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
|
/******************************************************************************
* include/asm-x86/mem_sharing.h
*
* Memory sharing support.
*
* Copyright (c) 2009 Citrix Systems, Inc. (Grzegorz Milos)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __MEM_SHARING_H__
#define __MEM_SHARING_H__
#include <public/domctl.h>
#include <public/memory.h>
#ifdef CONFIG_MEM_SHARING
#define mem_sharing_enabled(d) ((d)->arch.hvm.mem_sharing.enabled)
/* Auditing of memory sharing code? */
#ifndef NDEBUG
#define MEM_SHARING_AUDIT 1
#else
#define MEM_SHARING_AUDIT 0
#endif
typedef uint64_t shr_handle_t;
typedef struct rmap_hashtab {
struct list_head *bucket;
/*
* Overlaps with prev pointer of list_head in union below.
* Unlike the prev pointer, this can be NULL.
*/
void *flag;
} rmap_hashtab_t;
struct page_sharing_info
{
struct page_info *pg; /* Back pointer to the page. */
shr_handle_t handle; /* Globally unique version / handle. */
#if MEM_SHARING_AUDIT
struct list_head entry; /* List of all shared pages (entry). */
struct rcu_head rcu_head; /* List of all shared pages (entry). */
#endif
/* Reverse map of <domain,gfn> tuples for this shared frame. */
union {
struct list_head gfns;
rmap_hashtab_t hash_table;
};
};
unsigned int mem_sharing_get_nr_saved_mfns(void);
unsigned int mem_sharing_get_nr_shared_mfns(void);
/* Only fails with -ENOMEM. Enforce it with a BUG_ON wrapper. */
int __mem_sharing_unshare_page(struct domain *d,
unsigned long gfn,
bool destroy);
static inline int mem_sharing_unshare_page(struct domain *d,
unsigned long gfn)
{
int rc = __mem_sharing_unshare_page(d, gfn, false);
BUG_ON(rc && (rc != -ENOMEM));
return rc;
}
static inline bool mem_sharing_is_fork(const struct domain *d)
{
return d->parent;
}
int mem_sharing_fork_page(struct domain *d, gfn_t gfn,
bool unsharing);
/*
* If called by a foreign domain, possible errors are
* -EBUSY -> ring full
* -ENOSYS -> no ring to begin with
* and the foreign mapper is responsible for retrying.
*
* If called by the guest vcpu itself and allow_sleep is set, may
* sleep on a wait queue, so the caller is responsible for not
* holding locks on entry. It may only fail with ENOSYS
*
* If called by the guest vcpu itself and allow_sleep is not set,
* then it's the same as a foreign domain.
*/
int mem_sharing_notify_enomem(struct domain *d, unsigned long gfn,
bool allow_sleep);
int mem_sharing_memop(XEN_GUEST_HANDLE_PARAM(xen_mem_sharing_op_t) arg);
int mem_sharing_domctl(struct domain *d,
struct xen_domctl_mem_sharing_op *mec);
/*
* Scans the p2m and relinquishes any shared pages, destroying
* those for which this domain holds the final reference.
* Preemptible.
*/
int relinquish_shared_pages(struct domain *d);
#else
#define mem_sharing_enabled(d) false
static inline unsigned int mem_sharing_get_nr_saved_mfns(void)
{
return 0;
}
static inline unsigned int mem_sharing_get_nr_shared_mfns(void)
{
return 0;
}
static inline int mem_sharing_unshare_page(struct domain *d, unsigned long gfn)
{
ASSERT_UNREACHABLE();
return -EOPNOTSUPP;
}
static inline int mem_sharing_notify_enomem(struct domain *d, unsigned long gfn,
bool allow_sleep)
{
ASSERT_UNREACHABLE();
return -EOPNOTSUPP;
}
static inline bool mem_sharing_is_fork(const struct domain *d)
{
return false;
}
static inline int mem_sharing_fork_page(struct domain *d, gfn_t gfn, bool lock)
{
return -EOPNOTSUPP;
}
#endif
#endif /* __MEM_SHARING_H__ */
|
