1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
#ifdef VMAP_VIRT_START
#include <xen/bitmap.h>
#include <xen/cache.h>
#include <xen/init.h>
#include <xen/mm.h>
#include <xen/pfn.h>
#include <xen/spinlock.h>
#include <xen/types.h>
#include <xen/vmap.h>
#include <asm/page.h>
static DEFINE_SPINLOCK(vm_lock);
static void *__read_mostly vm_base;
#define vm_bitmap ((unsigned long *)vm_base)
/* highest allocated bit in the bitmap */
static unsigned int __read_mostly vm_top;
/* total number of bits in the bitmap */
static unsigned int __read_mostly vm_end;
/* lowest known clear bit in the bitmap */
static unsigned int vm_low;
void __init vm_init(void)
{
unsigned int i, nr;
unsigned long va;
vm_base = (void *)VMAP_VIRT_START;
vm_end = PFN_DOWN(arch_vmap_virt_end() - vm_base);
vm_low = PFN_UP((vm_end + 7) / 8);
nr = PFN_UP((vm_low + 7) / 8);
vm_top = nr * PAGE_SIZE * 8;
for ( i = 0, va = (unsigned long)vm_bitmap; i < nr; ++i, va += PAGE_SIZE )
{
struct page_info *pg = alloc_domheap_page(NULL, 0);
map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
clear_page((void *)va);
}
bitmap_fill(vm_bitmap, vm_low);
/* Populate page tables for the bitmap if necessary. */
map_pages_to_xen(va, 0, vm_low - nr, MAP_SMALL_PAGES);
}
void *vm_alloc(unsigned int nr, unsigned int align)
{
unsigned int start, bit;
if ( !align )
align = 1;
else if ( align & (align - 1) )
align &= -align;
spin_lock(&vm_lock);
for ( ; ; )
{
struct page_info *pg;
ASSERT(vm_low == vm_top || !test_bit(vm_low, vm_bitmap));
for ( start = vm_low; start < vm_top; )
{
bit = find_next_bit(vm_bitmap, vm_top, start + 1);
if ( bit > vm_top )
bit = vm_top;
/*
* Note that this skips the first bit, making the
* corresponding page a guard one.
*/
start = (start + align) & ~(align - 1);
if ( bit < vm_top )
{
if ( start + nr < bit )
break;
start = find_next_zero_bit(vm_bitmap, vm_top, bit + 1);
}
else
{
if ( start + nr <= bit )
break;
start = bit;
}
}
if ( start < vm_top )
break;
spin_unlock(&vm_lock);
if ( vm_top >= vm_end )
return NULL;
pg = alloc_domheap_page(NULL, 0);
if ( !pg )
return NULL;
spin_lock(&vm_lock);
if ( start >= vm_top )
{
unsigned long va = (unsigned long)vm_bitmap + vm_top / 8;
if ( !map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR) )
{
clear_page((void *)va);
vm_top += PAGE_SIZE * 8;
if ( vm_top > vm_end )
vm_top = vm_end;
continue;
}
}
free_domheap_page(pg);
if ( start >= vm_top )
{
spin_unlock(&vm_lock);
return NULL;
}
}
for ( bit = start; bit < start + nr; ++bit )
__set_bit(bit, vm_bitmap);
if ( bit < vm_top )
ASSERT(!test_bit(bit, vm_bitmap));
else
ASSERT(bit == vm_top);
if ( start <= vm_low + 2 )
vm_low = bit;
spin_unlock(&vm_lock);
return vm_base + start * PAGE_SIZE;
}
static unsigned int vm_index(const void *va)
{
unsigned long addr = (unsigned long)va & ~(PAGE_SIZE - 1);
unsigned int idx;
if ( addr < VMAP_VIRT_START + (vm_end / 8) ||
addr >= VMAP_VIRT_START + vm_top * PAGE_SIZE )
return 0;
idx = PFN_DOWN(va - vm_base);
return !test_bit(idx - 1, vm_bitmap) &&
test_bit(idx, vm_bitmap) ? idx : 0;
}
static unsigned int vm_size(const void *va)
{
unsigned int start = vm_index(va), end;
if ( !start )
return 0;
end = find_next_zero_bit(vm_bitmap, vm_top, start + 1);
return min(end, vm_top) - start;
}
void vm_free(const void *va)
{
unsigned int bit = vm_index(va);
if ( !bit )
{
WARN_ON(va != NULL);
return;
}
spin_lock(&vm_lock);
if ( bit < vm_low )
{
vm_low = bit - 1;
while ( !test_bit(vm_low - 1, vm_bitmap) )
--vm_low;
}
while ( __test_and_clear_bit(bit, vm_bitmap) )
if ( ++bit == vm_top )
break;
spin_unlock(&vm_lock);
}
void *__vmap(const unsigned long *mfn, unsigned int granularity,
unsigned int nr, unsigned int align, unsigned int flags)
{
void *va = vm_alloc(nr * granularity, align);
unsigned long cur = (unsigned long)va;
for ( ; va && nr--; ++mfn, cur += PAGE_SIZE * granularity )
{
if ( map_pages_to_xen(cur, *mfn, granularity, flags) )
{
vunmap(va);
va = NULL;
}
}
return va;
}
void *vmap(const unsigned long *mfn, unsigned int nr)
{
return __vmap(mfn, 1, nr, 1, PAGE_HYPERVISOR);
}
void vunmap(const void *va)
{
#ifndef _PAGE_NONE
unsigned long addr = (unsigned long)va;
destroy_xen_mappings(addr, addr + PAGE_SIZE * vm_size(va));
#else /* Avoid tearing down intermediate page tables. */
map_pages_to_xen((unsigned long)va, 0, vm_size(va), _PAGE_NONE);
#endif
vm_free(va);
}
#endif
|
