Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
page.h
Go to the documentation of this file.
1 #ifndef _ASM_X86_XEN_PAGE_H
2 #define _ASM_X86_XEN_PAGE_H
3 
4 #include <linux/kernel.h>
5 #include <linux/types.h>
6 #include <linux/spinlock.h>
7 #include <linux/pfn.h>
8 #include <linux/mm.h>
9 
10 #include <asm/uaccess.h>
11 #include <asm/page.h>
12 #include <asm/pgtable.h>
13 
14 #include <xen/interface/xen.h>
15 #include <xen/grant_table.h>
16 #include <xen/features.h>
17 
18 /* Xen machine address */
19 typedef struct xmaddr {
21 } xmaddr_t;
22 
23 /* Xen pseudo-physical address */
24 typedef struct xpaddr {
26 } xpaddr_t;
27 
28 #define XMADDR(x) ((xmaddr_t) { .maddr = (x) })
29 #define XPADDR(x) ((xpaddr_t) { .paddr = (x) })
30 
31 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
32 #define INVALID_P2M_ENTRY (~0UL)
33 #define FOREIGN_FRAME_BIT (1UL<<(BITS_PER_LONG-1))
34 #define IDENTITY_FRAME_BIT (1UL<<(BITS_PER_LONG-2))
35 #define FOREIGN_FRAME(m) ((m) | FOREIGN_FRAME_BIT)
36 #define IDENTITY_FRAME(m) ((m) | IDENTITY_FRAME_BIT)
37 
38 /* Maximum amount of memory we can handle in a domain in pages */
39 #define MAX_DOMAIN_PAGES \
40  ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
41 
42 extern unsigned long *machine_to_phys_mapping;
43 extern unsigned long machine_to_phys_nr;
44 
45 extern unsigned long get_phys_to_machine(unsigned long pfn);
46 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
47 extern bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn);
48 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
49 extern unsigned long set_phys_range_identity(unsigned long pfn_s,
50  unsigned long pfn_e);
51 
52 extern int m2p_add_override(unsigned long mfn, struct page *page,
53  struct gnttab_map_grant_ref *kmap_op);
54 extern int m2p_remove_override(struct page *page,
55  struct gnttab_map_grant_ref *kmap_op);
56 extern struct page *m2p_find_override(unsigned long mfn);
57 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
58 
59 static inline unsigned long pfn_to_mfn(unsigned long pfn)
60 {
61  unsigned long mfn;
62 
63  if (xen_feature(XENFEAT_auto_translated_physmap))
64  return pfn;
65 
66  mfn = get_phys_to_machine(pfn);
67 
68  if (mfn != INVALID_P2M_ENTRY)
70 
71  return mfn;
72 }
73 
74 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
75 {
76  if (xen_feature(XENFEAT_auto_translated_physmap))
77  return 1;
78 
80 }
81 
82 static inline unsigned long mfn_to_pfn(unsigned long mfn)
83 {
84  unsigned long pfn;
85  int ret = 0;
86 
87  if (xen_feature(XENFEAT_auto_translated_physmap))
88  return mfn;
89 
90  if (unlikely(mfn >= machine_to_phys_nr)) {
91  pfn = ~0;
92  goto try_override;
93  }
94  pfn = 0;
95  /*
96  * The array access can fail (e.g., device space beyond end of RAM).
97  * In such cases it doesn't matter what we return (we return garbage),
98  * but we must handle the fault without crashing!
99  */
100  ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
101 try_override:
102  /* ret might be < 0 if there are no entries in the m2p for mfn */
103  if (ret < 0)
104  pfn = ~0;
105  else if (get_phys_to_machine(pfn) != mfn)
106  /*
107  * If this appears to be a foreign mfn (because the pfn
108  * doesn't map back to the mfn), then check the local override
109  * table to see if there's a better pfn to use.
110  *
111  * m2p_find_override_pfn returns ~0 if it doesn't find anything.
112  */
113  pfn = m2p_find_override_pfn(mfn, ~0);
114 
115  /*
116  * pfn is ~0 if there are no entries in the m2p for mfn or if the
117  * entry doesn't map back to the mfn and m2p_override doesn't have a
118  * valid entry for it.
119  */
120  if (pfn == ~0 &&
121  get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))
122  pfn = mfn;
123 
124  return pfn;
125 }
126 
127 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
128 {
129  unsigned offset = phys.paddr & ~PAGE_MASK;
130  return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
131 }
132 
133 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
134 {
135  unsigned offset = machine.maddr & ~PAGE_MASK;
136  return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
137 }
138 
139 /*
140  * We detect special mappings in one of two ways:
141  * 1. If the MFN is an I/O page then Xen will set the m2p entry
142  * to be outside our maximum possible pseudophys range.
143  * 2. If the MFN belongs to a different domain then we will certainly
144  * not have MFN in our p2m table. Conversely, if the page is ours,
145  * then we'll have p2m(m2p(MFN))==MFN.
146  * If we detect a special mapping then it doesn't have a 'struct page'.
147  * We force !pfn_valid() by returning an out-of-range pointer.
148  *
149  * NB. These checks require that, for any MFN that is not in our reservation,
150  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
151  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
152  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
153  *
154  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
155  * use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
156  * require. In all the cases we care about, the FOREIGN_FRAME bit is
157  * masked (e.g., pfn_to_mfn()) so behaviour there is correct.
158  */
159 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
160 {
161  unsigned long pfn = mfn_to_pfn(mfn);
162  if (get_phys_to_machine(pfn) != mfn)
163  return -1; /* force !pfn_valid() */
164  return pfn;
165 }
166 
167 /* VIRT <-> MACHINE conversion */
168 #define virt_to_machine(v) (phys_to_machine(XPADDR(__pa(v))))
169 #define virt_to_pfn(v) (PFN_DOWN(__pa(v)))
170 #define virt_to_mfn(v) (pfn_to_mfn(virt_to_pfn(v)))
171 #define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT))
172 
173 static inline unsigned long pte_mfn(pte_t pte)
174 {
175  return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
176 }
177 
178 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
179 {
180  pte_t pte;
181 
182  pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
183  massage_pgprot(pgprot);
184 
185  return pte;
186 }
187 
188 static inline pteval_t pte_val_ma(pte_t pte)
189 {
190  return pte.pte;
191 }
192 
193 static inline pte_t __pte_ma(pteval_t x)
194 {
195  return (pte_t) { .pte = x };
196 }
197 
198 #define pmd_val_ma(v) ((v).pmd)
199 #ifdef __PAGETABLE_PUD_FOLDED
200 #define pud_val_ma(v) ((v).pgd.pgd)
201 #else
202 #define pud_val_ma(v) ((v).pud)
203 #endif
204 #define __pmd_ma(x) ((pmd_t) { (x) } )
205 
206 #define pgd_val_ma(x) ((x).pgd)
207 
208 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid);
209 
211 unsigned long arbitrary_virt_to_mfn(void *vaddr);
212 void make_lowmem_page_readonly(void *vaddr);
214 
215 #endif /* _ASM_X86_XEN_PAGE_H */