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 {
20 phys_addr_t maddr;
21 } xmaddr_t;
22
23 /* Xen pseudo-physical address */
24 typedef struct xpaddr {
25 phys_addr_t paddr;
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 __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
48 extern unsigned long set_phys_range_identity(unsigned long pfn_s,
49 unsigned long pfn_e);
50
51 extern int m2p_add_override(unsigned long mfn, struct page *page,
52 struct gnttab_map_grant_ref *kmap_op);
53 extern int m2p_remove_override(struct page *page,
54 struct gnttab_map_grant_ref *kmap_op);
55 extern struct page *m2p_find_override(unsigned long mfn);
56 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
57
pfn_to_mfn(unsigned long pfn)58 static inline unsigned long pfn_to_mfn(unsigned long pfn)
59 {
60 unsigned long mfn;
61
62 if (xen_feature(XENFEAT_auto_translated_physmap))
63 return pfn;
64
65 mfn = get_phys_to_machine(pfn);
66
67 if (mfn != INVALID_P2M_ENTRY)
68 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
69
70 return mfn;
71 }
72
phys_to_machine_mapping_valid(unsigned long pfn)73 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
74 {
75 if (xen_feature(XENFEAT_auto_translated_physmap))
76 return 1;
77
78 return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
79 }
80
mfn_to_pfn(unsigned long mfn)81 static inline unsigned long mfn_to_pfn(unsigned long mfn)
82 {
83 unsigned long pfn;
84 int ret = 0;
85
86 if (xen_feature(XENFEAT_auto_translated_physmap))
87 return mfn;
88
89 if (unlikely(mfn >= machine_to_phys_nr)) {
90 pfn = ~0;
91 goto try_override;
92 }
93 pfn = 0;
94 /*
95 * The array access can fail (e.g., device space beyond end of RAM).
96 * In such cases it doesn't matter what we return (we return garbage),
97 * but we must handle the fault without crashing!
98 */
99 ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
100 try_override:
101 /* ret might be < 0 if there are no entries in the m2p for mfn */
102 if (ret < 0)
103 pfn = ~0;
104 else if (get_phys_to_machine(pfn) != mfn)
105 /*
106 * If this appears to be a foreign mfn (because the pfn
107 * doesn't map back to the mfn), then check the local override
108 * table to see if there's a better pfn to use.
109 *
110 * m2p_find_override_pfn returns ~0 if it doesn't find anything.
111 */
112 pfn = m2p_find_override_pfn(mfn, ~0);
113
114 /*
115 * pfn is ~0 if there are no entries in the m2p for mfn or if the
116 * entry doesn't map back to the mfn and m2p_override doesn't have a
117 * valid entry for it.
118 */
119 if (pfn == ~0 &&
120 get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))
121 pfn = mfn;
122
123 return pfn;
124 }
125
phys_to_machine(xpaddr_t phys)126 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
127 {
128 unsigned offset = phys.paddr & ~PAGE_MASK;
129 return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
130 }
131
machine_to_phys(xmaddr_t machine)132 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
133 {
134 unsigned offset = machine.maddr & ~PAGE_MASK;
135 return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
136 }
137
138 /*
139 * We detect special mappings in one of two ways:
140 * 1. If the MFN is an I/O page then Xen will set the m2p entry
141 * to be outside our maximum possible pseudophys range.
142 * 2. If the MFN belongs to a different domain then we will certainly
143 * not have MFN in our p2m table. Conversely, if the page is ours,
144 * then we'll have p2m(m2p(MFN))==MFN.
145 * If we detect a special mapping then it doesn't have a 'struct page'.
146 * We force !pfn_valid() by returning an out-of-range pointer.
147 *
148 * NB. These checks require that, for any MFN that is not in our reservation,
149 * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
150 * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
151 * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
152 *
153 * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
154 * use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
155 * require. In all the cases we care about, the FOREIGN_FRAME bit is
156 * masked (e.g., pfn_to_mfn()) so behaviour there is correct.
157 */
mfn_to_local_pfn(unsigned long mfn)158 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
159 {
160 unsigned long pfn = mfn_to_pfn(mfn);
161 if (get_phys_to_machine(pfn) != mfn)
162 return -1; /* force !pfn_valid() */
163 return pfn;
164 }
165
166 /* VIRT <-> MACHINE conversion */
167 #define virt_to_machine(v) (phys_to_machine(XPADDR(__pa(v))))
168 #define virt_to_pfn(v) (PFN_DOWN(__pa(v)))
169 #define virt_to_mfn(v) (pfn_to_mfn(virt_to_pfn(v)))
170 #define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT))
171
pte_mfn(pte_t pte)172 static inline unsigned long pte_mfn(pte_t pte)
173 {
174 return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
175 }
176
mfn_pte(unsigned long page_nr,pgprot_t pgprot)177 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
178 {
179 pte_t pte;
180
181 pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
182 massage_pgprot(pgprot);
183
184 return pte;
185 }
186
pte_val_ma(pte_t pte)187 static inline pteval_t pte_val_ma(pte_t pte)
188 {
189 return pte.pte;
190 }
191
__pte_ma(pteval_t x)192 static inline pte_t __pte_ma(pteval_t x)
193 {
194 return (pte_t) { .pte = x };
195 }
196
197 #define pmd_val_ma(v) ((v).pmd)
198 #ifdef __PAGETABLE_PUD_FOLDED
199 #define pud_val_ma(v) ((v).pgd.pgd)
200 #else
201 #define pud_val_ma(v) ((v).pud)
202 #endif
203 #define __pmd_ma(x) ((pmd_t) { (x) } )
204
205 #define pgd_val_ma(x) ((x).pgd)
206
207 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid);
208
209 xmaddr_t arbitrary_virt_to_machine(void *address);
210 unsigned long arbitrary_virt_to_mfn(void *vaddr);
211 void make_lowmem_page_readonly(void *vaddr);
212 void make_lowmem_page_readwrite(void *vaddr);
213
214 #endif /* _ASM_X86_XEN_PAGE_H */
215