1// SPDX-License-Identifier: GPL-2.0 OR MIT
2/******************************************************************************
3 * grant_table.c
4 * x86 specific part
5 *
6 * Granting foreign access to our memory reservation.
7 *
8 * Copyright (c) 2005-2006, Christopher Clark
9 * Copyright (c) 2004-2005, K A Fraser
10 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
11 *                    VA Linux Systems Japan. Split out x86 specific part.
12 */
13
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/slab.h>
17#include <linux/vmalloc.h>
18
19#include <xen/interface/xen.h>
20#include <xen/page.h>
21#include <xen/grant_table.h>
22#include <xen/xen.h>
23
24
25static struct gnttab_vm_area {
26	struct vm_struct *area;
27	pte_t **ptes;
28	int idx;
29} gnttab_shared_vm_area, gnttab_status_vm_area;
30
31int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
32			   unsigned long max_nr_gframes,
33			   void **__shared)
34{
35	void *shared = *__shared;
36	unsigned long addr;
37	unsigned long i;
38
39	if (shared == NULL)
40		*__shared = shared = gnttab_shared_vm_area.area->addr;
41
42	addr = (unsigned long)shared;
43
44	for (i = 0; i < nr_gframes; i++) {
45		set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
46			   mfn_pte(frames[i], PAGE_KERNEL));
47		addr += PAGE_SIZE;
48	}
49
50	return 0;
51}
52
53int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
54			   unsigned long max_nr_gframes,
55			   grant_status_t **__shared)
56{
57	grant_status_t *shared = *__shared;
58	unsigned long addr;
59	unsigned long i;
60
61	if (shared == NULL)
62		*__shared = shared = gnttab_status_vm_area.area->addr;
63
64	addr = (unsigned long)shared;
65
66	for (i = 0; i < nr_gframes; i++) {
67		set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
68			   mfn_pte(frames[i], PAGE_KERNEL));
69		addr += PAGE_SIZE;
70	}
71
72	return 0;
73}
74
75void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
76{
77	pte_t **ptes;
78	unsigned long addr;
79	unsigned long i;
80
81	if (shared == gnttab_status_vm_area.area->addr)
82		ptes = gnttab_status_vm_area.ptes;
83	else
84		ptes = gnttab_shared_vm_area.ptes;
85
86	addr = (unsigned long)shared;
87
88	for (i = 0; i < nr_gframes; i++) {
89		set_pte_at(&init_mm, addr, ptes[i], __pte(0));
90		addr += PAGE_SIZE;
91	}
92}
93
94static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
95{
96	struct gnttab_vm_area *area = data;
97
98	area->ptes[area->idx++] = pte;
99	return 0;
100}
101
102static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
103{
104	area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
105	if (area->ptes == NULL)
106		return -ENOMEM;
107	area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
108	if (!area->area)
109		goto out_free_ptes;
110	if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
111			PAGE_SIZE * nr_frames, gnttab_apply, area))
112		goto out_free_vm_area;
113	return 0;
114out_free_vm_area:
115	free_vm_area(area->area);
116out_free_ptes:
117	kfree(area->ptes);
118	return -ENOMEM;
119}
120
121static void arch_gnttab_vfree(struct gnttab_vm_area *area)
122{
123	free_vm_area(area->area);
124	kfree(area->ptes);
125}
126
127int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
128{
129	int ret;
130
131	if (!xen_pv_domain())
132		return 0;
133
134	ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
135	if (ret < 0)
136		return ret;
137
138	/*
139	 * Always allocate the space for the status frames in case
140	 * we're migrated to a host with V2 support.
141	 */
142	ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
143	if (ret < 0)
144		goto err;
145
146	return 0;
147err:
148	arch_gnttab_vfree(&gnttab_shared_vm_area);
149	return -ENOMEM;
150}
151
152#ifdef CONFIG_XEN_PVH
153#include <xen/events.h>
154#include <xen/xen-ops.h>
155static int __init xen_pvh_gnttab_setup(void)
156{
157	if (!xen_pvh_domain())
158		return -ENODEV;
159
160	xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
161
162	return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
163					     &xen_auto_xlat_grant_frames.vaddr,
164					     xen_auto_xlat_grant_frames.count);
165}
166/* Call it _before_ __gnttab_init as we need to initialize the
167 * xen_auto_xlat_grant_frames first. */
168core_initcall(xen_pvh_gnttab_setup);
169#endif
170