xref: /openbmc/linux/arch/x86/include/asm/xen/page.h (revision 4949009e)
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 extern unsigned long *xen_p2m_addr;
45 extern unsigned long  xen_p2m_size;
46 extern unsigned long  xen_max_p2m_pfn;
47 
48 extern unsigned long get_phys_to_machine(unsigned long pfn);
49 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
50 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
51 extern unsigned long set_phys_range_identity(unsigned long pfn_s,
52 					     unsigned long pfn_e);
53 
54 extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
55 				   struct gnttab_map_grant_ref *kmap_ops,
56 				   struct page **pages, unsigned int count);
57 extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
58 				     struct gnttab_map_grant_ref *kmap_ops,
59 				     struct page **pages, unsigned int count);
60 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
61 
62 /*
63  * Helper functions to write or read unsigned long values to/from
64  * memory, when the access may fault.
65  */
66 static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
67 {
68 	return __put_user(val, (unsigned long __user *)addr);
69 }
70 
71 static inline int xen_safe_read_ulong(unsigned long *addr, unsigned long *val)
72 {
73 	return __get_user(*val, (unsigned long __user *)addr);
74 }
75 
76 /*
77  * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine():
78  * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. No indicator
79  *   bits (identity or foreign) are set.
80  * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set
81  *   identity or foreign indicator will be still set. __pfn_to_mfn() is
82  *   encapsulating get_phys_to_machine() which is called in special cases only.
83  * - get_phys_to_machine() is to be called by __pfn_to_mfn() only in special
84  *   cases needing an extended handling.
85  */
86 static inline unsigned long __pfn_to_mfn(unsigned long pfn)
87 {
88 	unsigned long mfn;
89 
90 	if (pfn < xen_p2m_size)
91 		mfn = xen_p2m_addr[pfn];
92 	else if (unlikely(pfn < xen_max_p2m_pfn))
93 		return get_phys_to_machine(pfn);
94 	else
95 		return IDENTITY_FRAME(pfn);
96 
97 	if (unlikely(mfn == INVALID_P2M_ENTRY))
98 		return get_phys_to_machine(pfn);
99 
100 	return mfn;
101 }
102 
103 static inline unsigned long pfn_to_mfn(unsigned long pfn)
104 {
105 	unsigned long mfn;
106 
107 	if (xen_feature(XENFEAT_auto_translated_physmap))
108 		return pfn;
109 
110 	mfn = __pfn_to_mfn(pfn);
111 
112 	if (mfn != INVALID_P2M_ENTRY)
113 		mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
114 
115 	return mfn;
116 }
117 
118 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
119 {
120 	if (xen_feature(XENFEAT_auto_translated_physmap))
121 		return 1;
122 
123 	return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY;
124 }
125 
126 static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
127 {
128 	unsigned long pfn;
129 	int ret;
130 
131 	if (xen_feature(XENFEAT_auto_translated_physmap))
132 		return mfn;
133 
134 	if (unlikely(mfn >= machine_to_phys_nr))
135 		return ~0;
136 
137 	/*
138 	 * The array access can fail (e.g., device space beyond end of RAM).
139 	 * In such cases it doesn't matter what we return (we return garbage),
140 	 * but we must handle the fault without crashing!
141 	 */
142 	ret = xen_safe_read_ulong(&machine_to_phys_mapping[mfn], &pfn);
143 	if (ret < 0)
144 		return ~0;
145 
146 	return pfn;
147 }
148 
149 static inline unsigned long mfn_to_pfn(unsigned long mfn)
150 {
151 	unsigned long pfn;
152 
153 	if (xen_feature(XENFEAT_auto_translated_physmap))
154 		return mfn;
155 
156 	pfn = mfn_to_pfn_no_overrides(mfn);
157 	if (__pfn_to_mfn(pfn) != mfn) {
158 		/*
159 		 * If this appears to be a foreign mfn (because the pfn
160 		 * doesn't map back to the mfn), then check the local override
161 		 * table to see if there's a better pfn to use.
162 		 *
163 		 * m2p_find_override_pfn returns ~0 if it doesn't find anything.
164 		 */
165 		pfn = m2p_find_override_pfn(mfn, ~0);
166 	}
167 
168 	/*
169 	 * pfn is ~0 if there are no entries in the m2p for mfn or if the
170 	 * entry doesn't map back to the mfn and m2p_override doesn't have a
171 	 * valid entry for it.
172 	 */
173 	if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
174 		pfn = mfn;
175 
176 	return pfn;
177 }
178 
179 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
180 {
181 	unsigned offset = phys.paddr & ~PAGE_MASK;
182 	return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
183 }
184 
185 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
186 {
187 	unsigned offset = machine.maddr & ~PAGE_MASK;
188 	return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
189 }
190 
191 /*
192  * We detect special mappings in one of two ways:
193  *  1. If the MFN is an I/O page then Xen will set the m2p entry
194  *     to be outside our maximum possible pseudophys range.
195  *  2. If the MFN belongs to a different domain then we will certainly
196  *     not have MFN in our p2m table. Conversely, if the page is ours,
197  *     then we'll have p2m(m2p(MFN))==MFN.
198  * If we detect a special mapping then it doesn't have a 'struct page'.
199  * We force !pfn_valid() by returning an out-of-range pointer.
200  *
201  * NB. These checks require that, for any MFN that is not in our reservation,
202  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
203  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
204  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
205  *
206  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
207  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
208  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
209  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
210  */
211 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
212 {
213 	unsigned long pfn;
214 
215 	if (xen_feature(XENFEAT_auto_translated_physmap))
216 		return mfn;
217 
218 	pfn = mfn_to_pfn(mfn);
219 	if (__pfn_to_mfn(pfn) != mfn)
220 		return -1; /* force !pfn_valid() */
221 	return pfn;
222 }
223 
224 /* VIRT <-> MACHINE conversion */
225 #define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))
226 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
227 #define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
228 #define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
229 
230 static inline unsigned long pte_mfn(pte_t pte)
231 {
232 	return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
233 }
234 
235 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
236 {
237 	pte_t pte;
238 
239 	pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
240 			massage_pgprot(pgprot);
241 
242 	return pte;
243 }
244 
245 static inline pteval_t pte_val_ma(pte_t pte)
246 {
247 	return pte.pte;
248 }
249 
250 static inline pte_t __pte_ma(pteval_t x)
251 {
252 	return (pte_t) { .pte = x };
253 }
254 
255 #define pmd_val_ma(v) ((v).pmd)
256 #ifdef __PAGETABLE_PUD_FOLDED
257 #define pud_val_ma(v) ((v).pgd.pgd)
258 #else
259 #define pud_val_ma(v) ((v).pud)
260 #endif
261 #define __pmd_ma(x)	((pmd_t) { (x) } )
262 
263 #define pgd_val_ma(x)	((x).pgd)
264 
265 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid);
266 
267 xmaddr_t arbitrary_virt_to_machine(void *address);
268 unsigned long arbitrary_virt_to_mfn(void *vaddr);
269 void make_lowmem_page_readonly(void *vaddr);
270 void make_lowmem_page_readwrite(void *vaddr);
271 
272 #define xen_remap(cookie, size) ioremap((cookie), (size));
273 #define xen_unmap(cookie) iounmap((cookie))
274 
275 static inline bool xen_arch_need_swiotlb(struct device *dev,
276 					 unsigned long pfn,
277 					 unsigned long mfn)
278 {
279 	return false;
280 }
281 
282 #endif /* _ASM_X86_XEN_PAGE_H */
283