249 lines
5.5 KiB
C
249 lines
5.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/errno.h>
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#include <linux/gfp.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/memremap.h>
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#include <linux/slab.h>
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#include <asm/page.h>
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#include <xen/balloon.h>
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#include <xen/page.h>
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#include <xen/xen.h>
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static DEFINE_MUTEX(list_lock);
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static struct page *page_list;
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static unsigned int list_count;
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static struct resource *target_resource;
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/*
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* If arch is not happy with system "iomem_resource" being used for
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* the region allocation it can provide it's own view by creating specific
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* Xen resource with unused regions of guest physical address space provided
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* by the hypervisor.
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*/
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int __weak __init arch_xen_unpopulated_init(struct resource **res)
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{
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*res = &iomem_resource;
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return 0;
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}
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static int fill_list(unsigned int nr_pages)
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{
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struct dev_pagemap *pgmap;
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struct resource *res, *tmp_res = NULL;
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void *vaddr;
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unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION);
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struct range mhp_range;
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int ret;
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res = kzalloc(sizeof(*res), GFP_KERNEL);
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if (!res)
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return -ENOMEM;
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res->name = "Xen scratch";
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res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
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mhp_range = mhp_get_pluggable_range(true);
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ret = allocate_resource(target_resource, res,
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alloc_pages * PAGE_SIZE, mhp_range.start, mhp_range.end,
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PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
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if (ret < 0) {
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pr_err("Cannot allocate new IOMEM resource\n");
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goto err_resource;
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}
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/*
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* Reserve the region previously allocated from Xen resource to avoid
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* re-using it by someone else.
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*/
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if (target_resource != &iomem_resource) {
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tmp_res = kzalloc(sizeof(*tmp_res), GFP_KERNEL);
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if (!tmp_res) {
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ret = -ENOMEM;
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goto err_insert;
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}
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tmp_res->name = res->name;
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tmp_res->start = res->start;
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tmp_res->end = res->end;
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tmp_res->flags = res->flags;
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ret = request_resource(&iomem_resource, tmp_res);
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if (ret < 0) {
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pr_err("Cannot request resource %pR (%d)\n", tmp_res, ret);
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kfree(tmp_res);
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goto err_insert;
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}
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}
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pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL);
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if (!pgmap) {
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ret = -ENOMEM;
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goto err_pgmap;
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}
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pgmap->type = MEMORY_DEVICE_GENERIC;
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pgmap->range = (struct range) {
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.start = res->start,
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.end = res->end,
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};
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pgmap->nr_range = 1;
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pgmap->owner = res;
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#ifdef CONFIG_XEN_HAVE_PVMMU
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/*
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* memremap will build page tables for the new memory so
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* the p2m must contain invalid entries so the correct
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* non-present PTEs will be written.
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*
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* If a failure occurs, the original (identity) p2m entries
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* are not restored since this region is now known not to
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* conflict with any devices.
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*/
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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xen_pfn_t pfn = PFN_DOWN(res->start);
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for (i = 0; i < alloc_pages; i++) {
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if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
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pr_warn("set_phys_to_machine() failed, no memory added\n");
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ret = -ENOMEM;
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goto err_memremap;
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}
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}
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}
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#endif
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vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
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if (IS_ERR(vaddr)) {
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pr_err("Cannot remap memory range\n");
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ret = PTR_ERR(vaddr);
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goto err_memremap;
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}
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for (i = 0; i < alloc_pages; i++) {
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struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
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pg->zone_device_data = page_list;
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page_list = pg;
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list_count++;
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}
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return 0;
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err_memremap:
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kfree(pgmap);
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err_pgmap:
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if (tmp_res) {
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release_resource(tmp_res);
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kfree(tmp_res);
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}
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err_insert:
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release_resource(res);
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err_resource:
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kfree(res);
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return ret;
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}
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/**
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* xen_alloc_unpopulated_pages - alloc unpopulated pages
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* @nr_pages: Number of pages
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* @pages: pages returned
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* @return 0 on success, error otherwise
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*/
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int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
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{
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unsigned int i;
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int ret = 0;
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/*
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* Fallback to default behavior if we do not have any suitable resource
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* to allocate required region from and as the result we won't be able to
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* construct pages.
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*/
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if (!target_resource)
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return xen_alloc_ballooned_pages(nr_pages, pages);
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mutex_lock(&list_lock);
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if (list_count < nr_pages) {
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ret = fill_list(nr_pages - list_count);
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if (ret)
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goto out;
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}
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for (i = 0; i < nr_pages; i++) {
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struct page *pg = page_list;
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BUG_ON(!pg);
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page_list = pg->zone_device_data;
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list_count--;
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pages[i] = pg;
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#ifdef CONFIG_XEN_HAVE_PVMMU
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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ret = xen_alloc_p2m_entry(page_to_pfn(pg));
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if (ret < 0) {
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unsigned int j;
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for (j = 0; j <= i; j++) {
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pages[j]->zone_device_data = page_list;
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page_list = pages[j];
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list_count++;
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}
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goto out;
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}
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}
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#endif
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}
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out:
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mutex_unlock(&list_lock);
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return ret;
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}
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EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
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/**
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* xen_free_unpopulated_pages - return unpopulated pages
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* @nr_pages: Number of pages
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* @pages: pages to return
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*/
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void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
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{
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unsigned int i;
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if (!target_resource) {
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xen_free_ballooned_pages(nr_pages, pages);
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return;
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}
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mutex_lock(&list_lock);
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for (i = 0; i < nr_pages; i++) {
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pages[i]->zone_device_data = page_list;
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page_list = pages[i];
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list_count++;
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}
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mutex_unlock(&list_lock);
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}
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EXPORT_SYMBOL(xen_free_unpopulated_pages);
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static int __init unpopulated_init(void)
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{
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int ret;
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if (!xen_domain())
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return -ENODEV;
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ret = arch_xen_unpopulated_init(&target_resource);
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if (ret) {
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pr_err("xen:unpopulated: Cannot initialize target resource\n");
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target_resource = NULL;
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}
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return ret;
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}
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early_initcall(unpopulated_init);
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