include/asm-x86/xen/page.h

   1 #ifndef ASM_X86__XEN__PAGE_H
   2 #define ASM_X86__XEN__PAGE_H
   3
   4 #include <linux/pfn.h>
   5
   6 #include <asm/uaccess.h>
   7 #include <asm/pgtable.h>
   8
   9 #include <xen/features.h>
  10
  11 /* Xen machine address */
  12 typedef struct xmaddr {
  13         phys_addr_t maddr;
  14 } xmaddr_t;
  15
  16 /* Xen pseudo-physical address */
  17 typedef struct xpaddr {
  18         phys_addr_t paddr;
  19 } xpaddr_t;
  20
  21 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  22 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  23
  24 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  25 #define INVALID_P2M_ENTRY       (~0UL)
  26 #define FOREIGN_FRAME_BIT       (1UL<<31)
  27 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  28
  29 /* Maximum amount of memory we can handle in a domain in pages */
  30 #define MAX_DOMAIN_PAGES                                                \
  31     ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
  32
  33
  34 extern unsigned long get_phys_to_machine(unsigned long pfn);
  35 extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  36
  37 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  38 {
  39         if (xen_feature(XENFEAT_auto_translated_physmap))
  40                 return pfn;
  41
  42         return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;
  43 }
  44
  45 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  46 {
  47         if (xen_feature(XENFEAT_auto_translated_physmap))
  48                 return 1;
  49
  50         return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
  51 }
  52
  53 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  54 {
  55         unsigned long pfn;
  56
  57         if (xen_feature(XENFEAT_auto_translated_physmap))
  58                 return mfn;
  59
  60 #if 0
  61         if (unlikely((mfn >> machine_to_phys_order) != 0))
  62                 return max_mapnr;
  63 #endif
  64
  65         pfn = 0;
  66         /*
  67          * The array access can fail (e.g., device space beyond end of RAM).
  68          * In such cases it doesn't matter what we return (we return garbage),
  69          * but we must handle the fault without crashing!
  70          */
  71         __get_user(pfn, &machine_to_phys_mapping[mfn]);
  72
  73         return pfn;
  74 }
  75
  76 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
  77 {
  78         unsigned offset = phys.paddr & ~PAGE_MASK;
  79         return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
  80 }
  81
  82 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
  83 {
  84         unsigned offset = machine.maddr & ~PAGE_MASK;
  85         return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
  86 }
  87
  88 /*
  89  * We detect special mappings in one of two ways:
  90  *  1. If the MFN is an I/O page then Xen will set the m2p entry
  91  *     to be outside our maximum possible pseudophys range.
  92  *  2. If the MFN belongs to a different domain then we will certainly
  93  *     not have MFN in our p2m table. Conversely, if the page is ours,
  94  *     then we'll have p2m(m2p(MFN))==MFN.
  95  * If we detect a special mapping then it doesn't have a 'struct page'.
  96  * We force !pfn_valid() by returning an out-of-range pointer.
  97  *
  98  * NB. These checks require that, for any MFN that is not in our reservation,
  99  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 100  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 101  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 102  *
 103  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 104  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 105  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 106  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 107  */
 108 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 109 {
 110         extern unsigned long max_mapnr;
 111         unsigned long pfn = mfn_to_pfn(mfn);
 112         if ((pfn < max_mapnr)
 113             && !xen_feature(XENFEAT_auto_translated_physmap)
 114             && (get_phys_to_machine(pfn) != mfn))
 115                 return max_mapnr; /* force !pfn_valid() */
 116         /* XXX fixme; not true with sparsemem */
 117         return pfn;
 118 }
 119
 120 /* VIRT <-> MACHINE conversion */
 121 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 122 #define virt_to_mfn(v)          (pfn_to_mfn(PFN_DOWN(__pa(v))))
 123 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 124
 125 static inline unsigned long pte_mfn(pte_t pte)
 126 {
 127         return (pte.pte & PTE_MASK) >> PAGE_SHIFT;
 128 }
 129
 130 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 131 {
 132         pte_t pte;
 133
 134         pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
 135                 (pgprot_val(pgprot) & __supported_pte_mask);
 136
 137         return pte;
 138 }
 139
 140 static inline pteval_t pte_val_ma(pte_t pte)
 141 {
 142         return pte.pte;
 143 }
 144
 145 static inline pte_t __pte_ma(pteval_t x)
 146 {
 147         return (pte_t) { .pte = x };
 148 }
 149
 150 #define pmd_val_ma(v) ((v).pmd)
 151 #ifdef __PAGETABLE_PUD_FOLDED
 152 #define pud_val_ma(v) ((v).pgd.pgd)
 153 #else
 154 #define pud_val_ma(v) ((v).pud)
 155 #endif
 156 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 157
 158 #define pgd_val_ma(x)   ((x).pgd)
 159
 160
 161 xmaddr_t arbitrary_virt_to_machine(void *address);
 162 void make_lowmem_page_readonly(void *vaddr);
 163 void make_lowmem_page_readwrite(void *vaddr);
 164
 165 #endif /* ASM_X86__XEN__PAGE_H */