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
22struct xen_p2m_entry {
23	unsigned long pfn;
24	unsigned long mfn;
25	unsigned long nr_pages;
26	struct rb_node rbnode_phys;
27};
28
29static rwlock_t p2m_lock;
30struct rb_root phys_to_mach = RB_ROOT;
31EXPORT_SYMBOL_GPL(phys_to_mach);
32
33static 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
56err_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);
60out:
61	return rc;
62}
63
64unsigned 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}
89EXPORT_SYMBOL_GPL(__pfn_to_mfn);
90
91int 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
136int 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
150bool __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}
197EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
198
199bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
200{
201	return __set_phys_to_machine_multi(pfn, mfn, 1);
202}
203EXPORT_SYMBOL_GPL(__set_phys_to_machine);
204
205static int p2m_init(void)
206{
207	rwlock_init(&p2m_lock);
208	return 0;
209}
210arch_initcall(p2m_init);
211