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
   9 #include <asm/uaccess.h>
  10 #include <asm/page.h>
  11 #include <asm/pgtable.h>
  12
  13 #include <xen/interface/xen.h>
  14 #include <xen/features.h>
  15
  16 /* Xen machine address */
  17 typedef struct xmaddr {
  18         phys_addr_t maddr;
  19 } xmaddr_t;
  20
  21 /* Xen pseudo-physical address */
  22 typedef struct xpaddr {
  23         phys_addr_t paddr;
  24 } xpaddr_t;
  25
  26 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  27 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  28
  29 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  30 #define INVALID_P2M_ENTRY       (~0UL)
  31 #define FOREIGN_FRAME_BIT       (1UL<<31)
  32 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  33
  34 /* Maximum amount of memory we can handle in a domain in pages */
  35 #define MAX_DOMAIN_PAGES                                                \
  36     ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
  37
  38
  39 extern unsigned long get_phys_to_machine(unsigned long pfn);
  40 extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  41
  42 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  43 {
  44         if (xen_feature(XENFEAT_auto_translated_physmap))
  45                 return pfn;
  46
  47         return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;
  48 }
  49
  50 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  51 {
  52         if (xen_feature(XENFEAT_auto_translated_physmap))
  53                 return 1;
  54
  55         return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
  56 }
  57
  58 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  59 {
  60         unsigned long pfn;
  61
  62         if (xen_feature(XENFEAT_auto_translated_physmap))
  63                 return mfn;
  64
  65 #if 0
  66         if (unlikely((mfn >> machine_to_phys_order) != 0))
  67                 return max_mapnr;
  68 #endif
  69
  70         pfn = 0;
  71         /*
  72          * The array access can fail (e.g., device space beyond end of RAM).
  73          * In such cases it doesn't matter what we return (we return garbage),
  74          * but we must handle the fault without crashing!
  75          */
  76         __get_user(pfn, &machine_to_phys_mapping[mfn]);
  77
  78         return pfn;
  79 }
  80
  81 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
  82 {
  83         unsigned offset = phys.paddr & ~PAGE_MASK;
  84         return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
  85 }
  86
  87 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
  88 {
  89         unsigned offset = machine.maddr & ~PAGE_MASK;
  90         return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
  91 }
  92
  93 /*
  94  * We detect special mappings in one of two ways:
  95  *  1. If the MFN is an I/O page then Xen will set the m2p entry
  96  *     to be outside our maximum possible pseudophys range.
  97  *  2. If the MFN belongs to a different domain then we will certainly
  98  *     not have MFN in our p2m table. Conversely, if the page is ours,
  99  *     then we'll have p2m(m2p(MFN))==MFN.
 100  * If we detect a special mapping then it doesn't have a 'struct page'.
 101  * We force !pfn_valid() by returning an out-of-range pointer.
 102  *
 103  * NB. These checks require that, for any MFN that is not in our reservation,
 104  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 105  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 106  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 107  *
 108  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 109  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 110  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 111  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 112  */
 113 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 114 {
 115         extern unsigned long max_mapnr;
 116         unsigned long pfn = mfn_to_pfn(mfn);
 117         if ((pfn < max_mapnr)
 118             && !xen_feature(XENFEAT_auto_translated_physmap)
 119             && (get_phys_to_machine(pfn) != mfn))
 120                 return max_mapnr; /* force !pfn_valid() */
 121         /* XXX fixme; not true with sparsemem */
 122         return pfn;
 123 }
 124
 125 /* VIRT <-> MACHINE conversion */
 126 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 127 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
 128 #define virt_to_mfn(v)          (pfn_to_mfn(virt_to_pfn(v)))
 129 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 130
 131 static inline unsigned long pte_mfn(pte_t pte)
 132 {
 133         return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
 134 }
 135
 136 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 137 {
 138         pte_t pte;
 139
 140         pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
 141                         massage_pgprot(pgprot);
 142
 143         return pte;
 144 }
 145
 146 static inline pteval_t pte_val_ma(pte_t pte)
 147 {
 148         return pte.pte;
 149 }
 150
 151 static inline pte_t __pte_ma(pteval_t x)
 152 {
 153         return (pte_t) { .pte = x };
 154 }
 155
 156 #define pmd_val_ma(v) ((v).pmd)
 157 #ifdef __PAGETABLE_PUD_FOLDED
 158 #define pud_val_ma(v) ((v).pgd.pgd)
 159 #else
 160 #define pud_val_ma(v) ((v).pud)
 161 #endif
 162 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 163
 164 #define pgd_val_ma(x)   ((x).pgd)
 165
 166
 167 xmaddr_t arbitrary_virt_to_machine(void *address);
 168 unsigned long arbitrary_virt_to_mfn(void *vaddr);
 169 void make_lowmem_page_readonly(void *vaddr);
 170 void make_lowmem_page_readwrite(void *vaddr);
 171
 172 #endif /* _ASM_X86_XEN_PAGE_H */