linux/drivers/iommu/iova.c
Robin Murphy 649ad9835a iommu/iova: Squash flush_cb abstraction
Once again, with iommu-dma now being the only flush queue user, we no
longer need the extra level of indirection through flush_cb. Squash that
and let the flush queue code call the domain method directly. This does
mean temporarily having to carry an additional copy of the IOMMU domain
pointer around instead, but only until a later patch untangles it again.

Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/e3f9b4acdd6640012ef4fbc819ac868d727b64a9.1639753638.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
2021-12-20 09:03:05 +01:00

1105 lines
28 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2006-2009, Intel Corporation.
*
* Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
*/
#include <linux/iova.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/bitops.h>
#include <linux/cpu.h>
/* The anchor node sits above the top of the usable address space */
#define IOVA_ANCHOR ~0UL
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 init_iova_rcaches(struct iova_domain *iovad);
static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad);
static void free_iova_rcaches(struct iova_domain *iovad);
static void fq_destroy_all_entries(struct iova_domain *iovad);
static void fq_flush_timeout(struct timer_list *t);
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;
}
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->fq_domain = NULL;
iovad->fq = NULL;
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);
cpuhp_state_add_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD, &iovad->cpuhp_dead);
init_iova_rcaches(iovad);
}
EXPORT_SYMBOL_GPL(init_iova_domain);
static bool has_iova_flush_queue(struct iova_domain *iovad)
{
return !!iovad->fq;
}
static void free_iova_flush_queue(struct iova_domain *iovad)
{
if (!has_iova_flush_queue(iovad))
return;
del_timer_sync(&iovad->fq_timer);
fq_destroy_all_entries(iovad);
free_percpu(iovad->fq);
iovad->fq = NULL;
iovad->fq_domain = NULL;
}
int init_iova_flush_queue(struct iova_domain *iovad, struct iommu_domain *fq_domain)
{
struct iova_fq __percpu *queue;
int cpu;
atomic64_set(&iovad->fq_flush_start_cnt, 0);
atomic64_set(&iovad->fq_flush_finish_cnt, 0);
queue = alloc_percpu(struct iova_fq);
if (!queue)
return -ENOMEM;
for_each_possible_cpu(cpu) {
struct iova_fq *fq;
fq = per_cpu_ptr(queue, cpu);
fq->head = 0;
fq->tail = 0;
spin_lock_init(&fq->lock);
}
iovad->fq_domain = fq_domain;
iovad->fq = queue;
timer_setup(&iovad->fq_timer, fq_flush_timeout, 0);
atomic_set(&iovad->fq_timer_on, 0);
return 0;
}
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);
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 + 1;
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;
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);
}
int iova_cache_get(void)
{
mutex_lock(&iova_cache_mutex);
if (!iova_cache_users) {
int ret;
ret = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead", NULL,
iova_cpuhp_dead);
if (ret) {
mutex_unlock(&iova_cache_mutex);
pr_err("Couldn't register cpuhp handler\n");
return ret;
}
iova_cache = kmem_cache_create(
"iommu_iova", sizeof(struct iova), 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!iova_cache) {
cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
mutex_unlock(&iova_cache_mutex);
pr_err("Couldn't create iova cache\n");
return -ENOMEM;
}
}
iova_cache_users++;
mutex_unlock(&iova_cache_mutex);
return 0;
}
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);
}
mutex_unlock(&iova_cache_mutex);
}
EXPORT_SYMBOL_GPL(iova_cache_put);
/**
* 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 fq_entry_dtor(struct page *freelist)
{
while (freelist) {
unsigned long p = (unsigned long)page_address(freelist);
freelist = freelist->freelist;
free_page(p);
}
}
#define fq_ring_for_each(i, fq) \
for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) % IOVA_FQ_SIZE)
static inline bool fq_full(struct iova_fq *fq)
{
assert_spin_locked(&fq->lock);
return (((fq->tail + 1) % IOVA_FQ_SIZE) == fq->head);
}
static inline unsigned fq_ring_add(struct iova_fq *fq)
{
unsigned idx = fq->tail;
assert_spin_locked(&fq->lock);
fq->tail = (idx + 1) % IOVA_FQ_SIZE;
return idx;
}
static void fq_ring_free(struct iova_domain *iovad, struct iova_fq *fq)
{
u64 counter = atomic64_read(&iovad->fq_flush_finish_cnt);
unsigned idx;
assert_spin_locked(&fq->lock);
fq_ring_for_each(idx, fq) {
if (fq->entries[idx].counter >= counter)
break;
fq_entry_dtor(fq->entries[idx].freelist);
free_iova_fast(iovad,
fq->entries[idx].iova_pfn,
fq->entries[idx].pages);
fq->head = (fq->head + 1) % IOVA_FQ_SIZE;
}
}
static void iova_domain_flush(struct iova_domain *iovad)
{
atomic64_inc(&iovad->fq_flush_start_cnt);
iovad->fq_domain->ops->flush_iotlb_all(iovad->fq_domain);
atomic64_inc(&iovad->fq_flush_finish_cnt);
}
static void fq_destroy_all_entries(struct iova_domain *iovad)
{
int cpu;
/*
* This code runs when the iova_domain is being detroyed, so don't
* bother to free iovas, just call the entry_dtor on all remaining
* entries.
*/
for_each_possible_cpu(cpu) {
struct iova_fq *fq = per_cpu_ptr(iovad->fq, cpu);
int idx;
fq_ring_for_each(idx, fq)
fq_entry_dtor(fq->entries[idx].freelist);
}
}
static void fq_flush_timeout(struct timer_list *t)
{
struct iova_domain *iovad = from_timer(iovad, t, fq_timer);
int cpu;
atomic_set(&iovad->fq_timer_on, 0);
iova_domain_flush(iovad);
for_each_possible_cpu(cpu) {
unsigned long flags;
struct iova_fq *fq;
fq = per_cpu_ptr(iovad->fq, cpu);
spin_lock_irqsave(&fq->lock, flags);
fq_ring_free(iovad, fq);
spin_unlock_irqrestore(&fq->lock, flags);
}
}
void queue_iova(struct iova_domain *iovad,
unsigned long pfn, unsigned long pages,
struct page *freelist)
{
struct iova_fq *fq;
unsigned long flags;
unsigned idx;
/*
* Order against the IOMMU driver's pagetable update from unmapping
* @pte, to guarantee that iova_domain_flush() observes that if called
* from a different CPU before we release the lock below. Full barrier
* so it also pairs with iommu_dma_init_fq() to avoid seeing partially
* written fq state here.
*/
smp_mb();
fq = raw_cpu_ptr(iovad->fq);
spin_lock_irqsave(&fq->lock, flags);
/*
* First remove all entries from the flush queue that have already been
* flushed out on another CPU. This makes the fq_full() check below less
* likely to be true.
*/
fq_ring_free(iovad, fq);
if (fq_full(fq)) {
iova_domain_flush(iovad);
fq_ring_free(iovad, fq);
}
idx = fq_ring_add(fq);
fq->entries[idx].iova_pfn = pfn;
fq->entries[idx].pages = pages;
fq->entries[idx].freelist = freelist;
fq->entries[idx].counter = atomic64_read(&iovad->fq_flush_start_cnt);
spin_unlock_irqrestore(&fq->lock, flags);
/* Avoid false sharing as much as possible. */
if (!atomic_read(&iovad->fq_timer_on) &&
!atomic_xchg(&iovad->fq_timer_on, 1))
mod_timer(&iovad->fq_timer,
jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
}
/**
* 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;
cpuhp_state_remove_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
&iovad->cpuhp_dead);
free_iova_flush_queue(iovad);
free_iova_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.
*/
#define IOVA_MAG_SIZE 128
struct iova_magazine {
unsigned long size;
unsigned long pfns[IOVA_MAG_SIZE];
};
struct iova_cpu_rcache {
spinlock_t lock;
struct iova_magazine *loaded;
struct iova_magazine *prev;
};
static struct iova_magazine *iova_magazine_alloc(gfp_t flags)
{
return kzalloc(sizeof(struct iova_magazine), flags);
}
static void iova_magazine_free(struct iova_magazine *mag)
{
kfree(mag);
}
static void
iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
{
unsigned long flags;
int i;
if (!mag)
return;
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 && mag->size == IOVA_MAG_SIZE);
}
static bool iova_magazine_empty(struct iova_magazine *mag)
{
return (!mag || mag->size == 0);
}
static unsigned long iova_magazine_pop(struct iova_magazine *mag,
unsigned long limit_pfn)
{
int i;
unsigned long pfn;
BUG_ON(iova_magazine_empty(mag));
/* 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)
{
BUG_ON(iova_magazine_full(mag));
mag->pfns[mag->size++] = pfn;
}
static void init_iova_rcaches(struct iova_domain *iovad)
{
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
unsigned int cpu;
int i;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
spin_lock_init(&rcache->lock);
rcache->depot_size = 0;
rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache), cache_line_size());
if (WARN_ON(!rcache->cpu_rcaches))
continue;
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);
}
}
}
/*
* 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_magazine *mag_to_free = NULL;
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);
if (rcache->depot_size < MAX_GLOBAL_MAGS) {
rcache->depot[rcache->depot_size++] =
cpu_rcache->loaded;
} else {
mag_to_free = cpu_rcache->loaded;
}
spin_unlock(&rcache->lock);
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);
if (mag_to_free) {
iova_magazine_free_pfns(mag_to_free, iovad);
iova_magazine_free(mag_to_free);
}
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_size > 0) {
iova_magazine_free(cpu_rcache->loaded);
cpu_rcache->loaded = rcache->depot[--rcache->depot_size];
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;
int i, j;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
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);
for (j = 0; j < rcache->depot_size; ++j)
iova_magazine_free(rcache->depot[j]);
}
}
/*
* 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;
int i, j;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
spin_lock_irqsave(&rcache->lock, flags);
for (j = 0; j < rcache->depot_size; ++j) {
iova_magazine_free_pfns(rcache->depot[j], iovad);
iova_magazine_free(rcache->depot[j]);
}
rcache->depot_size = 0;
spin_unlock_irqrestore(&rcache->lock, flags);
}
}
MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>");
MODULE_LICENSE("GPL");