1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2024, Google LLC.
4 * Pasha Tatashin <pasha.tatashin@soleen.com>
5 */
6#include "iommu-pages.h"
7#include <linux/gfp.h>
8#include <linux/mm.h>
9
10#define IOPTDESC_MATCH(pg_elm, elm) \
11 static_assert(offsetof(struct page, pg_elm) == \
12 offsetof(struct ioptdesc, elm))
13IOPTDESC_MATCH(flags, __page_flags);
14IOPTDESC_MATCH(lru, iopt_freelist_elm); /* Ensure bit 0 is clear */
15IOPTDESC_MATCH(mapping, __page_mapping);
16IOPTDESC_MATCH(private, _private);
17IOPTDESC_MATCH(page_type, __page_type);
18IOPTDESC_MATCH(_refcount, __page_refcount);
19#ifdef CONFIG_MEMCG
20IOPTDESC_MATCH(memcg_data, memcg_data);
21#endif
22#undef IOPTDESC_MATCH
23static_assert(sizeof(struct ioptdesc) <= sizeof(struct page));
24
25/**
26 * iommu_alloc_pages_node_sz - Allocate a zeroed page of a given size from
27 * specific NUMA node
28 * @nid: memory NUMA node id
29 * @gfp: buddy allocator flags
30 * @size: Memory size to allocate, rounded up to a power of 2
31 *
32 * Returns the virtual address of the allocated page. The page must be freed
33 * either by calling iommu_free_pages() or via iommu_put_pages_list(). The
34 * returned allocation is round_up_pow_two(size) big, and is physically aligned
35 * to its size.
36 */
37void *iommu_alloc_pages_node_sz(int nid, gfp_t gfp, size_t size)
38{
39 unsigned long pgcnt;
40 struct folio *folio;
41 unsigned int order;
42
43 /* This uses page_address() on the memory. */
44 if (WARN_ON(gfp & __GFP_HIGHMEM))
45 return NULL;
46
47 /*
48 * Currently sub page allocations result in a full page being returned.
49 */
50 order = get_order(size);
51
52 /*
53 * __folio_alloc_node() does not handle NUMA_NO_NODE like
54 * alloc_pages_node() did.
55 */
56 if (nid == NUMA_NO_NODE)
57 nid = numa_mem_id();
58
59 folio = __folio_alloc_node(gfp | __GFP_ZERO, order, nid);
60 if (unlikely(!folio))
61 return NULL;
62
63 /*
64 * All page allocations that should be reported to as "iommu-pagetables"
65 * to userspace must use one of the functions below. This includes
66 * allocations of page-tables and other per-iommu_domain configuration
67 * structures.
68 *
69 * This is necessary for the proper accounting as IOMMU state can be
70 * rather large, i.e. multiple gigabytes in size.
71 */
72 pgcnt = 1UL << order;
73 mod_node_page_state(folio_pgdat(folio), NR_IOMMU_PAGES, pgcnt);
74 lruvec_stat_mod_folio(folio, idx: NR_SECONDARY_PAGETABLE, val: pgcnt);
75
76 return folio_address(folio);
77}
78EXPORT_SYMBOL_GPL(iommu_alloc_pages_node_sz);
79
80static void __iommu_free_desc(struct ioptdesc *iopt)
81{
82 struct folio *folio = ioptdesc_folio(iopt);
83 const unsigned long pgcnt = 1UL << folio_order(folio);
84
85 mod_node_page_state(folio_pgdat(folio), NR_IOMMU_PAGES, -pgcnt);
86 lruvec_stat_mod_folio(folio, idx: NR_SECONDARY_PAGETABLE, val: -pgcnt);
87 folio_put(folio);
88}
89
90/**
91 * iommu_free_pages - free pages
92 * @virt: virtual address of the page to be freed.
93 *
94 * The page must have have been allocated by iommu_alloc_pages_node_sz()
95 */
96void iommu_free_pages(void *virt)
97{
98 if (!virt)
99 return;
100 __iommu_free_desc(iopt: virt_to_ioptdesc(virt));
101}
102EXPORT_SYMBOL_GPL(iommu_free_pages);
103
104/**
105 * iommu_put_pages_list - free a list of pages.
106 * @list: The list of pages to be freed
107 *
108 * Frees a list of pages allocated by iommu_alloc_pages_node_sz(). On return the
109 * passed list is invalid, the caller must use IOMMU_PAGES_LIST_INIT to reinit
110 * the list if it expects to use it again.
111 */
112void iommu_put_pages_list(struct iommu_pages_list *list)
113{
114 struct ioptdesc *iopt, *tmp;
115
116 list_for_each_entry_safe(iopt, tmp, &list->pages, iopt_freelist_elm)
117 __iommu_free_desc(iopt);
118}
119EXPORT_SYMBOL_GPL(iommu_put_pages_list);
120