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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | +#include <linux/errno.h> |
| 3 | +#include <linux/gfp.h> |
| 4 | +#include <linux/kernel.h> |
| 5 | +#include <linux/mm.h> |
| 6 | +#include <linux/memremap.h> |
| 7 | +#include <linux/slab.h> |
| 8 | + |
| 9 | +#include <asm/page.h> |
| 10 | + |
| 11 | +#include <xen/page.h> |
| 12 | +#include <xen/xen.h> |
| 13 | + |
| 14 | +static DEFINE_MUTEX(list_lock); |
| 15 | +static LIST_HEAD(page_list); |
| 16 | +static unsigned int list_count; |
| 17 | + |
| 18 | +static int fill_list(unsigned int nr_pages) |
| 19 | +{ |
| 20 | + struct dev_pagemap *pgmap; |
| 21 | + void *vaddr; |
| 22 | + unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); |
| 23 | + int ret; |
| 24 | + |
| 25 | + pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL); |
| 26 | + if (!pgmap) |
| 27 | + return -ENOMEM; |
| 28 | + |
| 29 | + pgmap->type = MEMORY_DEVICE_GENERIC; |
| 30 | + pgmap->res.name = "Xen scratch"; |
| 31 | + pgmap->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; |
| 32 | + |
| 33 | + ret = allocate_resource(&iomem_resource, &pgmap->res, |
| 34 | + alloc_pages * PAGE_SIZE, 0, -1, |
| 35 | + PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); |
| 36 | + if (ret < 0) { |
| 37 | + pr_err("Cannot allocate new IOMEM resource\n"); |
| 38 | + kfree(pgmap); |
| 39 | + return ret; |
| 40 | + } |
| 41 | + |
| 42 | +#ifdef CONFIG_XEN_HAVE_PVMMU |
| 43 | + /* |
| 44 | + * memremap will build page tables for the new memory so |
| 45 | + * the p2m must contain invalid entries so the correct |
| 46 | + * non-present PTEs will be written. |
| 47 | + * |
| 48 | + * If a failure occurs, the original (identity) p2m entries |
| 49 | + * are not restored since this region is now known not to |
| 50 | + * conflict with any devices. |
| 51 | + */ |
| 52 | + if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
| 53 | + xen_pfn_t pfn = PFN_DOWN(pgmap->res.start); |
| 54 | + |
| 55 | + for (i = 0; i < alloc_pages; i++) { |
| 56 | + if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { |
| 57 | + pr_warn("set_phys_to_machine() failed, no memory added\n"); |
| 58 | + release_resource(&pgmap->res); |
| 59 | + kfree(pgmap); |
| 60 | + return -ENOMEM; |
| 61 | + } |
| 62 | + } |
| 63 | + } |
| 64 | +#endif |
| 65 | + |
| 66 | + vaddr = memremap_pages(pgmap, NUMA_NO_NODE); |
| 67 | + if (IS_ERR(vaddr)) { |
| 68 | + pr_err("Cannot remap memory range\n"); |
| 69 | + release_resource(&pgmap->res); |
| 70 | + kfree(pgmap); |
| 71 | + return PTR_ERR(vaddr); |
| 72 | + } |
| 73 | + |
| 74 | + for (i = 0; i < alloc_pages; i++) { |
| 75 | + struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i); |
| 76 | + |
| 77 | + BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i)); |
| 78 | + list_add(&pg->lru, &page_list); |
| 79 | + list_count++; |
| 80 | + } |
| 81 | + |
| 82 | + return 0; |
| 83 | +} |
| 84 | + |
| 85 | +/** |
| 86 | + * xen_alloc_unpopulated_pages - alloc unpopulated pages |
| 87 | + * @nr_pages: Number of pages |
| 88 | + * @pages: pages returned |
| 89 | + * @return 0 on success, error otherwise |
| 90 | + */ |
| 91 | +int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) |
| 92 | +{ |
| 93 | + unsigned int i; |
| 94 | + int ret = 0; |
| 95 | + |
| 96 | + mutex_lock(&list_lock); |
| 97 | + if (list_count < nr_pages) { |
| 98 | + ret = fill_list(nr_pages - list_count); |
| 99 | + if (ret) |
| 100 | + goto out; |
| 101 | + } |
| 102 | + |
| 103 | + for (i = 0; i < nr_pages; i++) { |
| 104 | + struct page *pg = list_first_entry_or_null(&page_list, |
| 105 | + struct page, |
| 106 | + lru); |
| 107 | + |
| 108 | + BUG_ON(!pg); |
| 109 | + list_del(&pg->lru); |
| 110 | + list_count--; |
| 111 | + pages[i] = pg; |
| 112 | + |
| 113 | +#ifdef CONFIG_XEN_HAVE_PVMMU |
| 114 | + if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
| 115 | + ret = xen_alloc_p2m_entry(page_to_pfn(pg)); |
| 116 | + if (ret < 0) { |
| 117 | + unsigned int j; |
| 118 | + |
| 119 | + for (j = 0; j <= i; j++) { |
| 120 | + list_add(&pages[j]->lru, &page_list); |
| 121 | + list_count++; |
| 122 | + } |
| 123 | + goto out; |
| 124 | + } |
| 125 | + } |
| 126 | +#endif |
| 127 | + } |
| 128 | + |
| 129 | +out: |
| 130 | + mutex_unlock(&list_lock); |
| 131 | + return ret; |
| 132 | +} |
| 133 | +EXPORT_SYMBOL(xen_alloc_unpopulated_pages); |
| 134 | + |
| 135 | +/** |
| 136 | + * xen_free_unpopulated_pages - return unpopulated pages |
| 137 | + * @nr_pages: Number of pages |
| 138 | + * @pages: pages to return |
| 139 | + */ |
| 140 | +void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) |
| 141 | +{ |
| 142 | + unsigned int i; |
| 143 | + |
| 144 | + mutex_lock(&list_lock); |
| 145 | + for (i = 0; i < nr_pages; i++) { |
| 146 | + list_add(&pages[i]->lru, &page_list); |
| 147 | + list_count++; |
| 148 | + } |
| 149 | + mutex_unlock(&list_lock); |
| 150 | +} |
| 151 | +EXPORT_SYMBOL(xen_free_unpopulated_pages); |
| 152 | + |
| 153 | +#ifdef CONFIG_XEN_PV |
| 154 | +static int __init init(void) |
| 155 | +{ |
| 156 | + unsigned int i; |
| 157 | + |
| 158 | + if (!xen_domain()) |
| 159 | + return -ENODEV; |
| 160 | + |
| 161 | + if (!xen_pv_domain()) |
| 162 | + return 0; |
| 163 | + |
| 164 | + /* |
| 165 | + * Initialize with pages from the extra memory regions (see |
| 166 | + * arch/x86/xen/setup.c). |
| 167 | + */ |
| 168 | + for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { |
| 169 | + unsigned int j; |
| 170 | + |
| 171 | + for (j = 0; j < xen_extra_mem[i].n_pfns; j++) { |
| 172 | + struct page *pg = |
| 173 | + pfn_to_page(xen_extra_mem[i].start_pfn + j); |
| 174 | + |
| 175 | + list_add(&pg->lru, &page_list); |
| 176 | + list_count++; |
| 177 | + } |
| 178 | + } |
| 179 | + |
| 180 | + return 0; |
| 181 | +} |
| 182 | +subsys_initcall(init); |
| 183 | +#endif |
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