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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/errno.h>
- #include <linux/gfp.h>
- #include <linux/kernel.h>
- #include <linux/mm.h>
- #include <linux/memremap.h>
- #include <linux/slab.h>
- #include <asm/page.h>
- #include <xen/page.h>
- #include <xen/xen.h>
- static DEFINE_MUTEX(list_lock);
- static struct page *page_list;
- static unsigned int list_count;
- static int fill_list(unsigned int nr_pages)
- {
- struct dev_pagemap *pgmap;
- struct resource *res;
- void *vaddr;
- unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION);
- int ret = -ENOMEM;
- res = kzalloc(sizeof(*res), GFP_KERNEL);
- if (!res)
- return -ENOMEM;
- res->name = "Xen scratch";
- res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
- ret = allocate_resource(&iomem_resource, res,
- alloc_pages * PAGE_SIZE, 0, -1,
- PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
- if (ret < 0) {
- pr_err("Cannot allocate new IOMEM resource\n");
- goto err_resource;
- }
- pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL);
- if (!pgmap) {
- ret = -ENOMEM;
- goto err_pgmap;
- }
- pgmap->type = MEMORY_DEVICE_GENERIC;
- pgmap->range = (struct range) {
- .start = res->start,
- .end = res->end,
- };
- pgmap->nr_range = 1;
- pgmap->owner = res;
- #ifdef CONFIG_XEN_HAVE_PVMMU
- /*
- * memremap will build page tables for the new memory so
- * the p2m must contain invalid entries so the correct
- * non-present PTEs will be written.
- *
- * If a failure occurs, the original (identity) p2m entries
- * are not restored since this region is now known not to
- * conflict with any devices.
- */
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- xen_pfn_t pfn = PFN_DOWN(res->start);
- for (i = 0; i < alloc_pages; i++) {
- if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
- pr_warn("set_phys_to_machine() failed, no memory added\n");
- ret = -ENOMEM;
- goto err_memremap;
- }
- }
- }
- #endif
- vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
- if (IS_ERR(vaddr)) {
- pr_err("Cannot remap memory range\n");
- ret = PTR_ERR(vaddr);
- goto err_memremap;
- }
- for (i = 0; i < alloc_pages; i++) {
- struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
- BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));
- pg->zone_device_data = page_list;
- page_list = pg;
- list_count++;
- }
- return 0;
- err_memremap:
- kfree(pgmap);
- err_pgmap:
- release_resource(res);
- err_resource:
- kfree(res);
- return ret;
- }
- /**
- * xen_alloc_unpopulated_pages - alloc unpopulated pages
- * @nr_pages: Number of pages
- * @pages: pages returned
- * @return 0 on success, error otherwise
- */
- int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
- {
- unsigned int i;
- int ret = 0;
- mutex_lock(&list_lock);
- if (list_count < nr_pages) {
- ret = fill_list(nr_pages - list_count);
- if (ret)
- goto out;
- }
- for (i = 0; i < nr_pages; i++) {
- struct page *pg = page_list;
- BUG_ON(!pg);
- page_list = pg->zone_device_data;
- list_count--;
- pages[i] = pg;
- #ifdef CONFIG_XEN_HAVE_PVMMU
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- ret = xen_alloc_p2m_entry(page_to_pfn(pg));
- if (ret < 0) {
- unsigned int j;
- for (j = 0; j <= i; j++) {
- pages[j]->zone_device_data = page_list;
- page_list = pages[j];
- list_count++;
- }
- goto out;
- }
- }
- #endif
- }
- out:
- mutex_unlock(&list_lock);
- return ret;
- }
- EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
- /**
- * xen_free_unpopulated_pages - return unpopulated pages
- * @nr_pages: Number of pages
- * @pages: pages to return
- */
- void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
- {
- unsigned int i;
- mutex_lock(&list_lock);
- for (i = 0; i < nr_pages; i++) {
- pages[i]->zone_device_data = page_list;
- page_list = pages[i];
- list_count++;
- }
- mutex_unlock(&list_lock);
- }
- EXPORT_SYMBOL(xen_free_unpopulated_pages);
- #ifdef CONFIG_XEN_PV
- static int __init init(void)
- {
- unsigned int i;
- if (!xen_domain())
- return -ENODEV;
- if (!xen_pv_domain())
- return 0;
- /*
- * Initialize with pages from the extra memory regions (see
- * arch/x86/xen/setup.c).
- */
- for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
- unsigned int j;
- for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
- struct page *pg =
- pfn_to_page(xen_extra_mem[i].start_pfn + j);
- pg->zone_device_data = page_list;
- page_list = pg;
- list_count++;
- }
- }
- return 0;
- }
- subsys_initcall(init);
- #endif
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