// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2006-2009, Intel Corporation.
*
* Author: Anil S Keshavamurthy <[email protected]>
*/
#include <linux/iova.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/bitops.h>
#include <linux/cpu.h>
#include <linux/workqueue.h>
/* The anchor node sits above the top of the usable address space */
#define IOVA_ANCHOR ~0UL
#define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
static bool iova_rcache_insert(struct iova_domain *iovad,
unsigned long pfn,
unsigned long size);
static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long size,
unsigned long limit_pfn);
static void free_iova_rcaches(struct iova_domain *iovad);
static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad);
static void free_global_cached_iovas(struct iova_domain *iovad);
static struct iova *to_iova(struct rb_node *node)
{
return rb_entry(node, struct iova, node);
}
void
init_iova_domain(struct iova_domain *iovad, unsigned long granule,
unsigned long start_pfn)
{
/*
* IOVA granularity will normally be equal to the smallest
* supported IOMMU page size; both *must* be capable of
* representing individual CPU pages exactly.
*/
BUG_ON((granule > PAGE_SIZE) || !is_power_of_2(granule));
spin_lock_init(&iovad->iova_rbtree_lock);
iovad->rbroot = RB_ROOT;
iovad->cached_node = &iovad->anchor.node;
iovad->cached32_node = &iovad->anchor.node;
iovad->granule = granule;
iovad->start_pfn = start_pfn;
iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad));
iovad->max32_alloc_size = iovad->dma_32bit_pfn;
iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
rb_link_node(&iovad->anchor.node, NULL, &iovad->rbroot.rb_node);
rb_insert_color(&iovad->anchor.node, &iovad->rbroot);
}
EXPORT_SYMBOL_GPL(init_iova_domain);
static struct rb_node *
__get_cached_rbnode(struct iova_domain *iovad, unsigned long limit_pfn)
{
if (limit_pfn <= iovad->dma_32bit_pfn)
return iovad->cached32_node;
return iovad->cached_node;
}
static void
__cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
{
if (new->pfn_hi < iovad->dma_32bit_pfn)
iovad->cached32_node = &new->node;
else
iovad->cached_node = &new->node;
}
static void
__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
{
struct iova *cached_iova;
cached_iova = to_iova(iovad->cached32_node);
if (free == cached_iova ||
(free->pfn_hi < iovad->dma_32bit_pfn &&
free->pfn_lo >= cached_iova->pfn_lo))
iovad->cached32_node = rb_next(&free->node);
if (free->pfn_lo < iovad->dma_32bit_pfn)
iovad->max32_alloc_size = iovad->dma_32bit_pfn;
cached_iova = to_iova(iovad->cached_node);
if (free->pfn_lo >= cached_iova->pfn_lo)
iovad->cached_node = rb_next(&free->node);
}
static struct rb_node *iova_find_limit(struct iova_domain *iovad, unsigned long limit_pfn)
{
struct rb_node *node, *next;
/*
* Ideally what we'd like to judge here is whether limit_pfn is close
* enough to the highest-allocated IOVA that starting the allocation
* walk from the anchor node will be quicker than this initial work to
* find an exact starting point (especially if that ends up being the
* anchor node anyway). This is an incredibly crude approximation which
* only really helps the most likely case, but is at least trivially easy.
*/
if (limit_pfn > iovad->dma_32bit_pfn)
return &iovad->anchor.node;
node = iovad->rbroot.rb_node;
while (to_iova(node)->pfn_hi < limit_pfn)
node = node->rb_right;
search_left:
while (node->rb_left && to_iova(node->rb_left)->pfn_lo >= limit_pfn)
node = node->rb_left;
if (!node->rb_left)
return node;
next = node->rb_left;
while (next->rb_right) {
next = next->rb_right;
if (to_iova(next)->pfn_lo >= limit_pfn) {
node = next;
goto search_left;
}
}
return node;
}
/* Insert the iova into domain rbtree by holding writer lock */
static void
iova_insert_rbtree(struct rb_root *root, struct iova *iova,
struct rb_node *start)
{
struct rb_node **new, *parent = NULL;
new = (start) ? &start : &(root->rb_node);
/* Figure out where to put new node */
while (*new) {
struct iova *this = to_iova(*new);
parent = *new;
if (iova->pfn_lo < this->pfn_lo)
new = &((*new)->rb_left);
else if (iova->pfn_lo > this->pfn_lo)
new = &((*new)->rb_right);
else {
WARN_ON(1); /* this should not happen */
return;
}
}
/* Add new node and rebalance tree. */
rb_link_node(&iova->node, parent, new);
rb_insert_color(&iova->node, root);
}
static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
unsigned long size, unsigned long limit_pfn,
struct iova *new, bool size_aligned)
{
struct rb_node *curr, *prev;
struct iova *curr_iova;
unsigned long flags;
unsigned long new_pfn, retry_pfn;
unsigned long align_mask = ~0UL;
unsigned long high_pfn = limit_pfn, low_pfn = iovad->start_pfn;
if (size_aligned)
align_mask <<= fls_long(size - 1);
/* Walk the tree backwards */
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
if (limit_pfn <= iovad->dma_32bit_pfn &&
size >= iovad->max32_alloc_size)
goto iova32_full;
curr = __get_cached_rbnode(iovad, limit_pfn);
curr_iova = to_iova(curr);
retry_pfn = curr_iova->pfn_hi;
retry:
do {
high_pfn = min(high_pfn, curr_iova->pfn_lo);
new_pfn = (high_pfn - size) & align_mask;
prev = curr;
curr = rb_prev(curr);
curr_iova = to_iova(curr);
} while (curr && new_pfn <= curr_iova->pfn_hi && new_pfn >= low_pfn);
if (high_pfn < size || new_pfn < low_pfn) {
if (low_pfn == iovad->start_pfn && retry_pfn < limit_pfn) {
high_pfn = limit_pfn;
low_pfn = retry_pfn + 1;
curr = iova_find_limit(iovad, limit_pfn);
curr_iova = to_iova(curr);
goto retry;
}
iovad->max32_alloc_size = size;
goto iova32_full;
}
/* pfn_lo will point to size aligned address if size_aligned is set */
new->pfn_lo = new_pfn;
new->pfn_hi = new->pfn_lo + size - 1;
/* If we have 'prev', it's a valid place to start the insertion. */
iova_insert_rbtree(&iovad->rbroot, new, prev);
__cached_rbnode_insert_update(iovad, new);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return 0;
iova32_full:
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return -ENOMEM;
}
static struct kmem_cache *iova_cache;
static unsigned int iova_cache_users;
static DEFINE_MUTEX(iova_cache_mutex);
static struct iova *alloc_iova_mem(void)
{
return kmem_cache_zalloc(iova_cache, GFP_ATOMIC | __GFP_NOWARN);
}
static void free_iova_mem(struct iova *iova)
{
if (iova->pfn_lo != IOVA_ANCHOR)
kmem_cache_free(iova_cache, iova);
}
/**
* alloc_iova - allocates an iova
* @iovad: - iova domain in question
* @size: - size of page frames to allocate
* @limit_pfn: - max limit address
* @size_aligned: - set if size_aligned address range is required
* This function allocates an iova in the range iovad->start_pfn to limit_pfn,
* searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
* flag is set then the allocated address iova->pfn_lo will be naturally
* aligned on roundup_power_of_two(size).
*/
struct iova *
alloc_iova(struct iova_domain *iovad, unsigned long size,
unsigned long limit_pfn,
bool size_aligned)
{
struct iova *new_iova;
int ret;
new_iova = alloc_iova_mem();
if (!new_iova)
return NULL;
ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn + 1,
new_iova, size_aligned);
if (ret) {
free_iova_mem(new_iova);
return NULL;
}
return new_iova;
}
EXPORT_SYMBOL_GPL(alloc_iova);
static struct iova *
private_find_iova(struct iova_domain *iovad, unsigned long pfn)
{
struct rb_node *node = iovad->rbroot.rb_node;
assert_spin_locked(&iovad->iova_rbtree_lock);
while (node) {
struct iova *iova = to_iova(node);
if (pfn < iova->pfn_lo)
node = node->rb_left;
else if (pfn > iova->pfn_hi)
node = node->rb_right;
else
return iova; /* pfn falls within iova's range */
}
return NULL;
}
static void remove_iova(struct iova_domain *iovad, struct iova *iova)
{
assert_spin_locked(&iovad->iova_rbtree_lock);
__cached_rbnode_delete_update(iovad, iova);
rb_erase(&iova->node, &iovad->rbroot);
}
/**
* find_iova - finds an iova for a given pfn
* @iovad: - iova domain in question.
* @pfn: - page frame number
* This function finds and returns an iova belonging to the
* given domain which matches the given pfn.
*/
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
{
unsigned long flags;
struct iova *iova;
/* Take the lock so that no other thread is manipulating the rbtree */
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
iova = private_find_iova(iovad, pfn);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return iova;
}
EXPORT_SYMBOL_GPL(find_iova);
/**
* __free_iova - frees the given iova
* @iovad: iova domain in question.
* @iova: iova in question.
* Frees the given iova belonging to the giving domain
*/
void
__free_iova(struct iova_domain *iovad, struct iova *iova)
{
unsigned long flags;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
remove_iova(iovad, iova);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
free_iova_mem(iova);
}
EXPORT_SYMBOL_GPL(__free_iova);
/**
* free_iova - finds and frees the iova for a given pfn
* @iovad: - iova domain in question.
* @pfn: - pfn that is allocated previously
* This functions finds an iova for a given pfn and then
* frees the iova from that domain.
*/
void
free_iova(struct iova_domain *iovad, unsigned long pfn)
{
unsigned long flags;
struct iova *iova;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
iova = private_find_iova(iovad, pfn);
if (!iova) {
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return;
}
remove_iova(iovad, iova);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
free_iova_mem(iova);
}
EXPORT_SYMBOL_GPL(free_iova);
/**
* alloc_iova_fast - allocates an iova from rcache
* @iovad: - iova domain in question
* @size: - size of page frames to allocate
* @limit_pfn: - max limit address
* @flush_rcache: - set to flush rcache on regular allocation failure
* This function tries to satisfy an iova allocation from the rcache,
* and falls back to regular allocation on failure. If regular allocation
* fails too and the flush_rcache flag is set then the rcache will be flushed.
*/
unsigned long
alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
unsigned long limit_pfn, bool flush_rcache)
{
unsigned long iova_pfn;
struct iova *new_iova;
/*
* Freeing non-power-of-two-sized allocations back into the IOVA caches
* will come back to bite us badly, so we have to waste a bit of space
* rounding up anything cacheable to make sure that can't happen. The
* order of the unadjusted size will still match upon freeing.
*/
if (size < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
size = roundup_pow_of_two(size);
iova_pfn = iova_rcache_get(iovad, size, limit_pfn + 1);
if (iova_pfn)
return iova_pfn;
retry:
new_iova = alloc_iova(iovad, size, limit_pfn, true);
if (!new_iova) {
unsigned int cpu;
if (!flush_rcache)
return 0;
/* Try replenishing IOVAs by flushing rcache. */
flush_rcache = false;
for_each_online_cpu(cpu)
free_cpu_cached_iovas(cpu, iovad);
free_global_cached_iovas(iovad);
goto retry;
}
return new_iova->pfn_lo;
}
EXPORT_SYMBOL_GPL(alloc_iova_fast);
/**
* free_iova_fast - free iova pfn range into rcache
* @iovad: - iova domain in question.
* @pfn: - pfn that is allocated previously
* @size: - # of pages in range
* This functions frees an iova range by trying to put it into the rcache,
* falling back to regular iova deallocation via free_iova() if this fails.
*/
void
free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
{
if (iova_rcache_insert(iovad, pfn, size))
return;
free_iova(iovad, pfn);
}
EXPORT_SYMBOL_GPL(free_iova_fast);
static void iova_domain_free_rcaches(struct iova_domain *iovad)
{
cpuhp_state_remove_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
&iovad->cpuhp_dead);
free_iova_rcaches(iovad);
}
/**
* put_iova_domain - destroys the iova domain
* @iovad: - iova domain in question.
* All the iova's in that domain are destroyed.
*/
void put_iova_domain(struct iova_domain *iovad)
{
struct iova *iova, *tmp;
if (iovad->rcaches)
iova_domain_free_rcaches(iovad);
rbtree_postorder_for_each_entry_safe(iova, tmp, &iovad->rbroot, node)
free_iova_mem(iova);
}
EXPORT_SYMBOL_GPL(put_iova_domain);
static int
__is_range_overlap(struct rb_node *node,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova = to_iova(node);
if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
return 1;
return 0;
}
static inline struct iova *
alloc_and_init_iova(unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova;
iova = alloc_iova_mem();
if (iova) {
iova->pfn_lo = pfn_lo;
iova->pfn_hi = pfn_hi;
}
return iova;
}
static struct iova *
__insert_new_range(struct iova_domain *iovad,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova;
iova = alloc_and_init_iova(pfn_lo, pfn_hi);
if (iova)
iova_insert_rbtree(&iovad->rbroot, iova, NULL);
return iova;
}
static void
__adjust_overlap_range(struct iova *iova,
unsigned long *pfn_lo, unsigned long *pfn_hi)
{
if (*pfn_lo < iova->pfn_lo)
iova->pfn_lo = *pfn_lo;
if (*pfn_hi > iova->pfn_hi)
*pfn_lo = iova->pfn_hi + 1;
}
/**
* reserve_iova - reserves an iova in the given range
* @iovad: - iova domain pointer
* @pfn_lo: - lower page frame address
* @pfn_hi:- higher pfn adderss
* This function allocates reserves the address range from pfn_lo to pfn_hi so
* that this address is not dished out as part of alloc_iova.
*/
struct iova *
reserve_iova(struct iova_domain *iovad,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct rb_node *node;
unsigned long flags;
struct iova *iova;
unsigned int overlap = 0;
/* Don't allow nonsensical pfns */
if (WARN_ON((pfn_hi | pfn_lo) > (ULLONG_MAX >> iova_shift(iovad))))
return NULL;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
iova = to_iova(node);
__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
if ((pfn_lo >= iova->pfn_lo) &&
(pfn_hi <= iova->pfn_hi))
goto finish;
overlap = 1;
} else if (overlap)
break;
}
/* We are here either because this is the first reserver node
* or need to insert remaining non overlap addr range
*/
iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
finish:
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return iova;
}
EXPORT_SYMBOL_GPL(reserve_iova);
/*
* Magazine caches for IOVA ranges. For an introduction to magazines,
* see the USENIX 2001 paper "Magazines and Vmem: Extending the Slab
* Allocator to Many CPUs and Arbitrary Resources" by Bonwick and Adams.
* For simplicity, we use a static magazine size and don't implement the
* dynamic size tuning described in the paper.
*/
/*
* As kmalloc's buffer size is fixed to power of 2, 127 is chosen to
* assure size of 'iova_magazine' to be 1024 bytes, so that no memory
* will be wasted. Since only full magazines are inserted into the depot,
* we don't need to waste PFN capacity on a separate list head either.
*/
#define IOVA_MAG_SIZE 127
#define IOVA_DEPOT_DELAY msecs_to_jiffies(100)
struct iova_magazine {
union {
unsigned long size;
struct iova_magazine *next;
};
unsigned long pfns[IOVA_MAG_SIZE];
};
static_assert(!(sizeof(struct iova_magazine) & (sizeof(struct iova_magazine) - 1)));
struct iova_cpu_rcache {
spinlock_t lock;
struct iova_magazine *loaded;
struct iova_magazine *prev;
};
struct iova_rcache {
spinlock_t lock;
unsigned int depot_size;
struct iova_magazine *depot;
struct iova_cpu_rcache __percpu *cpu_rcaches;
struct iova_domain *iovad;
struct delayed_work work;
};
static struct kmem_cache *iova_magazine_cache;
unsigned long iova_rcache_range(void)
{
return PAGE_SIZE << (IOVA_RANGE_CACHE_MAX_SIZE - 1);
}
static struct iova_magazine *iova_magazine_alloc(gfp_t flags)
{
struct iova_magazine *mag;
mag = kmem_cache_alloc(iova_magazine_cache, flags);
if (mag)
mag->size = 0;
return mag;
}
static void iova_magazine_free(struct iova_magazine *mag)
{
kmem_cache_free(iova_magazine_cache, mag);
}
static void
iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
{
unsigned long flags;
int i;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
for (i = 0 ; i < mag->size; ++i) {
struct iova *iova = private_find_iova(iovad, mag->pfns[i]);
if (WARN_ON(!iova))
continue;
remove_iova(iovad, iova);
free_iova_mem(iova);
}
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
mag->size = 0;
}
static bool iova_magazine_full(struct iova_magazine *mag)
{
return mag->size == IOVA_MAG_SIZE;
}
static bool iova_magazine_empty(struct iova_magazine *mag)
{
return mag->size == 0;
}
static unsigned long iova_magazine_pop(struct iova_magazine *mag,
unsigned long limit_pfn)
{
int i;
unsigned long pfn;
/* Only fall back to the rbtree if we have no suitable pfns at all */
for (i = mag->size - 1; mag->pfns[i] > limit_pfn; i--)
if (i == 0)
return 0;
/* Swap it to pop it */
pfn = mag->pfns[i];
mag->pfns[i] = mag->pfns[--mag->size];
return pfn;
}
static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
{
mag->pfns[mag->size++] = pfn;
}
static struct iova_magazine *iova_depot_pop(struct iova_rcache *rcache)
{
struct iova_magazine *mag = rcache->depot;
rcache->depot = mag->next;
mag->size = IOVA_MAG_SIZE;
rcache->depot_size--;
return mag;
}
static void iova_depot_push(struct iova_rcache *rcache, struct iova_magazine *mag)
{
mag->next = rcache->depot;
rcache->depot = mag;
rcache->depot_size++;
}
static void iova_depot_work_func(struct work_struct *work)
{
struct iova_rcache *rcache = container_of(work, typeof(*rcache), work.work);
struct iova_magazine *mag = NULL;
unsigned long flags;
spin_lock_irqsave(&rcache->lock, flags);
if (rcache->depot_size > num_online_cpus())
mag = iova_depot_pop(rcache);
spin_unlock_irqrestore(&rcache->lock, flags);
if (mag) {
iova_magazine_free_pfns(mag, rcache->iovad);
iova_magazine_free(mag);
schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY);
}
}
int iova_domain_init_rcaches(struct iova_domain *iovad)
{
unsigned int cpu;
int i, ret;
iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
sizeof(struct iova_rcache),
GFP_KERNEL);
if (!iovad->rcaches)
return -ENOMEM;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
rcache = &iovad->rcaches[i];
spin_lock_init(&rcache->lock);
rcache->iovad = iovad;
INIT_DELAYED_WORK(&rcache->work, iova_depot_work_func);
rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache),
cache_line_size());
if (!rcache->cpu_rcaches) {
ret = -ENOMEM;
goto out_err;
}
for_each_possible_cpu(cpu) {
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
spin_lock_init(&cpu_rcache->lock);
cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL);
cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL);
if (!cpu_rcache->loaded || !cpu_rcache->prev) {
ret = -ENOMEM;
goto out_err;
}
}
}
ret = cpuhp_state_add_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
&iovad->cpuhp_dead);
if (ret)
goto out_err;
return 0;
out_err:
free_iova_rcaches(iovad);
return ret;
}
EXPORT_SYMBOL_GPL(iova_domain_init_rcaches);
/*
* Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
* return true on success. Can fail if rcache is full and we can't free
* space, and free_iova() (our only caller) will then return the IOVA
* range to the rbtree instead.
*/
static bool __iova_rcache_insert(struct iova_domain *iovad,
struct iova_rcache *rcache,
unsigned long iova_pfn)
{
struct iova_cpu_rcache *cpu_rcache;
bool can_insert = false;
unsigned long flags;
cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches);
spin_lock_irqsave(&cpu_rcache->lock, flags);
if (!iova_magazine_full(cpu_rcache->loaded)) {
can_insert = true;
} else if (!iova_magazine_full(cpu_rcache->prev)) {
swap(cpu_rcache->prev, cpu_rcache->loaded);
can_insert = true;
} else {
struct iova_magazine *new_mag = iova_magazine_alloc(GFP_ATOMIC);
if (new_mag) {
spin_lock(&rcache->lock);
iova_depot_push(rcache, cpu_rcache->loaded);
spin_unlock(&rcache->lock);
schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY);
cpu_rcache->loaded = new_mag;
can_insert = true;
}
}
if (can_insert)
iova_magazine_push(cpu_rcache->loaded, iova_pfn);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
return can_insert;
}
static bool iova_rcache_insert(struct iova_domain *iovad, unsigned long pfn,
unsigned long size)
{
unsigned int log_size = order_base_2(size);
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
return false;
return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
}
/*
* Caller wants to allocate a new IOVA range from 'rcache'. If we can
* satisfy the request, return a matching non-NULL range and remove
* it from the 'rcache'.
*/
static unsigned long __iova_rcache_get(struct iova_rcache *rcache,
unsigned long limit_pfn)
{
struct iova_cpu_rcache *cpu_rcache;
unsigned long iova_pfn = 0;
bool has_pfn = false;
unsigned long flags;
cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches);
spin_lock_irqsave(&cpu_rcache->lock, flags);
if (!iova_magazine_empty(cpu_rcache->loaded)) {
has_pfn = true;
} else if (!iova_magazine_empty(cpu_rcache->prev)) {
swap(cpu_rcache->prev, cpu_rcache->loaded);
has_pfn = true;
} else {
spin_lock(&rcache->lock);
if (rcache->depot) {
iova_magazine_free(cpu_rcache->loaded);
cpu_rcache->loaded = iova_depot_pop(rcache);
has_pfn = true;
}
spin_unlock(&rcache->lock);
}
if (has_pfn)
iova_pfn = iova_magazine_pop(cpu_rcache->loaded, limit_pfn);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
return iova_pfn;
}
/*
* Try to satisfy IOVA allocation range from rcache. Fail if requested
* size is too big or the DMA limit we are given isn't satisfied by the
* top element in the magazine.
*/
static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long size,
unsigned long limit_pfn)
{
unsigned int log_size = order_base_2(size);
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
return 0;
return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
}
/*
* free rcache data structures.
*/
static void free_iova_rcaches(struct iova_domain *iovad)
{
struct iova_rcache *rcache;
struct iova_cpu_rcache *cpu_rcache;
unsigned int cpu;
for (int i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
if (!rcache->cpu_rcaches)
break;
for_each_possible_cpu(cpu) {
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
iova_magazine_free(cpu_rcache->loaded);
iova_magazine_free(cpu_rcache->prev);
}
free_percpu(rcache->cpu_rcaches);
cancel_delayed_work_sync(&rcache->work);
while (rcache->depot)
iova_magazine_free(iova_depot_pop(rcache));
}
kfree(iovad->rcaches);
iovad->rcaches = NULL;
}
/*
* free all the IOVA ranges cached by a cpu (used when cpu is unplugged)
*/
static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
{
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
unsigned long flags;
int i;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
spin_lock_irqsave(&cpu_rcache->lock, flags);
iova_magazine_free_pfns(cpu_rcache->loaded, iovad);
iova_magazine_free_pfns(cpu_rcache->prev, iovad);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
}
}
/*
* free all the IOVA ranges of global cache
*/
static void free_global_cached_iovas(struct iova_domain *iovad)
{
struct iova_rcache *rcache;
unsigned long flags;
for (int i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
spin_lock_irqsave(&rcache->lock, flags);
while (rcache->depot) {
struct iova_magazine *mag = iova_depot_pop(rcache);
iova_magazine_free_pfns(mag, iovad);
iova_magazine_free(mag);
}
spin_unlock_irqrestore(&rcache->lock, flags);
}
}
static int iova_cpuhp_dead(unsigned int cpu, struct hlist_node *node)
{
struct iova_domain *iovad;
iovad = hlist_entry_safe(node, struct iova_domain, cpuhp_dead);
free_cpu_cached_iovas(cpu, iovad);
return 0;
}
int iova_cache_get(void)
{
int err = -ENOMEM;
mutex_lock(&iova_cache_mutex);
if (!iova_cache_users) {
iova_cache = kmem_cache_create("iommu_iova", sizeof(struct iova), 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!iova_cache)
goto out_err;
iova_magazine_cache = kmem_cache_create("iommu_iova_magazine",
sizeof(struct iova_magazine),
0, SLAB_HWCACHE_ALIGN, NULL);
if (!iova_magazine_cache)
goto out_err;
err = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead",
NULL, iova_cpuhp_dead);
if (err) {
pr_err("IOVA: Couldn't register cpuhp handler: %pe\n", ERR_PTR(err));
goto out_err;
}
}
iova_cache_users++;
mutex_unlock(&iova_cache_mutex);
return 0;
out_err:
kmem_cache_destroy(iova_cache);
kmem_cache_destroy(iova_magazine_cache);
mutex_unlock(&iova_cache_mutex);
return err;
}
EXPORT_SYMBOL_GPL(iova_cache_get);
void iova_cache_put(void)
{
mutex_lock(&iova_cache_mutex);
if (WARN_ON(!iova_cache_users)) {
mutex_unlock(&iova_cache_mutex);
return;
}
iova_cache_users--;
if (!iova_cache_users) {
cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
kmem_cache_destroy(iova_cache);
kmem_cache_destroy(iova_magazine_cache);
}
mutex_unlock(&iova_cache_mutex);
}
EXPORT_SYMBOL_GPL(iova_cache_put);
MODULE_AUTHOR("Anil S Keshavamurthy <[email protected]>");
MODULE_DESCRIPTION("IOMMU I/O Virtual Address management");
MODULE_LICENSE("GPL");
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