xref: /openbmc/linux/arch/x86/xen/grant-table.c (revision 5dd63bf1)
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 
25 static 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 
arch_gnttab_map_shared(unsigned long * frames,unsigned long nr_gframes,unsigned long max_nr_gframes,void ** __shared)31 int 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 
arch_gnttab_map_status(uint64_t * frames,unsigned long nr_gframes,unsigned long max_nr_gframes,grant_status_t ** __shared)53 int 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 
arch_gnttab_unmap(void * shared,unsigned long nr_gframes)75 void 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 
gnttab_apply(pte_t * pte,unsigned long addr,void * data)94 static 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 
arch_gnttab_valloc(struct gnttab_vm_area * area,unsigned nr_frames)102 static 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;
114 out_free_vm_area:
115 	free_vm_area(area->area);
116 out_free_ptes:
117 	kfree(area->ptes);
118 	return -ENOMEM;
119 }
120 
arch_gnttab_vfree(struct gnttab_vm_area * area)121 static void arch_gnttab_vfree(struct gnttab_vm_area *area)
122 {
123 	free_vm_area(area->area);
124 	kfree(area->ptes);
125 }
126 
arch_gnttab_init(unsigned long nr_shared,unsigned long nr_status)127 int 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;
147 err:
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>
xen_pvh_gnttab_setup(void)155 static 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. */
168 core_initcall(xen_pvh_gnttab_setup);
169 #endif
170