arch/x86/include/asm/xen/page.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_XEN_PAGE_H
   3 #define _ASM_X86_XEN_PAGE_H
   4
   5 #include <linux/kernel.h>
   6 #include <linux/types.h>
   7 #include <linux/spinlock.h>
   8 #include <linux/pfn.h>
   9 #include <linux/mm.h>
  10 #include <linux/device.h>
  11
  12 #include <linux/uaccess.h>
  13 #include <asm/page.h>
  14 #include <asm/pgtable.h>
  15
  16 #include <xen/interface/xen.h>
  17 #include <xen/interface/grant_table.h>
  18 #include <xen/features.h>
  19
  20 /* Xen machine address */
  21 typedef struct xmaddr {
  22         phys_addr_t maddr;
  23 } xmaddr_t;
  24
  25 /* Xen pseudo-physical address */
  26 typedef struct xpaddr {
  27         phys_addr_t paddr;
  28 } xpaddr_t;
  29
  30 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  31 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  32
  33 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  34 #define INVALID_P2M_ENTRY       (~0UL)
  35 #define FOREIGN_FRAME_BIT       (1UL<<(BITS_PER_LONG-1))
  36 #define IDENTITY_FRAME_BIT      (1UL<<(BITS_PER_LONG-2))
  37 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  38 #define IDENTITY_FRAME(m)       ((m) | IDENTITY_FRAME_BIT)
  39
  40 #define P2M_PER_PAGE            (PAGE_SIZE / sizeof(unsigned long))
  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 int xen_alloc_p2m_entry(unsigned long pfn);
  49
  50 extern unsigned long get_phys_to_machine(unsigned long pfn);
  51 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  52 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  53 extern unsigned long __init set_phys_range_identity(unsigned long pfn_s,
  54                                                     unsigned long pfn_e);
  55
  56 #ifdef CONFIG_XEN_PV
  57 extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
  58                                    struct gnttab_map_grant_ref *kmap_ops,
  59                                    struct page **pages, unsigned int count);
  60 extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
  61                                      struct gnttab_unmap_grant_ref *kunmap_ops,
  62                                      struct page **pages, unsigned int count);
  63 #else
  64 static inline int
  65 set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
  66                         struct gnttab_map_grant_ref *kmap_ops,
  67                         struct page **pages, unsigned int count)
  68 {
  69         return 0;
  70 }
  71
  72 static inline int
  73 clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
  74                           struct gnttab_unmap_grant_ref *kunmap_ops,
  75                           struct page **pages, unsigned int count)
  76 {
  77         return 0;
  78 }
  79 #endif
  80
  81 /*
  82  * Helper functions to write or read unsigned long values to/from
  83  * memory, when the access may fault.
  84  */
  85 static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
  86 {
  87         return __put_user(val, (unsigned long __user *)addr);
  88 }
  89
  90 static inline int xen_safe_read_ulong(unsigned long *addr, unsigned long *val)
  91 {
  92         return __get_user(*val, (unsigned long __user *)addr);
  93 }
  94
  95 #ifdef CONFIG_XEN_PV
  96 /*
  97  * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine():
  98  * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. No indicator
  99  *   bits (identity or foreign) are set.
 100  * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set
 101  *   identity or foreign indicator will be still set. __pfn_to_mfn() is
 102  *   encapsulating get_phys_to_machine() which is called in special cases only.
 103  * - get_phys_to_machine() is to be called by __pfn_to_mfn() only in special
 104  *   cases needing an extended handling.
 105  */
 106 static inline unsigned long __pfn_to_mfn(unsigned long pfn)
 107 {
 108         unsigned long mfn;
 109
 110         if (pfn < xen_p2m_size)
 111                 mfn = xen_p2m_addr[pfn];
 112         else if (unlikely(pfn < xen_max_p2m_pfn))
 113                 return get_phys_to_machine(pfn);
 114         else
 115                 return IDENTITY_FRAME(pfn);
 116
 117         if (unlikely(mfn == INVALID_P2M_ENTRY))
 118                 return get_phys_to_machine(pfn);
 119
 120         return mfn;
 121 }
 122 #else
 123 static inline unsigned long __pfn_to_mfn(unsigned long pfn)
 124 {
 125         return pfn;
 126 }
 127 #endif
 128
 129 static inline unsigned long pfn_to_mfn(unsigned long pfn)
 130 {
 131         unsigned long mfn;
 132
 133         /*
 134          * Some x86 code are still using pfn_to_mfn instead of
 135          * pfn_to_mfn. This will have to be removed when we figured
 136          * out which call.
 137          */
 138         if (xen_feature(XENFEAT_auto_translated_physmap))
 139                 return pfn;
 140
 141         mfn = __pfn_to_mfn(pfn);
 142
 143         if (mfn != INVALID_P2M_ENTRY)
 144                 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
 145
 146         return mfn;
 147 }
 148
 149 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
 150 {
 151         if (xen_feature(XENFEAT_auto_translated_physmap))
 152                 return 1;
 153
 154         return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY;
 155 }
 156
 157 static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
 158 {
 159         unsigned long pfn;
 160         int ret;
 161
 162         if (unlikely(mfn >= machine_to_phys_nr))
 163                 return ~0;
 164
 165         /*
 166          * The array access can fail (e.g., device space beyond end of RAM).
 167          * In such cases it doesn't matter what we return (we return garbage),
 168          * but we must handle the fault without crashing!
 169          */
 170         ret = xen_safe_read_ulong(&machine_to_phys_mapping[mfn], &pfn);
 171         if (ret < 0)
 172                 return ~0;
 173
 174         return pfn;
 175 }
 176
 177 static inline unsigned long mfn_to_pfn(unsigned long mfn)
 178 {
 179         unsigned long pfn;
 180
 181         /*
 182          * Some x86 code are still using mfn_to_pfn instead of
 183          * gfn_to_pfn. This will have to be removed when we figure
 184          * out which call.
 185          */
 186         if (xen_feature(XENFEAT_auto_translated_physmap))
 187                 return mfn;
 188
 189         pfn = mfn_to_pfn_no_overrides(mfn);
 190         if (__pfn_to_mfn(pfn) != mfn)
 191                 pfn = ~0;
 192
 193         /*
 194          * pfn is ~0 if there are no entries in the m2p for mfn or the
 195          * entry doesn't map back to the mfn.
 196          */
 197         if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
 198                 pfn = mfn;
 199
 200         return pfn;
 201 }
 202
 203 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
 204 {
 205         unsigned offset = phys.paddr & ~PAGE_MASK;
 206         return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
 207 }
 208
 209 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
 210 {
 211         unsigned offset = machine.maddr & ~PAGE_MASK;
 212         return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
 213 }
 214
 215 /* Pseudo-physical <-> Guest conversion */
 216 static inline unsigned long pfn_to_gfn(unsigned long pfn)
 217 {
 218         if (xen_feature(XENFEAT_auto_translated_physmap))
 219                 return pfn;
 220         else
 221                 return pfn_to_mfn(pfn);
 222 }
 223
 224 static inline unsigned long gfn_to_pfn(unsigned long gfn)
 225 {
 226         if (xen_feature(XENFEAT_auto_translated_physmap))
 227                 return gfn;
 228         else
 229                 return mfn_to_pfn(gfn);
 230 }
 231
 232 /* Pseudo-physical <-> Bus conversion */
 233 #define pfn_to_bfn(pfn)         pfn_to_gfn(pfn)
 234 #define bfn_to_pfn(bfn)         gfn_to_pfn(bfn)
 235
 236 /*
 237  * We detect special mappings in one of two ways:
 238  *  1. If the MFN is an I/O page then Xen will set the m2p entry
 239  *     to be outside our maximum possible pseudophys range.
 240  *  2. If the MFN belongs to a different domain then we will certainly
 241  *     not have MFN in our p2m table. Conversely, if the page is ours,
 242  *     then we'll have p2m(m2p(MFN))==MFN.
 243  * If we detect a special mapping then it doesn't have a 'struct page'.
 244  * We force !pfn_valid() by returning an out-of-range pointer.
 245  *
 246  * NB. These checks require that, for any MFN that is not in our reservation,
 247  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 248  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 249  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 250  *
 251  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 252  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 253  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 254  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 255  */
 256 static inline unsigned long bfn_to_local_pfn(unsigned long mfn)
 257 {
 258         unsigned long pfn;
 259
 260         if (xen_feature(XENFEAT_auto_translated_physmap))
 261                 return mfn;
 262
 263         pfn = mfn_to_pfn(mfn);
 264         if (__pfn_to_mfn(pfn) != mfn)
 265                 return -1; /* force !pfn_valid() */
 266         return pfn;
 267 }
 268
 269 /* VIRT <-> MACHINE conversion */
 270 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 271 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
 272 #define virt_to_mfn(v)          (pfn_to_mfn(virt_to_pfn(v)))
 273 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 274
 275 /* VIRT <-> GUEST conversion */
 276 #define virt_to_gfn(v)          (pfn_to_gfn(virt_to_pfn(v)))
 277 #define gfn_to_virt(g)          (__va(gfn_to_pfn(g) << PAGE_SHIFT))
 278
 279 static inline unsigned long pte_mfn(pte_t pte)
 280 {
 281         return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
 282 }
 283
 284 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 285 {
 286         pte_t pte;
 287
 288         pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
 289                         massage_pgprot(pgprot);
 290
 291         return pte;
 292 }
 293
 294 static inline pteval_t pte_val_ma(pte_t pte)
 295 {
 296         return pte.pte;
 297 }
 298
 299 static inline pte_t __pte_ma(pteval_t x)
 300 {
 301         return (pte_t) { .pte = x };
 302 }
 303
 304 #define pmd_val_ma(v) ((v).pmd)
 305 #ifdef __PAGETABLE_PUD_FOLDED
 306 #define pud_val_ma(v) ((v).p4d.pgd.pgd)
 307 #else
 308 #define pud_val_ma(v) ((v).pud)
 309 #endif
 310 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 311
 312 #ifdef __PAGETABLE_P4D_FOLDED
 313 #define p4d_val_ma(x)   ((x).pgd.pgd)
 314 #else
 315 #define p4d_val_ma(x)   ((x).p4d)
 316 #endif
 317
 318 xmaddr_t arbitrary_virt_to_machine(void *address);
 319 unsigned long arbitrary_virt_to_mfn(void *vaddr);
 320 void make_lowmem_page_readonly(void *vaddr);
 321 void make_lowmem_page_readwrite(void *vaddr);
 322
 323 #define xen_remap(cookie, size) ioremap((cookie), (size));
 324 #define xen_unmap(cookie) iounmap((cookie))
 325
 326 static inline bool xen_arch_need_swiotlb(struct device *dev,
 327                                          phys_addr_t phys,
 328                                          dma_addr_t dev_addr)
 329 {
 330         return false;
 331 }
 332
 333 static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
 334 {
 335         return __get_free_pages(__GFP_NOWARN, order);
 336 }
 337
 338 #endif /* _ASM_X86_XEN_PAGE_H */