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

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