diff options
Diffstat (limited to 'drivers/iommu/iova.c')
| -rw-r--r-- | drivers/iommu/iova.c | 1052 |
1 files changed, 1052 insertions, 0 deletions
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c new file mode 100644 index 000000000..fdd68d8e8 --- /dev/null +++ b/drivers/iommu/iova.c @@ -0,0 +1,1052 @@ +/* + * Copyright © 2006-2009, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple + * Place - Suite 330, Boston, MA 02111-1307 USA. + * + * 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_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); + +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->flush_cb = 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); + init_iova_rcaches(iovad); +} +EXPORT_SYMBOL_GPL(init_iova_domain); + +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->flush_cb = NULL; + iovad->entry_dtor = NULL; +} + +int init_iova_flush_queue(struct iova_domain *iovad, + iova_flush_cb flush_cb, iova_entry_dtor entry_dtor) +{ + 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; + + iovad->flush_cb = flush_cb; + iovad->entry_dtor = entry_dtor; + + 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); + } + + smp_wmb(); + + iovad->fq = queue; + + timer_setup(&iovad->fq_timer, fq_flush_timeout, 0); + atomic_set(&iovad->fq_timer_on, 0); + + return 0; +} +EXPORT_SYMBOL_GPL(init_iova_flush_queue); + +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 = rb_entry(iovad->cached32_node, struct iova, 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); + + cached_iova = rb_entry(iovad->cached_node, struct iova, node); + if (free->pfn_lo >= cached_iova->pfn_lo) + iovad->cached_node = rb_next(&free->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 = rb_entry(*new, struct iova, node); + + 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; + unsigned long align_mask = ~0UL; + + if (size_aligned) + align_mask <<= fls_long(size - 1); + + /* Walk the tree backwards */ + spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); + curr = __get_cached_rbnode(iovad, limit_pfn); + curr_iova = rb_entry(curr, struct iova, node); + do { + limit_pfn = min(limit_pfn, curr_iova->pfn_lo); + new_pfn = (limit_pfn - size) & align_mask; + prev = curr; + curr = rb_prev(curr); + curr_iova = rb_entry(curr, struct iova, node); + } while (curr && new_pfn <= curr_iova->pfn_hi); + + if (limit_pfn < size || new_pfn < iovad->start_pfn) { + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); + return -ENOMEM; + } + + /* 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; +} + +static struct kmem_cache *iova_cache; +static unsigned int iova_cache_users; +static DEFINE_MUTEX(iova_cache_mutex); + +struct iova *alloc_iova_mem(void) +{ + return kmem_cache_zalloc(iova_cache, GFP_ATOMIC); +} +EXPORT_SYMBOL(alloc_iova_mem); + +void free_iova_mem(struct iova *iova) +{ + if (iova->pfn_lo != IOVA_ANCHOR) + kmem_cache_free(iova_cache, iova); +} +EXPORT_SYMBOL(free_iova_mem); + +int iova_cache_get(void) +{ + 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) { + mutex_unlock(&iova_cache_mutex); + printk(KERN_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) + 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 = rb_entry(node, struct 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 private_free_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); + free_iova_mem(iova); +} + +/** + * 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 doamin 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); + private_free_iova(iovad, iova); + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); +} +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) +{ + struct iova *iova = find_iova(iovad, pfn); + + if (iova) + __free_iova(iovad, 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; + + 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); + 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); + +#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; + + if (iovad->entry_dtor) + iovad->entry_dtor(fq->entries[idx].data); + + 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->flush_cb(iovad); + 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. + */ + if (!iovad->entry_dtor) + return; + + for_each_possible_cpu(cpu) { + struct iova_fq *fq = per_cpu_ptr(iovad->fq, cpu); + int idx; + + fq_ring_for_each(idx, fq) + iovad->entry_dtor(fq->entries[idx].data); + } +} + +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, + unsigned long data) +{ + struct iova_fq *fq = raw_cpu_ptr(iovad->fq); + unsigned long flags; + unsigned idx; + + 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].data = data; + 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_cmpxchg(&iovad->fq_timer_on, 0, 1)) + mod_timer(&iovad->fq_timer, + jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT)); +} +EXPORT_SYMBOL_GPL(queue_iova); + +/** + * put_iova_domain - destroys the iova doamin + * @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; + + 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 = rb_entry(node, struct 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 = rb_entry(node, struct 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); + +/** + * copy_reserved_iova - copies the reserved between domains + * @from: - source doamin from where to copy + * @to: - destination domin where to copy + * This function copies reserved iova's from one doamin to + * other. + */ +void +copy_reserved_iova(struct iova_domain *from, struct iova_domain *to) +{ + unsigned long flags; + struct rb_node *node; + + spin_lock_irqsave(&from->iova_rbtree_lock, flags); + for (node = rb_first(&from->rbroot); node; node = rb_next(node)) { + struct iova *iova = rb_entry(node, struct iova, node); + struct iova *new_iova; + + if (iova->pfn_lo == IOVA_ANCHOR) + continue; + + new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi); + if (!new_iova) + printk(KERN_ERR "Reserve iova range %lx@%lx failed\n", + iova->pfn_lo, iova->pfn_lo); + } + spin_unlock_irqrestore(&from->iova_rbtree_lock, flags); +} +EXPORT_SYMBOL_GPL(copy_reserved_iova); + +struct iova * +split_and_remove_iova(struct iova_domain *iovad, struct iova *iova, + unsigned long pfn_lo, unsigned long pfn_hi) +{ + unsigned long flags; + struct iova *prev = NULL, *next = NULL; + + spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); + if (iova->pfn_lo < pfn_lo) { + prev = alloc_and_init_iova(iova->pfn_lo, pfn_lo - 1); + if (prev == NULL) + goto error; + } + if (iova->pfn_hi > pfn_hi) { + next = alloc_and_init_iova(pfn_hi + 1, iova->pfn_hi); + if (next == NULL) + goto error; + } + + __cached_rbnode_delete_update(iovad, iova); + rb_erase(&iova->node, &iovad->rbroot); + + if (prev) { + iova_insert_rbtree(&iovad->rbroot, prev, NULL); + iova->pfn_lo = pfn_lo; + } + if (next) { + iova_insert_rbtree(&iovad->rbroot, next, NULL); + iova->pfn_hi = pfn_hi; + } + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); + + return iova; + +error: + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); + if (prev) + free_iova_mem(prev); + return NULL; +} + +/* + * 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; + + private_free_iova(iovad, 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) + */ +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); + } +} + +MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>"); +MODULE_LICENSE("GPL"); |