1/******************************************************************************
  2 * grant_table.c
  3 * x86 specific part
  4 *
  5 * Granting foreign access to our memory reservation.
  6 *
  7 * Copyright (c) 2005-2006, Christopher Clark
  8 * Copyright (c) 2004-2005, K A Fraser
  9 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
 10 *                    VA Linux Systems Japan. Split out x86 specific part.
 11 *
 12 * This program is free software; you can redistribute it and/or
 13 * modify it under the terms of the GNU General Public License version 2
 14 * as published by the Free Software Foundation; or, when distributed
 15 * separately from the Linux kernel or incorporated into other
 16 * software packages, subject to the following license:
 17 *
 18 * Permission is hereby granted, free of charge, to any person obtaining a copy
 19 * of this source file (the "Software"), to deal in the Software without
 20 * restriction, including without limitation the rights to use, copy, modify,
 21 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 22 * and to permit persons to whom the Software is furnished to do so, subject to
 23 * the following conditions:
 24 *
 25 * The above copyright notice and this permission notice shall be included in
 26 * all copies or substantial portions of the Software.
 27 *
 28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 29 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 30 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 31 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 32 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 33 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 34 * IN THE SOFTWARE.
 35 */
 36
 37#include <linux/sched.h>
 38#include <linux/mm.h>
 39#include <linux/vmalloc.h>
 40
 41#include <xen/interface/xen.h>
 42#include <xen/page.h>
 43#include <xen/grant_table.h>
 44
 45#include <asm/pgtable.h>
 46
 47static int map_pte_fn(pte_t *pte, struct page *pmd_page,
 48		      unsigned long addr, void *data)
 49{
 50	unsigned long **frames = (unsigned long **)data;
 51
 52	set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
 53	(*frames)++;
 54	return 0;
 55}
 56
 57/*
 58 * This function is used to map shared frames to store grant status. It is
 59 * different from map_pte_fn above, the frames type here is uint64_t.
 60 */
 61static int map_pte_fn_status(pte_t *pte, struct page *pmd_page,
 62			     unsigned long addr, void *data)
 63{
 64	uint64_t **frames = (uint64_t **)data;
 65
 66	set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
 67	(*frames)++;
 68	return 0;
 69}
 70
 71static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
 72			unsigned long addr, void *data)
 73{
 74
 75	set_pte_at(&init_mm, addr, pte, __pte(0));
 76	return 0;
 77}
 78
 79int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
 80			   unsigned long max_nr_gframes,
 81			   void **__shared)
 82{
 83	int rc;
 84	void *shared = *__shared;
 85
 86	if (shared == NULL) {
 87		struct vm_struct *area =
 88			alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
 89		BUG_ON(area == NULL);
 90		shared = area->addr;
 91		*__shared = shared;
 92	}
 93
 94	rc = apply_to_page_range(&init_mm, (unsigned long)shared,
 95				 PAGE_SIZE * nr_gframes,
 96				 map_pte_fn, &frames);
 97	return rc;
 98}
 99
100int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
101			   unsigned long max_nr_gframes,
102			   grant_status_t **__shared)
103{
104	int rc;
105	grant_status_t *shared = *__shared;
106
107	if (shared == NULL) {
108		/* No need to pass in PTE as we are going to do it
109		 * in apply_to_page_range anyhow. */
110		struct vm_struct *area =
111			alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
112		BUG_ON(area == NULL);
113		shared = area->addr;
114		*__shared = shared;
115	}
116
117	rc = apply_to_page_range(&init_mm, (unsigned long)shared,
118				 PAGE_SIZE * nr_gframes,
119				 map_pte_fn_status, &frames);
120	return rc;
121}
122
123void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
124{
125	apply_to_page_range(&init_mm, (unsigned long)shared,
126			    PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL);
127}