diff options
Diffstat (limited to 'drivers/iommu/iommufd/io_pagetable.c')
| -rw-r--r-- | drivers/iommu/iommufd/io_pagetable.c | 1244 |
1 files changed, 1244 insertions, 0 deletions
diff --git a/drivers/iommu/iommufd/io_pagetable.c b/drivers/iommu/iommufd/io_pagetable.c new file mode 100644 index 0000000000..117a39ae2e --- /dev/null +++ b/drivers/iommu/iommufd/io_pagetable.c @@ -0,0 +1,1244 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES. + * + * The io_pagetable is the top of datastructure that maps IOVA's to PFNs. The + * PFNs can be placed into an iommu_domain, or returned to the caller as a page + * list for access by an in-kernel user. + * + * The datastructure uses the iopt_pages to optimize the storage of the PFNs + * between the domains and xarray. + */ +#include <linux/iommufd.h> +#include <linux/lockdep.h> +#include <linux/iommu.h> +#include <linux/sched/mm.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/errno.h> + +#include "io_pagetable.h" +#include "double_span.h" + +struct iopt_pages_list { + struct iopt_pages *pages; + struct iopt_area *area; + struct list_head next; + unsigned long start_byte; + unsigned long length; +}; + +struct iopt_area *iopt_area_contig_init(struct iopt_area_contig_iter *iter, + struct io_pagetable *iopt, + unsigned long iova, + unsigned long last_iova) +{ + lockdep_assert_held(&iopt->iova_rwsem); + + iter->cur_iova = iova; + iter->last_iova = last_iova; + iter->area = iopt_area_iter_first(iopt, iova, iova); + if (!iter->area) + return NULL; + if (!iter->area->pages) { + iter->area = NULL; + return NULL; + } + return iter->area; +} + +struct iopt_area *iopt_area_contig_next(struct iopt_area_contig_iter *iter) +{ + unsigned long last_iova; + + if (!iter->area) + return NULL; + last_iova = iopt_area_last_iova(iter->area); + if (iter->last_iova <= last_iova) + return NULL; + + iter->cur_iova = last_iova + 1; + iter->area = iopt_area_iter_next(iter->area, iter->cur_iova, + iter->last_iova); + if (!iter->area) + return NULL; + if (iter->cur_iova != iopt_area_iova(iter->area) || + !iter->area->pages) { + iter->area = NULL; + return NULL; + } + return iter->area; +} + +static bool __alloc_iova_check_hole(struct interval_tree_double_span_iter *span, + unsigned long length, + unsigned long iova_alignment, + unsigned long page_offset) +{ + if (span->is_used || span->last_hole - span->start_hole < length - 1) + return false; + + span->start_hole = ALIGN(span->start_hole, iova_alignment) | + page_offset; + if (span->start_hole > span->last_hole || + span->last_hole - span->start_hole < length - 1) + return false; + return true; +} + +static bool __alloc_iova_check_used(struct interval_tree_span_iter *span, + unsigned long length, + unsigned long iova_alignment, + unsigned long page_offset) +{ + if (span->is_hole || span->last_used - span->start_used < length - 1) + return false; + + span->start_used = ALIGN(span->start_used, iova_alignment) | + page_offset; + if (span->start_used > span->last_used || + span->last_used - span->start_used < length - 1) + return false; + return true; +} + +/* + * Automatically find a block of IOVA that is not being used and not reserved. + * Does not return a 0 IOVA even if it is valid. + */ +static int iopt_alloc_iova(struct io_pagetable *iopt, unsigned long *iova, + unsigned long uptr, unsigned long length) +{ + unsigned long page_offset = uptr % PAGE_SIZE; + struct interval_tree_double_span_iter used_span; + struct interval_tree_span_iter allowed_span; + unsigned long iova_alignment; + + lockdep_assert_held(&iopt->iova_rwsem); + + /* Protect roundup_pow-of_two() from overflow */ + if (length == 0 || length >= ULONG_MAX / 2) + return -EOVERFLOW; + + /* + * Keep alignment present in the uptr when building the IOVA, this + * increases the chance we can map a THP. + */ + if (!uptr) + iova_alignment = roundup_pow_of_two(length); + else + iova_alignment = min_t(unsigned long, + roundup_pow_of_two(length), + 1UL << __ffs64(uptr)); + + if (iova_alignment < iopt->iova_alignment) + return -EINVAL; + + interval_tree_for_each_span(&allowed_span, &iopt->allowed_itree, + PAGE_SIZE, ULONG_MAX - PAGE_SIZE) { + if (RB_EMPTY_ROOT(&iopt->allowed_itree.rb_root)) { + allowed_span.start_used = PAGE_SIZE; + allowed_span.last_used = ULONG_MAX - PAGE_SIZE; + allowed_span.is_hole = false; + } + + if (!__alloc_iova_check_used(&allowed_span, length, + iova_alignment, page_offset)) + continue; + + interval_tree_for_each_double_span( + &used_span, &iopt->reserved_itree, &iopt->area_itree, + allowed_span.start_used, allowed_span.last_used) { + if (!__alloc_iova_check_hole(&used_span, length, + iova_alignment, + page_offset)) + continue; + + *iova = used_span.start_hole; + return 0; + } + } + return -ENOSPC; +} + +static int iopt_check_iova(struct io_pagetable *iopt, unsigned long iova, + unsigned long length) +{ + unsigned long last; + + lockdep_assert_held(&iopt->iova_rwsem); + + if ((iova & (iopt->iova_alignment - 1))) + return -EINVAL; + + if (check_add_overflow(iova, length - 1, &last)) + return -EOVERFLOW; + + /* No reserved IOVA intersects the range */ + if (iopt_reserved_iter_first(iopt, iova, last)) + return -EINVAL; + + /* Check that there is not already a mapping in the range */ + if (iopt_area_iter_first(iopt, iova, last)) + return -EEXIST; + return 0; +} + +/* + * The area takes a slice of the pages from start_bytes to start_byte + length + */ +static int iopt_insert_area(struct io_pagetable *iopt, struct iopt_area *area, + struct iopt_pages *pages, unsigned long iova, + unsigned long start_byte, unsigned long length, + int iommu_prot) +{ + lockdep_assert_held_write(&iopt->iova_rwsem); + + if ((iommu_prot & IOMMU_WRITE) && !pages->writable) + return -EPERM; + + area->iommu_prot = iommu_prot; + area->page_offset = start_byte % PAGE_SIZE; + if (area->page_offset & (iopt->iova_alignment - 1)) + return -EINVAL; + + area->node.start = iova; + if (check_add_overflow(iova, length - 1, &area->node.last)) + return -EOVERFLOW; + + area->pages_node.start = start_byte / PAGE_SIZE; + if (check_add_overflow(start_byte, length - 1, &area->pages_node.last)) + return -EOVERFLOW; + area->pages_node.last = area->pages_node.last / PAGE_SIZE; + if (WARN_ON(area->pages_node.last >= pages->npages)) + return -EOVERFLOW; + + /* + * The area is inserted with a NULL pages indicating it is not fully + * initialized yet. + */ + area->iopt = iopt; + interval_tree_insert(&area->node, &iopt->area_itree); + return 0; +} + +static struct iopt_area *iopt_area_alloc(void) +{ + struct iopt_area *area; + + area = kzalloc(sizeof(*area), GFP_KERNEL_ACCOUNT); + if (!area) + return NULL; + RB_CLEAR_NODE(&area->node.rb); + RB_CLEAR_NODE(&area->pages_node.rb); + return area; +} + +static int iopt_alloc_area_pages(struct io_pagetable *iopt, + struct list_head *pages_list, + unsigned long length, unsigned long *dst_iova, + int iommu_prot, unsigned int flags) +{ + struct iopt_pages_list *elm; + unsigned long iova; + int rc = 0; + + list_for_each_entry(elm, pages_list, next) { + elm->area = iopt_area_alloc(); + if (!elm->area) + return -ENOMEM; + } + + down_write(&iopt->iova_rwsem); + if ((length & (iopt->iova_alignment - 1)) || !length) { + rc = -EINVAL; + goto out_unlock; + } + + if (flags & IOPT_ALLOC_IOVA) { + /* Use the first entry to guess the ideal IOVA alignment */ + elm = list_first_entry(pages_list, struct iopt_pages_list, + next); + rc = iopt_alloc_iova( + iopt, dst_iova, + (uintptr_t)elm->pages->uptr + elm->start_byte, length); + if (rc) + goto out_unlock; + if (IS_ENABLED(CONFIG_IOMMUFD_TEST) && + WARN_ON(iopt_check_iova(iopt, *dst_iova, length))) { + rc = -EINVAL; + goto out_unlock; + } + } else { + rc = iopt_check_iova(iopt, *dst_iova, length); + if (rc) + goto out_unlock; + } + + /* + * Areas are created with a NULL pages so that the IOVA space is + * reserved and we can unlock the iova_rwsem. + */ + iova = *dst_iova; + list_for_each_entry(elm, pages_list, next) { + rc = iopt_insert_area(iopt, elm->area, elm->pages, iova, + elm->start_byte, elm->length, iommu_prot); + if (rc) + goto out_unlock; + iova += elm->length; + } + +out_unlock: + up_write(&iopt->iova_rwsem); + return rc; +} + +static void iopt_abort_area(struct iopt_area *area) +{ + if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) + WARN_ON(area->pages); + if (area->iopt) { + down_write(&area->iopt->iova_rwsem); + interval_tree_remove(&area->node, &area->iopt->area_itree); + up_write(&area->iopt->iova_rwsem); + } + kfree(area); +} + +void iopt_free_pages_list(struct list_head *pages_list) +{ + struct iopt_pages_list *elm; + + while ((elm = list_first_entry_or_null(pages_list, + struct iopt_pages_list, next))) { + if (elm->area) + iopt_abort_area(elm->area); + if (elm->pages) + iopt_put_pages(elm->pages); + list_del(&elm->next); + kfree(elm); + } +} + +static int iopt_fill_domains_pages(struct list_head *pages_list) +{ + struct iopt_pages_list *undo_elm; + struct iopt_pages_list *elm; + int rc; + + list_for_each_entry(elm, pages_list, next) { + rc = iopt_area_fill_domains(elm->area, elm->pages); + if (rc) + goto err_undo; + } + return 0; + +err_undo: + list_for_each_entry(undo_elm, pages_list, next) { + if (undo_elm == elm) + break; + iopt_area_unfill_domains(undo_elm->area, undo_elm->pages); + } + return rc; +} + +int iopt_map_pages(struct io_pagetable *iopt, struct list_head *pages_list, + unsigned long length, unsigned long *dst_iova, + int iommu_prot, unsigned int flags) +{ + struct iopt_pages_list *elm; + int rc; + + rc = iopt_alloc_area_pages(iopt, pages_list, length, dst_iova, + iommu_prot, flags); + if (rc) + return rc; + + down_read(&iopt->domains_rwsem); + rc = iopt_fill_domains_pages(pages_list); + if (rc) + goto out_unlock_domains; + + down_write(&iopt->iova_rwsem); + list_for_each_entry(elm, pages_list, next) { + /* + * area->pages must be set inside the domains_rwsem to ensure + * any newly added domains will get filled. Moves the reference + * in from the list. + */ + elm->area->pages = elm->pages; + elm->pages = NULL; + elm->area = NULL; + } + up_write(&iopt->iova_rwsem); +out_unlock_domains: + up_read(&iopt->domains_rwsem); + return rc; +} + +/** + * iopt_map_user_pages() - Map a user VA to an iova in the io page table + * @ictx: iommufd_ctx the iopt is part of + * @iopt: io_pagetable to act on + * @iova: If IOPT_ALLOC_IOVA is set this is unused on input and contains + * the chosen iova on output. Otherwise is the iova to map to on input + * @uptr: User VA to map + * @length: Number of bytes to map + * @iommu_prot: Combination of IOMMU_READ/WRITE/etc bits for the mapping + * @flags: IOPT_ALLOC_IOVA or zero + * + * iova, uptr, and length must be aligned to iova_alignment. For domain backed + * page tables this will pin the pages and load them into the domain at iova. + * For non-domain page tables this will only setup a lazy reference and the + * caller must use iopt_access_pages() to touch them. + * + * iopt_unmap_iova() must be called to undo this before the io_pagetable can be + * destroyed. + */ +int iopt_map_user_pages(struct iommufd_ctx *ictx, struct io_pagetable *iopt, + unsigned long *iova, void __user *uptr, + unsigned long length, int iommu_prot, + unsigned int flags) +{ + struct iopt_pages_list elm = {}; + LIST_HEAD(pages_list); + int rc; + + elm.pages = iopt_alloc_pages(uptr, length, iommu_prot & IOMMU_WRITE); + if (IS_ERR(elm.pages)) + return PTR_ERR(elm.pages); + if (ictx->account_mode == IOPT_PAGES_ACCOUNT_MM && + elm.pages->account_mode == IOPT_PAGES_ACCOUNT_USER) + elm.pages->account_mode = IOPT_PAGES_ACCOUNT_MM; + elm.start_byte = uptr - elm.pages->uptr; + elm.length = length; + list_add(&elm.next, &pages_list); + + rc = iopt_map_pages(iopt, &pages_list, length, iova, iommu_prot, flags); + if (rc) { + if (elm.area) + iopt_abort_area(elm.area); + if (elm.pages) + iopt_put_pages(elm.pages); + return rc; + } + return 0; +} + +int iopt_get_pages(struct io_pagetable *iopt, unsigned long iova, + unsigned long length, struct list_head *pages_list) +{ + struct iopt_area_contig_iter iter; + unsigned long last_iova; + struct iopt_area *area; + int rc; + + if (!length) + return -EINVAL; + if (check_add_overflow(iova, length - 1, &last_iova)) + return -EOVERFLOW; + + down_read(&iopt->iova_rwsem); + iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) { + struct iopt_pages_list *elm; + unsigned long last = min(last_iova, iopt_area_last_iova(area)); + + elm = kzalloc(sizeof(*elm), GFP_KERNEL_ACCOUNT); + if (!elm) { + rc = -ENOMEM; + goto err_free; + } + elm->start_byte = iopt_area_start_byte(area, iter.cur_iova); + elm->pages = area->pages; + elm->length = (last - iter.cur_iova) + 1; + kref_get(&elm->pages->kref); + list_add_tail(&elm->next, pages_list); + } + if (!iopt_area_contig_done(&iter)) { + rc = -ENOENT; + goto err_free; + } + up_read(&iopt->iova_rwsem); + return 0; +err_free: + up_read(&iopt->iova_rwsem); + iopt_free_pages_list(pages_list); + return rc; +} + +static int iopt_unmap_iova_range(struct io_pagetable *iopt, unsigned long start, + unsigned long last, unsigned long *unmapped) +{ + struct iopt_area *area; + unsigned long unmapped_bytes = 0; + unsigned int tries = 0; + int rc = -ENOENT; + + /* + * The domains_rwsem must be held in read mode any time any area->pages + * is NULL. This prevents domain attach/detatch from running + * concurrently with cleaning up the area. + */ +again: + down_read(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + while ((area = iopt_area_iter_first(iopt, start, last))) { + unsigned long area_last = iopt_area_last_iova(area); + unsigned long area_first = iopt_area_iova(area); + struct iopt_pages *pages; + + /* Userspace should not race map/unmap's of the same area */ + if (!area->pages) { + rc = -EBUSY; + goto out_unlock_iova; + } + + if (area_first < start || area_last > last) { + rc = -ENOENT; + goto out_unlock_iova; + } + + if (area_first != start) + tries = 0; + + /* + * num_accesses writers must hold the iova_rwsem too, so we can + * safely read it under the write side of the iovam_rwsem + * without the pages->mutex. + */ + if (area->num_accesses) { + size_t length = iopt_area_length(area); + + start = area_first; + area->prevent_access = true; + up_write(&iopt->iova_rwsem); + up_read(&iopt->domains_rwsem); + + iommufd_access_notify_unmap(iopt, area_first, length); + /* Something is not responding to unmap requests. */ + tries++; + if (WARN_ON(tries > 100)) + return -EDEADLOCK; + goto again; + } + + pages = area->pages; + area->pages = NULL; + up_write(&iopt->iova_rwsem); + + iopt_area_unfill_domains(area, pages); + iopt_abort_area(area); + iopt_put_pages(pages); + + unmapped_bytes += area_last - area_first + 1; + + down_write(&iopt->iova_rwsem); + } + if (unmapped_bytes) + rc = 0; + +out_unlock_iova: + up_write(&iopt->iova_rwsem); + up_read(&iopt->domains_rwsem); + if (unmapped) + *unmapped = unmapped_bytes; + return rc; +} + +/** + * iopt_unmap_iova() - Remove a range of iova + * @iopt: io_pagetable to act on + * @iova: Starting iova to unmap + * @length: Number of bytes to unmap + * @unmapped: Return number of bytes unmapped + * + * The requested range must be a superset of existing ranges. + * Splitting/truncating IOVA mappings is not allowed. + */ +int iopt_unmap_iova(struct io_pagetable *iopt, unsigned long iova, + unsigned long length, unsigned long *unmapped) +{ + unsigned long iova_last; + + if (!length) + return -EINVAL; + + if (check_add_overflow(iova, length - 1, &iova_last)) + return -EOVERFLOW; + + return iopt_unmap_iova_range(iopt, iova, iova_last, unmapped); +} + +int iopt_unmap_all(struct io_pagetable *iopt, unsigned long *unmapped) +{ + int rc; + + rc = iopt_unmap_iova_range(iopt, 0, ULONG_MAX, unmapped); + /* If the IOVAs are empty then unmap all succeeds */ + if (rc == -ENOENT) + return 0; + return rc; +} + +/* The caller must always free all the nodes in the allowed_iova rb_root. */ +int iopt_set_allow_iova(struct io_pagetable *iopt, + struct rb_root_cached *allowed_iova) +{ + struct iopt_allowed *allowed; + + down_write(&iopt->iova_rwsem); + swap(*allowed_iova, iopt->allowed_itree); + + for (allowed = iopt_allowed_iter_first(iopt, 0, ULONG_MAX); allowed; + allowed = iopt_allowed_iter_next(allowed, 0, ULONG_MAX)) { + if (iopt_reserved_iter_first(iopt, allowed->node.start, + allowed->node.last)) { + swap(*allowed_iova, iopt->allowed_itree); + up_write(&iopt->iova_rwsem); + return -EADDRINUSE; + } + } + up_write(&iopt->iova_rwsem); + return 0; +} + +int iopt_reserve_iova(struct io_pagetable *iopt, unsigned long start, + unsigned long last, void *owner) +{ + struct iopt_reserved *reserved; + + lockdep_assert_held_write(&iopt->iova_rwsem); + + if (iopt_area_iter_first(iopt, start, last) || + iopt_allowed_iter_first(iopt, start, last)) + return -EADDRINUSE; + + reserved = kzalloc(sizeof(*reserved), GFP_KERNEL_ACCOUNT); + if (!reserved) + return -ENOMEM; + reserved->node.start = start; + reserved->node.last = last; + reserved->owner = owner; + interval_tree_insert(&reserved->node, &iopt->reserved_itree); + return 0; +} + +static void __iopt_remove_reserved_iova(struct io_pagetable *iopt, void *owner) +{ + struct iopt_reserved *reserved, *next; + + lockdep_assert_held_write(&iopt->iova_rwsem); + + for (reserved = iopt_reserved_iter_first(iopt, 0, ULONG_MAX); reserved; + reserved = next) { + next = iopt_reserved_iter_next(reserved, 0, ULONG_MAX); + + if (reserved->owner == owner) { + interval_tree_remove(&reserved->node, + &iopt->reserved_itree); + kfree(reserved); + } + } +} + +void iopt_remove_reserved_iova(struct io_pagetable *iopt, void *owner) +{ + down_write(&iopt->iova_rwsem); + __iopt_remove_reserved_iova(iopt, owner); + up_write(&iopt->iova_rwsem); +} + +void iopt_init_table(struct io_pagetable *iopt) +{ + init_rwsem(&iopt->iova_rwsem); + init_rwsem(&iopt->domains_rwsem); + iopt->area_itree = RB_ROOT_CACHED; + iopt->allowed_itree = RB_ROOT_CACHED; + iopt->reserved_itree = RB_ROOT_CACHED; + xa_init_flags(&iopt->domains, XA_FLAGS_ACCOUNT); + xa_init_flags(&iopt->access_list, XA_FLAGS_ALLOC); + + /* + * iopt's start as SW tables that can use the entire size_t IOVA space + * due to the use of size_t in the APIs. They have no alignment + * restriction. + */ + iopt->iova_alignment = 1; +} + +void iopt_destroy_table(struct io_pagetable *iopt) +{ + struct interval_tree_node *node; + + if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) + iopt_remove_reserved_iova(iopt, NULL); + + while ((node = interval_tree_iter_first(&iopt->allowed_itree, 0, + ULONG_MAX))) { + interval_tree_remove(node, &iopt->allowed_itree); + kfree(container_of(node, struct iopt_allowed, node)); + } + + WARN_ON(!RB_EMPTY_ROOT(&iopt->reserved_itree.rb_root)); + WARN_ON(!xa_empty(&iopt->domains)); + WARN_ON(!xa_empty(&iopt->access_list)); + WARN_ON(!RB_EMPTY_ROOT(&iopt->area_itree.rb_root)); +} + +/** + * iopt_unfill_domain() - Unfill a domain with PFNs + * @iopt: io_pagetable to act on + * @domain: domain to unfill + * + * This is used when removing a domain from the iopt. Every area in the iopt + * will be unmapped from the domain. The domain must already be removed from the + * domains xarray. + */ +static void iopt_unfill_domain(struct io_pagetable *iopt, + struct iommu_domain *domain) +{ + struct iopt_area *area; + + lockdep_assert_held(&iopt->iova_rwsem); + lockdep_assert_held_write(&iopt->domains_rwsem); + + /* + * Some other domain is holding all the pfns still, rapidly unmap this + * domain. + */ + if (iopt->next_domain_id != 0) { + /* Pick an arbitrary remaining domain to act as storage */ + struct iommu_domain *storage_domain = + xa_load(&iopt->domains, 0); + + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area; + area = iopt_area_iter_next(area, 0, ULONG_MAX)) { + struct iopt_pages *pages = area->pages; + + if (!pages) + continue; + + mutex_lock(&pages->mutex); + if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) + WARN_ON(!area->storage_domain); + if (area->storage_domain == domain) + area->storage_domain = storage_domain; + mutex_unlock(&pages->mutex); + + iopt_area_unmap_domain(area, domain); + } + return; + } + + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area; + area = iopt_area_iter_next(area, 0, ULONG_MAX)) { + struct iopt_pages *pages = area->pages; + + if (!pages) + continue; + + mutex_lock(&pages->mutex); + interval_tree_remove(&area->pages_node, &pages->domains_itree); + WARN_ON(area->storage_domain != domain); + area->storage_domain = NULL; + iopt_area_unfill_domain(area, pages, domain); + mutex_unlock(&pages->mutex); + } +} + +/** + * iopt_fill_domain() - Fill a domain with PFNs + * @iopt: io_pagetable to act on + * @domain: domain to fill + * + * Fill the domain with PFNs from every area in the iopt. On failure the domain + * is left unchanged. + */ +static int iopt_fill_domain(struct io_pagetable *iopt, + struct iommu_domain *domain) +{ + struct iopt_area *end_area; + struct iopt_area *area; + int rc; + + lockdep_assert_held(&iopt->iova_rwsem); + lockdep_assert_held_write(&iopt->domains_rwsem); + + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area; + area = iopt_area_iter_next(area, 0, ULONG_MAX)) { + struct iopt_pages *pages = area->pages; + + if (!pages) + continue; + + mutex_lock(&pages->mutex); + rc = iopt_area_fill_domain(area, domain); + if (rc) { + mutex_unlock(&pages->mutex); + goto out_unfill; + } + if (!area->storage_domain) { + WARN_ON(iopt->next_domain_id != 0); + area->storage_domain = domain; + interval_tree_insert(&area->pages_node, + &pages->domains_itree); + } + mutex_unlock(&pages->mutex); + } + return 0; + +out_unfill: + end_area = area; + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area; + area = iopt_area_iter_next(area, 0, ULONG_MAX)) { + struct iopt_pages *pages = area->pages; + + if (area == end_area) + break; + if (!pages) + continue; + mutex_lock(&pages->mutex); + if (iopt->next_domain_id == 0) { + interval_tree_remove(&area->pages_node, + &pages->domains_itree); + area->storage_domain = NULL; + } + iopt_area_unfill_domain(area, pages, domain); + mutex_unlock(&pages->mutex); + } + return rc; +} + +/* All existing area's conform to an increased page size */ +static int iopt_check_iova_alignment(struct io_pagetable *iopt, + unsigned long new_iova_alignment) +{ + unsigned long align_mask = new_iova_alignment - 1; + struct iopt_area *area; + + lockdep_assert_held(&iopt->iova_rwsem); + lockdep_assert_held(&iopt->domains_rwsem); + + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area; + area = iopt_area_iter_next(area, 0, ULONG_MAX)) + if ((iopt_area_iova(area) & align_mask) || + (iopt_area_length(area) & align_mask) || + (area->page_offset & align_mask)) + return -EADDRINUSE; + + if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) { + struct iommufd_access *access; + unsigned long index; + + xa_for_each(&iopt->access_list, index, access) + if (WARN_ON(access->iova_alignment > + new_iova_alignment)) + return -EADDRINUSE; + } + return 0; +} + +int iopt_table_add_domain(struct io_pagetable *iopt, + struct iommu_domain *domain) +{ + const struct iommu_domain_geometry *geometry = &domain->geometry; + struct iommu_domain *iter_domain; + unsigned int new_iova_alignment; + unsigned long index; + int rc; + + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + + xa_for_each(&iopt->domains, index, iter_domain) { + if (WARN_ON(iter_domain == domain)) { + rc = -EEXIST; + goto out_unlock; + } + } + + /* + * The io page size drives the iova_alignment. Internally the iopt_pages + * works in PAGE_SIZE units and we adjust when mapping sub-PAGE_SIZE + * objects into the iommu_domain. + * + * A iommu_domain must always be able to accept PAGE_SIZE to be + * compatible as we can't guarantee higher contiguity. + */ + new_iova_alignment = max_t(unsigned long, + 1UL << __ffs(domain->pgsize_bitmap), + iopt->iova_alignment); + if (new_iova_alignment > PAGE_SIZE) { + rc = -EINVAL; + goto out_unlock; + } + if (new_iova_alignment != iopt->iova_alignment) { + rc = iopt_check_iova_alignment(iopt, new_iova_alignment); + if (rc) + goto out_unlock; + } + + /* No area exists that is outside the allowed domain aperture */ + if (geometry->aperture_start != 0) { + rc = iopt_reserve_iova(iopt, 0, geometry->aperture_start - 1, + domain); + if (rc) + goto out_reserved; + } + if (geometry->aperture_end != ULONG_MAX) { + rc = iopt_reserve_iova(iopt, geometry->aperture_end + 1, + ULONG_MAX, domain); + if (rc) + goto out_reserved; + } + + rc = xa_reserve(&iopt->domains, iopt->next_domain_id, GFP_KERNEL); + if (rc) + goto out_reserved; + + rc = iopt_fill_domain(iopt, domain); + if (rc) + goto out_release; + + iopt->iova_alignment = new_iova_alignment; + xa_store(&iopt->domains, iopt->next_domain_id, domain, GFP_KERNEL); + iopt->next_domain_id++; + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); + return 0; +out_release: + xa_release(&iopt->domains, iopt->next_domain_id); +out_reserved: + __iopt_remove_reserved_iova(iopt, domain); +out_unlock: + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); + return rc; +} + +static int iopt_calculate_iova_alignment(struct io_pagetable *iopt) +{ + unsigned long new_iova_alignment; + struct iommufd_access *access; + struct iommu_domain *domain; + unsigned long index; + + lockdep_assert_held_write(&iopt->iova_rwsem); + lockdep_assert_held(&iopt->domains_rwsem); + + /* See batch_iommu_map_small() */ + if (iopt->disable_large_pages) + new_iova_alignment = PAGE_SIZE; + else + new_iova_alignment = 1; + + xa_for_each(&iopt->domains, index, domain) + new_iova_alignment = max_t(unsigned long, + 1UL << __ffs(domain->pgsize_bitmap), + new_iova_alignment); + xa_for_each(&iopt->access_list, index, access) + new_iova_alignment = max_t(unsigned long, + access->iova_alignment, + new_iova_alignment); + + if (new_iova_alignment > iopt->iova_alignment) { + int rc; + + rc = iopt_check_iova_alignment(iopt, new_iova_alignment); + if (rc) + return rc; + } + iopt->iova_alignment = new_iova_alignment; + return 0; +} + +void iopt_table_remove_domain(struct io_pagetable *iopt, + struct iommu_domain *domain) +{ + struct iommu_domain *iter_domain = NULL; + unsigned long index; + + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + + xa_for_each(&iopt->domains, index, iter_domain) + if (iter_domain == domain) + break; + if (WARN_ON(iter_domain != domain) || index >= iopt->next_domain_id) + goto out_unlock; + + /* + * Compress the xarray to keep it linear by swapping the entry to erase + * with the tail entry and shrinking the tail. + */ + iopt->next_domain_id--; + iter_domain = xa_erase(&iopt->domains, iopt->next_domain_id); + if (index != iopt->next_domain_id) + xa_store(&iopt->domains, index, iter_domain, GFP_KERNEL); + + iopt_unfill_domain(iopt, domain); + __iopt_remove_reserved_iova(iopt, domain); + + WARN_ON(iopt_calculate_iova_alignment(iopt)); +out_unlock: + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); +} + +/** + * iopt_area_split - Split an area into two parts at iova + * @area: The area to split + * @iova: Becomes the last of a new area + * + * This splits an area into two. It is part of the VFIO compatibility to allow + * poking a hole in the mapping. The two areas continue to point at the same + * iopt_pages, just with different starting bytes. + */ +static int iopt_area_split(struct iopt_area *area, unsigned long iova) +{ + unsigned long alignment = area->iopt->iova_alignment; + unsigned long last_iova = iopt_area_last_iova(area); + unsigned long start_iova = iopt_area_iova(area); + unsigned long new_start = iova + 1; + struct io_pagetable *iopt = area->iopt; + struct iopt_pages *pages = area->pages; + struct iopt_area *lhs; + struct iopt_area *rhs; + int rc; + + lockdep_assert_held_write(&iopt->iova_rwsem); + + if (iova == start_iova || iova == last_iova) + return 0; + + if (!pages || area->prevent_access) + return -EBUSY; + + if (new_start & (alignment - 1) || + iopt_area_start_byte(area, new_start) & (alignment - 1)) + return -EINVAL; + + lhs = iopt_area_alloc(); + if (!lhs) + return -ENOMEM; + + rhs = iopt_area_alloc(); + if (!rhs) { + rc = -ENOMEM; + goto err_free_lhs; + } + + mutex_lock(&pages->mutex); + /* + * Splitting is not permitted if an access exists, we don't track enough + * information to split existing accesses. + */ + if (area->num_accesses) { + rc = -EINVAL; + goto err_unlock; + } + + /* + * Splitting is not permitted if a domain could have been mapped with + * huge pages. + */ + if (area->storage_domain && !iopt->disable_large_pages) { + rc = -EINVAL; + goto err_unlock; + } + + interval_tree_remove(&area->node, &iopt->area_itree); + rc = iopt_insert_area(iopt, lhs, area->pages, start_iova, + iopt_area_start_byte(area, start_iova), + (new_start - 1) - start_iova + 1, + area->iommu_prot); + if (WARN_ON(rc)) + goto err_insert; + + rc = iopt_insert_area(iopt, rhs, area->pages, new_start, + iopt_area_start_byte(area, new_start), + last_iova - new_start + 1, area->iommu_prot); + if (WARN_ON(rc)) + goto err_remove_lhs; + + /* + * If the original area has filled a domain, domains_itree has to be + * updated. + */ + if (area->storage_domain) { + interval_tree_remove(&area->pages_node, &pages->domains_itree); + interval_tree_insert(&lhs->pages_node, &pages->domains_itree); + interval_tree_insert(&rhs->pages_node, &pages->domains_itree); + } + + lhs->storage_domain = area->storage_domain; + lhs->pages = area->pages; + rhs->storage_domain = area->storage_domain; + rhs->pages = area->pages; + kref_get(&rhs->pages->kref); + kfree(area); + mutex_unlock(&pages->mutex); + + /* + * No change to domains or accesses because the pages hasn't been + * changed + */ + return 0; + +err_remove_lhs: + interval_tree_remove(&lhs->node, &iopt->area_itree); +err_insert: + interval_tree_insert(&area->node, &iopt->area_itree); +err_unlock: + mutex_unlock(&pages->mutex); + kfree(rhs); +err_free_lhs: + kfree(lhs); + return rc; +} + +int iopt_cut_iova(struct io_pagetable *iopt, unsigned long *iovas, + size_t num_iovas) +{ + int rc = 0; + int i; + + down_write(&iopt->iova_rwsem); + for (i = 0; i < num_iovas; i++) { + struct iopt_area *area; + + area = iopt_area_iter_first(iopt, iovas[i], iovas[i]); + if (!area) + continue; + rc = iopt_area_split(area, iovas[i]); + if (rc) + break; + } + up_write(&iopt->iova_rwsem); + return rc; +} + +void iopt_enable_large_pages(struct io_pagetable *iopt) +{ + int rc; + + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + WRITE_ONCE(iopt->disable_large_pages, false); + rc = iopt_calculate_iova_alignment(iopt); + WARN_ON(rc); + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); +} + +int iopt_disable_large_pages(struct io_pagetable *iopt) +{ + int rc = 0; + + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + if (iopt->disable_large_pages) + goto out_unlock; + + /* Won't do it if domains already have pages mapped in them */ + if (!xa_empty(&iopt->domains) && + !RB_EMPTY_ROOT(&iopt->area_itree.rb_root)) { + rc = -EINVAL; + goto out_unlock; + } + + WRITE_ONCE(iopt->disable_large_pages, true); + rc = iopt_calculate_iova_alignment(iopt); + if (rc) + WRITE_ONCE(iopt->disable_large_pages, false); +out_unlock: + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); + return rc; +} + +int iopt_add_access(struct io_pagetable *iopt, struct iommufd_access *access) +{ + int rc; + + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + rc = xa_alloc(&iopt->access_list, &access->iopt_access_list_id, access, + xa_limit_16b, GFP_KERNEL_ACCOUNT); + if (rc) + goto out_unlock; + + rc = iopt_calculate_iova_alignment(iopt); + if (rc) { + xa_erase(&iopt->access_list, access->iopt_access_list_id); + goto out_unlock; + } + +out_unlock: + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); + return rc; +} + +void iopt_remove_access(struct io_pagetable *iopt, + struct iommufd_access *access, + u32 iopt_access_list_id) +{ + down_write(&iopt->domains_rwsem); + down_write(&iopt->iova_rwsem); + WARN_ON(xa_erase(&iopt->access_list, iopt_access_list_id) != access); + WARN_ON(iopt_calculate_iova_alignment(iopt)); + up_write(&iopt->iova_rwsem); + up_write(&iopt->domains_rwsem); +} + +/* Narrow the valid_iova_itree to include reserved ranges from a device. */ +int iopt_table_enforce_dev_resv_regions(struct io_pagetable *iopt, + struct device *dev, + phys_addr_t *sw_msi_start) +{ + struct iommu_resv_region *resv; + LIST_HEAD(resv_regions); + unsigned int num_hw_msi = 0; + unsigned int num_sw_msi = 0; + int rc; + + if (iommufd_should_fail()) + return -EINVAL; + + down_write(&iopt->iova_rwsem); + /* FIXME: drivers allocate memory but there is no failure propogated */ + iommu_get_resv_regions(dev, &resv_regions); + + list_for_each_entry(resv, &resv_regions, list) { + if (resv->type == IOMMU_RESV_DIRECT_RELAXABLE) + continue; + + if (sw_msi_start && resv->type == IOMMU_RESV_MSI) + num_hw_msi++; + if (sw_msi_start && resv->type == IOMMU_RESV_SW_MSI) { + *sw_msi_start = resv->start; + num_sw_msi++; + } + + rc = iopt_reserve_iova(iopt, resv->start, + resv->length - 1 + resv->start, dev); + if (rc) + goto out_reserved; + } + + /* Drivers must offer sane combinations of regions */ + if (WARN_ON(num_sw_msi && num_hw_msi) || WARN_ON(num_sw_msi > 1)) { + rc = -EINVAL; + goto out_reserved; + } + + rc = 0; + goto out_free_resv; + +out_reserved: + __iopt_remove_reserved_iova(iopt, dev); +out_free_resv: + iommu_put_resv_regions(dev, &resv_regions); + up_write(&iopt->iova_rwsem); + return rc; +} |