xref: /linux/arch/arm/xen/p2m.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/memblock.h>
3 #include <linux/gfp.h>
4 #include <linux/export.h>
5 #include <linux/spinlock.h>
6 #include <linux/slab.h>
7 #include <linux/types.h>
8 #include <linux/dma-mapping.h>
9 #include <linux/vmalloc.h>
10 #include <linux/swiotlb.h>
11 
12 #include <xen/xen.h>
13 #include <xen/interface/memory.h>
14 #include <xen/grant_table.h>
15 #include <xen/page.h>
16 #include <xen/swiotlb-xen.h>
17 
18 #include <asm/cacheflush.h>
19 #include <asm/xen/hypercall.h>
20 #include <asm/xen/interface.h>
21 
22 struct xen_p2m_entry {
23 	unsigned long pfn;
24 	unsigned long mfn;
25 	unsigned long nr_pages;
26 	struct rb_node rbnode_phys;
27 };
28 
29 static rwlock_t p2m_lock;
30 struct rb_root phys_to_mach = RB_ROOT;
31 EXPORT_SYMBOL_GPL(phys_to_mach);
32 
xen_add_phys_to_mach_entry(struct xen_p2m_entry * new)33 static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
34 {
35 	struct rb_node **link = &phys_to_mach.rb_node;
36 	struct rb_node *parent = NULL;
37 	struct xen_p2m_entry *entry;
38 	int rc = 0;
39 
40 	while (*link) {
41 		parent = *link;
42 		entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
43 
44 		if (new->pfn == entry->pfn)
45 			goto err_out;
46 
47 		if (new->pfn < entry->pfn)
48 			link = &(*link)->rb_left;
49 		else
50 			link = &(*link)->rb_right;
51 	}
52 	rb_link_node(&new->rbnode_phys, parent, link);
53 	rb_insert_color(&new->rbnode_phys, &phys_to_mach);
54 	goto out;
55 
56 err_out:
57 	rc = -EINVAL;
58 	pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
59 			__func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
60 out:
61 	return rc;
62 }
63 
__pfn_to_mfn(unsigned long pfn)64 unsigned long __pfn_to_mfn(unsigned long pfn)
65 {
66 	struct rb_node *n;
67 	struct xen_p2m_entry *entry;
68 	unsigned long irqflags;
69 
70 	read_lock_irqsave(&p2m_lock, irqflags);
71 	n = phys_to_mach.rb_node;
72 	while (n) {
73 		entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
74 		if (entry->pfn <= pfn &&
75 				entry->pfn + entry->nr_pages > pfn) {
76 			unsigned long mfn = entry->mfn + (pfn - entry->pfn);
77 			read_unlock_irqrestore(&p2m_lock, irqflags);
78 			return mfn;
79 		}
80 		if (pfn < entry->pfn)
81 			n = n->rb_left;
82 		else
83 			n = n->rb_right;
84 	}
85 	read_unlock_irqrestore(&p2m_lock, irqflags);
86 
87 	return INVALID_P2M_ENTRY;
88 }
89 EXPORT_SYMBOL_GPL(__pfn_to_mfn);
90 
set_foreign_p2m_mapping(struct gnttab_map_grant_ref * map_ops,struct gnttab_map_grant_ref * kmap_ops,struct page ** pages,unsigned int count)91 int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
92 			    struct gnttab_map_grant_ref *kmap_ops,
93 			    struct page **pages, unsigned int count)
94 {
95 	int i;
96 
97 	for (i = 0; i < count; i++) {
98 		struct gnttab_unmap_grant_ref unmap;
99 		int rc;
100 
101 		if (map_ops[i].status)
102 			continue;
103 		if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
104 				    map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
105 			continue;
106 
107 		/*
108 		 * Signal an error for this slot. This in turn requires
109 		 * immediate unmapping.
110 		 */
111 		map_ops[i].status = GNTST_general_error;
112 		unmap.host_addr = map_ops[i].host_addr;
113 		unmap.handle = map_ops[i].handle;
114 		map_ops[i].handle = INVALID_GRANT_HANDLE;
115 		if (map_ops[i].flags & GNTMAP_device_map)
116 			unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
117 		else
118 			unmap.dev_bus_addr = 0;
119 
120 		/*
121 		 * Pre-populate the status field, to be recognizable in
122 		 * the log message below.
123 		 */
124 		unmap.status = 1;
125 
126 		rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
127 					       &unmap, 1);
128 		if (rc || unmap.status != GNTST_okay)
129 			pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
130 				    rc, unmap.status);
131 	}
132 
133 	return 0;
134 }
135 
clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref * unmap_ops,struct gnttab_unmap_grant_ref * kunmap_ops,struct page ** pages,unsigned int count)136 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
137 			      struct gnttab_unmap_grant_ref *kunmap_ops,
138 			      struct page **pages, unsigned int count)
139 {
140 	int i;
141 
142 	for (i = 0; i < count; i++) {
143 		set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
144 				    INVALID_P2M_ENTRY);
145 	}
146 
147 	return 0;
148 }
149 
__set_phys_to_machine_multi(unsigned long pfn,unsigned long mfn,unsigned long nr_pages)150 bool __set_phys_to_machine_multi(unsigned long pfn,
151 		unsigned long mfn, unsigned long nr_pages)
152 {
153 	int rc;
154 	unsigned long irqflags;
155 	struct xen_p2m_entry *p2m_entry;
156 	struct rb_node *n;
157 
158 	if (mfn == INVALID_P2M_ENTRY) {
159 		write_lock_irqsave(&p2m_lock, irqflags);
160 		n = phys_to_mach.rb_node;
161 		while (n) {
162 			p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
163 			if (p2m_entry->pfn <= pfn &&
164 					p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
165 				rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
166 				write_unlock_irqrestore(&p2m_lock, irqflags);
167 				kfree(p2m_entry);
168 				return true;
169 			}
170 			if (pfn < p2m_entry->pfn)
171 				n = n->rb_left;
172 			else
173 				n = n->rb_right;
174 		}
175 		write_unlock_irqrestore(&p2m_lock, irqflags);
176 		return true;
177 	}
178 
179 	p2m_entry = kzalloc(sizeof(*p2m_entry), GFP_NOWAIT);
180 	if (!p2m_entry)
181 		return false;
182 
183 	p2m_entry->pfn = pfn;
184 	p2m_entry->nr_pages = nr_pages;
185 	p2m_entry->mfn = mfn;
186 
187 	write_lock_irqsave(&p2m_lock, irqflags);
188 	rc = xen_add_phys_to_mach_entry(p2m_entry);
189 	if (rc < 0) {
190 		write_unlock_irqrestore(&p2m_lock, irqflags);
191 		kfree(p2m_entry);
192 		return false;
193 	}
194 	write_unlock_irqrestore(&p2m_lock, irqflags);
195 	return true;
196 }
197 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
198 
__set_phys_to_machine(unsigned long pfn,unsigned long mfn)199 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
200 {
201 	return __set_phys_to_machine_multi(pfn, mfn, 1);
202 }
203 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
204 
p2m_init(void)205 static int p2m_init(void)
206 {
207 	rwlock_init(&p2m_lock);
208 	return 0;
209 }
210 arch_initcall(p2m_init);
211