gmap.c 57.1 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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 * 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;

	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);
	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)
		__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);
}

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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;

	/* 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);
	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);

/*
 * 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));
	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);

/**
669
 * gmap_register_pte_notifier - register a pte invalidation callback
670 671
 * @nb: pointer to the gmap notifier block
 */
672
void gmap_register_pte_notifier(struct gmap_notifier *nb)
673 674
{
	spin_lock(&gmap_notifier_lock);
675
	list_add_rcu(&nb->list, &gmap_notifier_list);
676 677
	spin_unlock(&gmap_notifier_lock);
}
678
EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
679 680

/**
681
 * gmap_unregister_pte_notifier - remove a pte invalidation callback
682 683
 * @nb: pointer to the gmap notifier block
 */
684
void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
685 686
{
	spin_lock(&gmap_notifier_lock);
687
	list_del_rcu(&nb->list);
688
	spin_unlock(&gmap_notifier_lock);
689
	synchronize_rcu();
690
}
691
EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
692

693 694 695 696 697 698 699 700 701 702 703 704 705 706 707
/**
 * 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);
}

708
/**
709 710 711
 * gmap_table_walk - walk the gmap page tables
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
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 * @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.
723
 *
724
 * Note: Can also be called for shadow gmaps.
725 726
 */
static inline unsigned long *gmap_table_walk(struct gmap *gmap,
727
					     unsigned long gaddr, int level)
728 729 730
{
	unsigned long *table;

731 732 733 734 735 736
	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;
737 738 739 740
	table = gmap->table;
	switch (gmap->asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_REGION1:
		table += (gaddr >> 53) & 0x7ff;
741 742
		if (level == 4)
			break;
743 744 745 746 747 748
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION2:
		table += (gaddr >> 42) & 0x7ff;
749 750
		if (level == 3)
			break;
751 752 753 754 755 756
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_REGION3:
		table += (gaddr >> 31) & 0x7ff;
757 758
		if (level == 2)
			break;
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		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
		/* Fallthrough */
	case _ASCE_TYPE_SEGMENT:
		table += (gaddr >> 20) & 0x7ff;
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		if (level == 1)
			break;
		if (*table & _REGION_ENTRY_INVALID)
			return NULL;
		table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
		table += (gaddr >> 12) & 0xff;
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	}
	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
783 784
 *
 * Note: Can also be called for shadow gmaps.
785 786 787 788 789 790
 */
static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
			       spinlock_t **ptl)
{
	unsigned long *table;

791 792
	if (gmap_is_shadow(gmap))
		spin_lock(&gmap->guest_table_lock);
793
	/* Walk the gmap page table, lock and get pte pointer */
794 795 796 797
	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);
798
		return NULL;
799 800 801 802 803
	}
	if (gmap_is_shadow(gmap)) {
		*ptl = &gmap->guest_table_lock;
		return pte_offset_map((pmd_t *) table, gaddr);
	}
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	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
 *
 * 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,
			     unsigned long vmaddr)
{
	struct mm_struct *mm = gmap->mm;
	bool unlocked = false;

823
	BUG_ON(gmap_is_shadow(gmap));
824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841
	if (fixup_user_fault(current, mm, vmaddr, FAULT_FLAG_WRITE, &unlocked))
		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);
}

/**
 * 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);
}

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/*
 * gmap_protect_range - remove access rights to memory and set pgste bits
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
 * @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.
 *
 * Note: Can also be called for shadow gmaps.
 */
static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
			      unsigned long len, int prot, unsigned long bits)
{
	unsigned long vmaddr;
	spinlock_t *ptl;
	pte_t *ptep;
	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;
			rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
			if (rc)
				return rc;
			continue;
		}
		gaddr += PAGE_SIZE;
		len -= PAGE_SIZE;
	}
	return 0;
}

887 888 889
/**
 * gmap_mprotect_notify - change access rights for a range of ptes and
 *                        call the notifier if any pte changes again
890 891 892
 * @gmap: pointer to guest mapping meta data structure
 * @gaddr: virtual address in the guest address space
 * @len: size of area
893
 * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
894
 *
895 896 897 898 899
 * 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.
900
 */
901 902
int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
			 unsigned long len, int prot)
903
{
904
	int rc;
905

906
	if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
907
		return -EINVAL;
908 909
	if (!MACHINE_HAS_ESOP && prot == PROT_READ)
		return -EINVAL;
910
	down_read(&gmap->mm->mmap_sem);
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936
	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) {
937 938 939
		rc = -EAGAIN;
		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
		if (ptep) {
940 941 942 943 944 945 946 947 948
			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;
			}
949
			gmap_pte_op_end(ptl);
950
		}
951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
		if (!rc)
			break;
		vmaddr = __gmap_translate(gmap, gaddr);
		if (IS_ERR_VALUE(vmaddr)) {
			rc = vmaddr;
			break;
		}
		rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
		if (rc)
			break;
	}
	return rc;
}
EXPORT_SYMBOL_GPL(gmap_read_table);

/**
 * 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
 *
 * Called with the sg->guest_table_lock
 */
static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
				    struct gmap_rmap *rmap)
{
	void **slot;

	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);
		radix_tree_replace_slot(slot, rmap);
	} 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);
1024
		if (rc) {
1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
			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);
			rc = gmap_pte_op_fixup(parent, paddr, vmaddr);
1043
			if (rc)
1044
				return rc;
1045 1046
			continue;
		}
1047
		paddr += PAGE_SIZE;
1048
		len -= PAGE_SIZE;
1049
	}
1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 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 1162 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 1194 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 1220 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 1252 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 1278 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 1310 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 1336 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
	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 */
	if (!ste || *ste & _SEGMENT_ENTRY_INVALID)
		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) {
		if (sgt[i] & _SEGMENT_ENTRY_INVALID)
			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 */
	if (!r3e || *r3e & _REGION_ENTRY_INVALID)
		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) {
		if (r3t[i] & _REGION_ENTRY_INVALID)
			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 */
	if (!r2e || *r2e & _REGION_ENTRY_INVALID)
		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) {
		if (r2t[i] & _REGION_ENTRY_INVALID)
			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 */
	if (!r1e || *r1e & _REGION_ENTRY_INVALID)
		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) {
		if (r1t[i] & _REGION_ENTRY_INVALID)
			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);
1363
	gmap_flush_tlb(sg);
1364 1365 1366 1367 1368 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 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519
	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
 *
 * Returns the pointer to a gmap if a shadow table with the given asce is
 * already available, otherwise NULL
 */
static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce)
{
	struct gmap *sg;

	list_for_each_entry(sg, &parent->children, list) {
		if (sg->orig_asce != asce || sg->removed)
			continue;
		atomic_inc(&sg->ref_count);
		return sg;
	}
	return NULL;
}

/**
 * gmap_shadow - create/find a shadow guest address space
 * @parent: pointer to the parent gmap
 * @asce: ASCE for which the shadow table is created
 *
 * 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.
 *
 * Returns a guest address space structure, NULL if out of memory or if
 * anything goes wrong while protecting the top level pages.
 */
struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce)
{
	struct gmap *sg, *new;
	unsigned long limit;
	int rc;

	BUG_ON(gmap_is_shadow(parent));
	spin_lock(&parent->shadow_lock);
	sg = gmap_find_shadow(parent, asce);
	spin_unlock(&parent->shadow_lock);
	if (sg)
		return sg;
	/* Create a new shadow gmap */
	limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
	new = gmap_alloc(limit);
	if (!new)
		return NULL;
	new->mm = parent->mm;
	new->parent = gmap_get(parent);
	new->orig_asce = asce;
	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);
	if (rc) {
		atomic_set(&new->ref_count, 2);
		spin_lock(&parent->shadow_lock);
		/* Recheck if another CPU created the same shadow */
		sg = gmap_find_shadow(parent, asce);
		if (!sg) {
			list_add(&new->list, &parent->children);
			sg = new;
			new = NULL;
		}
		spin_unlock(&parent->shadow_lock);
	}
	if (new)
		gmap_free(new);
	return sg;
}
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
 *
 * 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.
 */
int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t)
{
	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;
	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;
	}
	crst_table_init(s_r2t, _REGION2_ENTRY_EMPTY);
	*table = (unsigned long) s_r2t |
		_REGION_ENTRY_LENGTH | _REGION_ENTRY_TYPE_R1;
	list_add(&page->lru, &sg->crst_list);
	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);
	if (rc) {
		spin_lock(&sg->guest_table_lock);
		gmap_unshadow_r2t(sg, raddr);
		spin_unlock(&sg->guest_table_lock);
	}
	return rc;
out_free:
	spin_unlock(&sg->guest_table_lock);
	__free_pages(page, 2);
1520 1521
	return rc;
}
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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
 *
 * 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.
 */
int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t)
{
	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;
	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;
	}
	crst_table_init(s_r3t, _REGION3_ENTRY_EMPTY);
	*table = (unsigned long) s_r3t |
		_REGION_ENTRY_LENGTH | _REGION_ENTRY_TYPE_R2;
	list_add(&page->lru, &sg->crst_list);
	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);
	if (rc) {
		spin_lock(&sg->guest_table_lock);
		gmap_unshadow_r3t(sg, raddr);
		spin_unlock(&sg->guest_table_lock);
	}
	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
 *
 * 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.
 */
int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt)
{
	unsigned long raddr, origin, offset, len;
	unsigned long *s_sgt, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow segment table */
	page = alloc_pages(GFP_KERNEL, 2);
	if (!page)
		return -ENOMEM;
	page->index = sgt & _REGION_ENTRY_ORIGIN;
	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;
	}
	crst_table_init(s_sgt, _SEGMENT_ENTRY_EMPTY);
	*table = (unsigned long) s_sgt |
		_REGION_ENTRY_LENGTH | _REGION_ENTRY_TYPE_R3;
	list_add(&page->lru, &sg->crst_list);
	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);
	if (rc) {
		spin_lock(&sg->guest_table_lock);
		gmap_unshadow_sgt(sg, raddr);
		spin_unlock(&sg->guest_table_lock);
	}
	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
 *
 * 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,
			   unsigned long *pgt, int *dat_protection)
{
	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);
		*pgt = page->index;
		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
		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
 *
 * 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
 */
int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt)
{
	unsigned long raddr, origin;
	unsigned long *s_pgt, *table;
	struct page *page;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	/* Allocate a shadow page table */
	page = page_table_alloc_pgste(sg->mm);
	if (!page)
		return -ENOMEM;
	page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
	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;
	}
	*table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
		 (pgt & _SEGMENT_ENTRY_PROTECT);
	list_add(&page->lru, &sg->pt_list);
	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);
	if (rc) {
		spin_lock(&sg->guest_table_lock);
		gmap_unshadow_pgt(sg, raddr);
		spin_unlock(&sg->guest_table_lock);
	}
	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
1746
 * @pte: pte in parent gmap address space to get shadowed
1747 1748 1749 1750 1751 1752 1753
 *
 * 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.
 */
1754
int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
1755 1756 1757
{
	struct gmap *parent;
	struct gmap_rmap *rmap;
1758
	unsigned long vmaddr, paddr;
1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771
	spinlock_t *ptl;
	pte_t *sptep, *tptep;
	int rc;

	BUG_ON(!gmap_is_shadow(sg));
	parent = sg->parent;

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

	while (1) {
1772
		paddr = pte_val(pte) & PAGE_MASK;
1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792
		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;
			}
1793
			rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877
			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;
		rc = gmap_pte_op_fixup(parent, paddr, vmaddr);
		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;
	if (gaddr >= start && gaddr < end) {
		/* 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);
}
1878 1879 1880 1881 1882 1883

/**
 * 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
1884
 * @bits: bits from the pgste that caused the notify call
1885 1886 1887 1888
 *
 * This function is assumed to be called with the page table lock held
 * for the pte to notify.
 */
1889 1890
void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
		 pte_t *pte, unsigned long bits)
1891 1892 1893
{
	unsigned long offset, gaddr;
	unsigned long *table;
1894
	struct gmap *gmap, *sg, *next;
1895 1896 1897

	offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
	offset = offset * (4096 / sizeof(pte_t));
1898 1899
	rcu_read_lock();
	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
1900 1901 1902 1903 1904 1905 1906 1907 1908
		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;
1909
		spin_lock(&gmap->guest_table_lock);
1910 1911
		table = radix_tree_lookup(&gmap->host_to_guest,
					  vmaddr >> PMD_SHIFT);
1912 1913 1914 1915 1916
		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);
1917
	}
1918
	rcu_read_unlock();
1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 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 2030 2031
}
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);