);
		__gmap_unshadow_r2t(sg, raddr, r2t);
		/* Clear entry and flush translation r1t -> r2t */
		gmap_idte_one(asce, raddr);
		r1t[i] = _REGION1_ENTRY_EMPTY;
		/* Free region 2 table */
		page = pfn_to_page(__pa(r2t) >> PAGE_SHIFT);
		list_del(&page->lru);
		__free_pages(page, 2);
	}
}

/**
 * gmap_unshadow - remove a shadow page table completely
 * @sg: pointer to the shadow guest address space structure
 *
 * Called with sg->guest_table_lock
 */
static void gmap_unshadow(struct gmap *sg)
{
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	if (sg->removed)
		return;
	sg->removed = 1;
	gmap_call_notifier(sg, 0, -1UL);
1397
	gmap_flush_tlb(sg);
1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
	table = (unsigned long *)(sg->asce & _ASCE_ORIGIN);
	switch (sg->asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_REGION1:
		__gmap_unshadow_r1t(sg, 0, table);
		break;
	case _ASCE_TYPE_REGION2:
		__gmap_unshadow_r2t(sg, 0, table);
		break;
	case _ASCE_TYPE_REGION3:
		__gmap_unshadow_r3t(sg, 0, table);
		break;
	case _ASCE_TYPE_SEGMENT:
		__gmap_unshadow_sgt(sg, 0, table);
		break;
	}
}

/**
 * gmap_find_shadow - find a specific asce in the list of shadow tables
 * @parent: pointer to the parent gmap
 * @asce: ASCE for which the shadow table is created
1419
 * @edat_level: edat level to be used for the shadow translation
1420 1421
 *
 * Returns the pointer to a gmap if a shadow table with the given asce is
1422 1423
 * already available, ERR_PTR(-EAGAIN) if another one is just being created,
 * otherwise NULL
1424
 */
1425 1426
static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
				     int edat_level)
1427 1428 1429 1430
{
	struct gmap *sg;

	list_for_each_entry(sg, &parent->children, list) {
1431 1432
		if (sg->orig_asce != asce || sg->edat_level != edat_level ||
		    sg->removed)
1433
			continue;
1434 1435
		if (!sg->initialized)
			return ERR_PTR(-EAGAIN);
1436 1437 1438 1439 1440 1441
		atomic_inc(&sg->ref_count);
		return sg;
	}
	return NULL;
}

1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461
/**
 * gmap_shadow_valid - check if a shadow guest address space matches the
 *                     given properties and is still valid
 * @sg: pointer to the shadow guest address space structure
 * @asce: ASCE for which the shadow table is requested
 * @edat_level: edat level to be used for the shadow translation
 *
 * Returns 1 if the gmap shadow is still valid and matches the given
 * properties, the caller can continue using it. Returns 0 otherwise, the
 * caller has to request a new shadow gmap in this case.
 *
 */
int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
{
	if (sg->removed)
		return 0;
	return sg->orig_asce == asce && sg->edat_level == edat_level;
}
EXPORT_SYMBOL_GPL(gmap_shadow_valid);

1462 1463 1464 1465
/**
 * gmap_shadow - create/find a shadow guest address space
 * @parent: pointer to the parent gmap
 * @asce: ASCE for which the shadow table is created
1466
 * @edat_level: edat level to be used for the shadow translation
1467 1468 1469 1470 1471 1472
 *
 * The pages of the top level page table referred by the asce parameter
 * will be set to read-only and marked in the PGSTEs of the kvm process.
 * The shadow table will be removed automatically on any change to the
 * PTE mapping for the source table.
 *
1473 1474 1475
 * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
 * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
 * parent gmap table could not be protected.
1476
 */
1477 1478
struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
			 int edat_level)
1479 1480 1481 1482 1483 1484 1485
{
	struct gmap *sg, *new;
	unsigned long limit;
	int rc;

	BUG_ON(gmap_is_shadow(parent));
	spin_lock(&parent->shadow_lock);
1486
	sg = gmap_find_shadow(parent, asce, edat_level);
1487 1488 1489 1490 1491
	spin_unlock(&parent->shadow_lock);
	if (sg)
		return sg;
	/* Create a new shadow gmap */
	limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
1492 1493
	if (asce & _ASCE_REAL_SPACE)
		limit = -1UL;
1494 1495
	new = gmap_alloc(limit);
	if (!new)
1496
		return ERR_PTR(-ENOMEM);
1497 1498 1499
	new->mm = parent->mm;
	new->parent = gmap_get(parent);
	new->orig_asce = asce;
1500
	new->edat_level = edat_level;
1501 1502 1503
	new->initialized = false;
	spin_lock(&parent->shadow_lock);
	/* Recheck if another CPU created the same shadow */
1504
	sg = gmap_find_shadow(parent, asce, edat_level);
1505 1506 1507 1508 1509
	if (sg) {
		spin_unlock(&parent->shadow_lock);
		gmap_free(new);
		return sg;
	}
1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
	if (asce & _ASCE_REAL_SPACE) {
		/* only allow one real-space gmap shadow */
		list_for_each_entry(sg, &parent->children, list) {
			if (sg->orig_asce & _ASCE_REAL_SPACE) {
				spin_lock(&sg->guest_table_lock);
				gmap_unshadow(sg);
				spin_unlock(&sg->guest_table_lock);
				list_del(&sg->list);
				gmap_put(sg);
				break;
			}
		}
	}
1523 1524
	atomic_set(&new->ref_count, 2);
	list_add(&new->list, &parent->children);
1525 1526 1527 1528 1529 1530
	if (asce & _ASCE_REAL_SPACE) {
		/* nothing to protect, return right away */
		new->initialized = true;
		spin_unlock(&parent->shadow_lock);
		return new;
	}
1531 1532
	spin_unlock(&parent->shadow_lock);
	/* protect after insertion, so it will get properly invalidated */
1533 1534 1535 1536 1537
	down_read(&parent->mm->mmap_sem);
	rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
				((asce & _ASCE_TABLE_LENGTH) + 1) * 4096,
				PROT_READ, PGSTE_VSIE_BIT);
	up_read(&parent->mm->mmap_sem);
1538 1539
	spin_lock(&parent->shadow_lock);
	new->initialized = true;
1540
	if (rc) {
1541
		list_del(&new->list);
1542
		gmap_free(new);
1543 1544 1545 1546
		new = ERR_PTR(rc);
	}
	spin_unlock(&parent->shadow_lock);
	return new;
1547 1548 1549 1550 1551 1552 1553 1554
}
EXPORT_SYMBOL_GPL(gmap_shadow);

/**
 * gmap_shadow_r2t - create an empty shadow region 2 table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @r2t: parent gmap address of the region 2 table to get shadowed
1555
 * @fake: r2t references contiguous guest memory block, not a r2t
1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567
 *
 * The r2t parameter specifies the address of the source table. The
 * four pages of the source table are made read-only in the parent gmap
 * address space. A write to the source table area @r2t will automatically
 * remove the shadow r2 table and all of its decendents.
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
1568 1569
int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
		    int fake)
1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_r2t, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow region second table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = r2t & _REGION_ENTRY_ORIGIN;
1582 1583
	if (fake)
		page->index |= GMAP_SHADOW_FAKE_TABLE;
1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594
	s_r2t = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1595 1596 1597
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1598 1599
	}
	crst_table_init(s_r2t, _REGION2_ENTRY_EMPTY);
1600 1601 1602
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_r2t | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
1603 1604
	if (sg->edat_level >= 1)
		*table |= (r2t & _REGION_ENTRY_PROTECT);
1605
	list_add(&page->lru, &sg->crst_list);
1606 1607 1608 1609 1610 1611
	if (fake) {
		/* nothing to protect for fake tables */
		*table &= ~_REGION_ENTRY_INVALID;
		spin_unlock(&sg->guest_table_lock);
		return 0;
	}
1612 1613 1614 1615 1616 1617 1618
	spin_unlock(&sg->guest_table_lock);
	/* Make r2t read-only in parent gmap page table */
	raddr = (saddr & 0xffe0000000000000UL) | _SHADOW_RMAP_REGION1;
	origin = r2t & _REGION_ENTRY_ORIGIN;
	offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1619 1620 1621 1622 1623 1624 1625 1626 1627
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 4);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_r2t)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1628 1629
		gmap_unshadow_r2t(sg, raddr);
	}
1630
	spin_unlock(&sg->guest_table_lock);
1631 1632 1633 1634
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
1635 1636
	return rc;
}
1637 1638 1639 1640 1641 1642 1643
EXPORT_SYMBOL_GPL(gmap_shadow_r2t);

/**
 * gmap_shadow_r3t - create a shadow region 3 table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @r3t: parent gmap address of the region 3 table to get shadowed
1644
 * @fake: r3t references contiguous guest memory block, not a r3t
1645 1646 1647 1648 1649 1650 1651
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
1652 1653
int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
		    int fake)
1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_r3t, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow region second table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = r3t & _REGION_ENTRY_ORIGIN;
1666 1667
	if (fake)
		page->index |= GMAP_SHADOW_FAKE_TABLE;
1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678
	s_r3t = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1679 1680
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
1681 1682
	}
	crst_table_init(s_r3t, _REGION3_ENTRY_EMPTY);
1683 1684 1685
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_r3t | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
1686 1687
	if (sg->edat_level >= 1)
		*table |= (r3t & _REGION_ENTRY_PROTECT);
1688
	list_add(&page->lru, &sg->crst_list);
1689 1690 1691 1692 1693 1694
	if (fake) {
		/* nothing to protect for fake tables */
		*table &= ~_REGION_ENTRY_INVALID;
		spin_unlock(&sg->guest_table_lock);
		return 0;
	}
1695 1696 1697 1698 1699 1700 1701
	spin_unlock(&sg->guest_table_lock);
	/* Make r3t read-only in parent gmap page table */
	raddr = (saddr & 0xfffffc0000000000UL) | _SHADOW_RMAP_REGION2;
	origin = r3t & _REGION_ENTRY_ORIGIN;
	offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1702 1703 1704 1705 1706 1707 1708 1709 1710
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 3);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_r3t)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1711 1712
		gmap_unshadow_r3t(sg, raddr);
	}
1713
	spin_unlock(&sg->guest_table_lock);
1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_r3t);

/**
 * gmap_shadow_sgt - create a shadow segment table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @sgt: parent gmap address of the segment table to get shadowed
1727
 * @fake: sgt references contiguous guest memory block, not a sgt
1728 1729 1730 1731 1732 1733 1734
 *
 * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
1735 1736
int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
		    int fake)
1737 1738 1739 1740 1741 1742
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_sgt, *table;
	struct page *page;
	int rc;

1743
	BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
1744 1745 1746 1747 1748
	/* Allocate a shadow segment table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = sgt & _REGION_ENTRY_ORIGIN;
1749 1750
	if (fake)
		page->index |= GMAP_SHADOW_FAKE_TABLE;
1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761
	s_sgt = (unsigned long *) page_to_phys(page);
	/* Install shadow region second table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _REGION_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1762 1763 1764
	} else if (*table & _REGION_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1765 1766
	}
	crst_table_init(s_sgt, _SEGMENT_ENTRY_EMPTY);
1767 1768 1769
	/* mark as invalid as long as the parent table is not protected */
	*table = (unsigned long) s_sgt | _REGION_ENTRY_LENGTH |
		 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
1770 1771
	if (sg->edat_level >= 1)
		*table |= sgt & _REGION_ENTRY_PROTECT;
1772
	list_add(&page->lru, &sg->crst_list);
1773 1774 1775 1776 1777 1778
	if (fake) {
		/* nothing to protect for fake tables */
		*table &= ~_REGION_ENTRY_INVALID;
		spin_unlock(&sg->guest_table_lock);
		return 0;
	}
1779 1780 1781 1782 1783 1784 1785
	spin_unlock(&sg->guest_table_lock);
	/* Make sgt read-only in parent gmap page table */
	raddr = (saddr & 0xffffffff80000000UL) | _SHADOW_RMAP_REGION3;
	origin = sgt & _REGION_ENTRY_ORIGIN;
	offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * 4096;
	len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * 4096 - offset;
	rc = gmap_protect_rmap(sg, raddr, origin + offset, len, PROT_READ);
1786 1787 1788 1789 1790 1791 1792 1793 1794
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 2);
		if (!table || (*table & _REGION_ENTRY_ORIGIN) !=
			      (unsigned long) s_sgt)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_REGION_ENTRY_INVALID;
	} else {
1795 1796
		gmap_unshadow_sgt(sg, raddr);
	}
1797
	spin_unlock(&sg->guest_table_lock);
1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_sgt);

/**
 * gmap_shadow_lookup_pgtable - find a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: the address in the shadow aguest address space
 * @pgt: parent gmap address of the page table to get shadowed
 * @dat_protection: if the pgtable is marked as protected by dat
1812
 * @fake: pgt references contiguous guest memory block, not a pgtable
1813 1814 1815 1816 1817 1818 1819
 *
 * Returns 0 if the shadow page table was found and -EAGAIN if the page
 * table was not found.
 *
 * Called with sg->mm->mmap_sem in read.
 */
int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
1820 1821
			   unsigned long *pgt, int *dat_protection,
			   int *fake)
1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832
{
	unsigned long *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
		/* Shadow page tables are full pages (pte+pgste) */
		page = pfn_to_page(*table >> PAGE_SHIFT);
1833
		*pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
1834
		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
1835
		*fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850
		rc = 0;
	} else  {
		rc = -EAGAIN;
	}
	spin_unlock(&sg->guest_table_lock);
	return rc;

}
EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);

/**
 * gmap_shadow_pgt - instantiate a shadow page table
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
 * @pgt: parent gmap address of the page table to get shadowed
1851
 * @fake: pgt references contiguous guest memory block, not a pgtable
1852 1853 1854 1855 1856 1857 1858
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory,
 * -EFAULT if an address in the parent gmap could not be resolved and
 *
 * Called with gmap->mm->mmap_sem in read
 */
1859 1860
int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
		    int fake)
1861 1862 1863 1864 1865 1866
{
	unsigned long raddr, origin;
	unsigned long *s_pgt, *table;
	struct page *page;
	int rc;

1867
	BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
1868 1869 1870 1871 1872
	/* Allocate a shadow page table */
	page = page_table_alloc_pgste(sg->mm);
	if (!page)
		return -ENOMEM;
	page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
1873 1874
	if (fake)
		page->index |= GMAP_SHADOW_FAKE_TABLE;
1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
	s_pgt = (unsigned long *) page_to_phys(page);
	/* Install shadow page table */
	spin_lock(&sg->guest_table_lock);
	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
	if (!table) {
		rc = -EAGAIN;		/* Race with unshadow */
		goto out_free;
	}
	if (!(*table & _SEGMENT_ENTRY_INVALID)) {
		rc = 0;			/* Already established */
		goto out_free;
1886 1887 1888
	} else if (*table & _SEGMENT_ENTRY_ORIGIN) {
		rc = -EAGAIN;		/* Race with shadow */
		goto out_free;
1889
	}
1890
	/* mark as invalid as long as the parent table is not protected */
1891
	*table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
1892
		 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
1893
	list_add(&page->lru, &sg->pt_list);
1894 1895 1896 1897 1898 1899
	if (fake) {
		/* nothing to protect for fake tables */
		*table &= ~_SEGMENT_ENTRY_INVALID;
		spin_unlock(&sg->guest_table_lock);
		return 0;
	}
1900 1901 1902 1903 1904
	spin_unlock(&sg->guest_table_lock);
	/* Make pgt read-only in parent gmap page table (not the pgste) */
	raddr = (saddr & 0xfffffffffff00000UL) | _SHADOW_RMAP_SEGMENT;
	origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
	rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE, PROT_READ);
1905 1906 1907 1908 1909 1910 1911 1912 1913
	spin_lock(&sg->guest_table_lock);
	if (!rc) {
		table = gmap_table_walk(sg, saddr, 1);
		if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) !=
			      (unsigned long) s_pgt)
			rc = -EAGAIN;		/* Race with unshadow */
		else
			*table &= ~_SEGMENT_ENTRY_INVALID;
	} else {
1914 1915
		gmap_unshadow_pgt(sg, raddr);
	}
1916
	spin_unlock(&sg->guest_table_lock);
1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	page_table_free_pgste(page);
	return rc;

}
EXPORT_SYMBOL_GPL(gmap_shadow_pgt);

/**
 * gmap_shadow_page - create a shadow page mapping
 * @sg: pointer to the shadow guest address space structure
 * @saddr: faulting address in the shadow gmap
1930
 * @pte: pte in parent gmap address space to get shadowed
1931 1932 1933 1934 1935 1936 1937
 *
 * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
 * shadow table structure is incomplete, -ENOMEM if out of memory and
 * -EFAULT if an address in the parent gmap could not be resolved.
 *
 * Called with sg->mm->mmap_sem in read.
 */
1938
int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
1939 1940 1941
{
	struct gmap *parent;
	struct gmap_rmap *rmap;
1942
	unsigned long vmaddr, paddr;
1943 1944
	spinlock_t *ptl;
	pte_t *sptep, *tptep;
1945
	int prot;
1946 1947 1948 1949
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	parent = sg->parent;
1950
	prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
1951 1952 1953 1954 1955 1956 1957

	rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
	if (!rmap)
		return -ENOMEM;
	rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;

	while (1) {
1958
		paddr = pte_val(pte) & PAGE_MASK;
1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978
		vmaddr = __gmap_translate(parent, paddr);
		if (IS_ERR_VALUE(vmaddr)) {
			rc = vmaddr;
			break;
		}
		rc = radix_tree_preload(GFP_KERNEL);
		if (rc)
			break;
		rc = -EAGAIN;
		sptep = gmap_pte_op_walk(parent, paddr, &ptl);
		if (sptep) {
			spin_lock(&sg->guest_table_lock);
			/* Get page table pointer */
			tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
			if (!tptep) {
				spin_unlock(&sg->guest_table_lock);
				gmap_pte_op_end(ptl);
				radix_tree_preload_end();
				break;
			}
1979
			rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991
			if (rc > 0) {
				/* Success and a new mapping */
				gmap_insert_rmap(sg, vmaddr, rmap);
				rmap = NULL;
				rc = 0;
			}
			gmap_pte_op_end(ptl);
			spin_unlock(&sg->guest_table_lock);
		}
		radix_tree_preload_end();
		if (!rc)
			break;
1992
		rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029
		if (rc)
			break;
	}
	kfree(rmap);
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_shadow_page);

/**
 * gmap_shadow_notify - handle notifications for shadow gmap
 *
 * Called with sg->parent->shadow_lock.
 */
static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
			       unsigned long offset, pte_t *pte)
{
	struct gmap_rmap *rmap, *rnext, *head;
	unsigned long gaddr, start, end, bits, raddr;
	unsigned long *table;

	BUG_ON(!gmap_is_shadow(sg));
	spin_lock(&sg->parent->guest_table_lock);
	table = radix_tree_lookup(&sg->parent->host_to_guest,
				  vmaddr >> PMD_SHIFT);
	gaddr = table ? __gmap_segment_gaddr(table) + offset : 0;
	spin_unlock(&sg->parent->guest_table_lock);
	if (!table)
		return;

	spin_lock(&sg->guest_table_lock);
	if (sg->removed) {
		spin_unlock(&sg->guest_table_lock);
		return;
	}
	/* Check for top level table */
	start = sg->orig_asce & _ASCE_ORIGIN;
	end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * 4096;
2030 2031
	if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
	    gaddr < end) {
2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064
		/* The complete shadow table has to go */
		gmap_unshadow(sg);
		spin_unlock(&sg->guest_table_lock);
		list_del(&sg->list);
		gmap_put(sg);
		return;
	}
	/* Remove the page table tree from on specific entry */
	head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> 12);
	gmap_for_each_rmap_safe(rmap, rnext, head) {
		bits = rmap->raddr & _SHADOW_RMAP_MASK;
		raddr = rmap->raddr ^ bits;
		switch (bits) {
		case _SHADOW_RMAP_REGION1:
			gmap_unshadow_r2t(sg, raddr);
			break;
		case _SHADOW_RMAP_REGION2:
			gmap_unshadow_r3t(sg, raddr);
			break;
		case _SHADOW_RMAP_REGION3:
			gmap_unshadow_sgt(sg, raddr);
			break;
		case _SHADOW_RMAP_SEGMENT:
			gmap_unshadow_pgt(sg, raddr);
			break;
		case _SHADOW_RMAP_PGTABLE:
			gmap_unshadow_page(sg, raddr);
			break;
		}
		kfree(rmap);
	}
	spin_unlock(&sg->guest_table_lock);
}
2065 2066 2067 2068 2069 2070

/**
 * ptep_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
2071
 * @bits: bits from the pgste that caused the notify call
2072 2073 2074 2075
 *
 * This function is assumed to be called with the page table lock held
 * for the pte to notify.
 */
2076 2077
void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
		 pte_t *pte, unsigned long bits)
2078 2079 2080
{
	unsigned long offset, gaddr;
	unsigned long *table;
2081
	struct gmap *gmap, *sg, *next;
2082 2083 2084

	offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
	offset = offset * (4096 / sizeof(pte_t));
2085 2086
	rcu_read_lock();
	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
2087 2088 2089 2090 2091 2092 2093 2094 2095
		if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
			spin_lock(&gmap->shadow_lock);
			list_for_each_entry_safe(sg, next,
						 &gmap->children, list)
				gmap_shadow_notify(sg, vmaddr, offset, pte);
			spin_unlock(&gmap->shadow_lock);
		}
		if (!(bits & PGSTE_IN_BIT))
			continue;
2096
		spin_lock(&gmap->guest_table_lock);
2097 2098
		table = radix_tree_lookup(&gmap->host_to_guest,
					  vmaddr >> PMD_SHIFT);
2099 2100 2101 2102 2103
		if (table)
			gaddr = __gmap_segment_gaddr(table) + offset;
		spin_unlock(&gmap->guest_table_lock);
		if (table)
			gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
2104
	}
2105
	rcu_read_unlock();
2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218
}
EXPORT_SYMBOL_GPL(ptep_notify);

static inline void thp_split_mm(struct mm_struct *mm)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	struct vm_area_struct *vma;
	unsigned long addr;

	for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
		for (addr = vma->vm_start;
		     addr < vma->vm_end;
		     addr += PAGE_SIZE)
			follow_page(vma, addr, FOLL_SPLIT);
		vma->vm_flags &= ~VM_HUGEPAGE;
		vma->vm_flags |= VM_NOHUGEPAGE;
	}
	mm->def_flags |= VM_NOHUGEPAGE;
#endif
}

/*
 * switch on pgstes for its userspace process (for kvm)
 */
int s390_enable_sie(void)
{
	struct mm_struct *mm = current->mm;

	/* Do we have pgstes? if yes, we are done */
	if (mm_has_pgste(mm))
		return 0;
	/* Fail if the page tables are 2K */
	if (!mm_alloc_pgste(mm))
		return -EINVAL;
	down_write(&mm->mmap_sem);
	mm->context.has_pgste = 1;
	/* split thp mappings and disable thp for future mappings */
	thp_split_mm(mm);
	up_write(&mm->mmap_sem);
	return 0;
}
EXPORT_SYMBOL_GPL(s390_enable_sie);

/*
 * Enable storage key handling from now on and initialize the storage
 * keys with the default key.
 */
static int __s390_enable_skey(pte_t *pte, unsigned long addr,
			      unsigned long next, struct mm_walk *walk)
{
	/*
	 * Remove all zero page mappings,
	 * after establishing a policy to forbid zero page mappings
	 * following faults for that page will get fresh anonymous pages
	 */
	if (is_zero_pfn(pte_pfn(*pte)))
		ptep_xchg_direct(walk->mm, addr, pte, __pte(_PAGE_INVALID));
	/* Clear storage key */
	ptep_zap_key(walk->mm, addr, pte);
	return 0;
}

int s390_enable_skey(void)
{
	struct mm_walk walk = { .pte_entry = __s390_enable_skey };
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	int rc = 0;

	down_write(&mm->mmap_sem);
	if (mm_use_skey(mm))
		goto out_up;

	mm->context.use_skey = 1;
	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
				MADV_UNMERGEABLE, &vma->vm_flags)) {
			mm->context.use_skey = 0;
			rc = -ENOMEM;
			goto out_up;
		}
	}
	mm->def_flags &= ~VM_MERGEABLE;

	walk.mm = mm;
	walk_page_range(0, TASK_SIZE, &walk);

out_up:
	up_write(&mm->mmap_sem);
	return rc;
}
EXPORT_SYMBOL_GPL(s390_enable_skey);

/*
 * Reset CMMA state, make all pages stable again.
 */
static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
			     unsigned long next, struct mm_walk *walk)
{
	ptep_zap_unused(walk->mm, addr, pte, 1);
	return 0;
}

void s390_reset_cmma(struct mm_struct *mm)
{
	struct mm_walk walk = { .pte_entry = __s390_reset_cmma };

	down_write(&mm->mmap_sem);
	walk.mm = mm;
	walk_page_range(0, TASK_SIZE, &walk);
	up_write(&mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(s390_reset_cmma);