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/features.h>
  16
  17 /* Xen machine address */
  18 typedef struct xmaddr {
  19         phys_addr_t maddr;
  20 } xmaddr_t;
  21
  22 /* Xen pseudo-physical address */
  23 typedef struct xpaddr {
  24         phys_addr_t paddr;
  25 } xpaddr_t;
  26
  27 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  28 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  29
  30 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  31 #define INVALID_P2M_ENTRY       (~0UL)
  32 #define FOREIGN_FRAME_BIT       (1UL<<(BITS_PER_LONG-1))
  33 #define IDENTITY_FRAME_BIT      (1UL<<(BITS_PER_LONG-2))
  34 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  35 #define IDENTITY_FRAME(m)       ((m) | IDENTITY_FRAME_BIT)
  36
  37 /* Maximum amount of memory we can handle in a domain in pages */
  38 #define MAX_DOMAIN_PAGES                                                \
  39     ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
  40
  41 extern unsigned long *machine_to_phys_mapping;
  42 extern unsigned int   machine_to_phys_order;
  43
  44 extern unsigned long get_phys_to_machine(unsigned long pfn);
  45 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  46 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
  47 extern unsigned long set_phys_range_identity(unsigned long pfn_s,
  48                                              unsigned long pfn_e);
  49
  50 extern int m2p_add_override(unsigned long mfn, struct page *page,
  51                             bool clear_pte);
  52 extern int m2p_remove_override(struct page *page, bool clear_pte);
  53 extern struct page *m2p_find_override(unsigned long mfn);
  54 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
  55
  56 #ifdef CONFIG_XEN_DEBUG_FS
  57 extern int p2m_dump_show(struct seq_file *m, void *v);
  58 #endif
  59 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  60 {
  61         unsigned long mfn;
  62
  63         if (xen_feature(XENFEAT_auto_translated_physmap))
  64                 return pfn;
  65
  66         mfn = get_phys_to_machine(pfn);
  67
  68         if (mfn != INVALID_P2M_ENTRY)
  69                 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
  70
  71         return mfn;
  72 }
  73
  74 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  75 {
  76         if (xen_feature(XENFEAT_auto_translated_physmap))
  77                 return 1;
  78
  79         return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
  80 }
  81
  82 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  83 {
  84         unsigned long pfn;
  85         int ret = 0;
  86
  87         if (xen_feature(XENFEAT_auto_translated_physmap))
  88                 return mfn;
  89
  90         if (unlikely((mfn >> machine_to_phys_order) != 0)) {
  91                 pfn = ~0;
  92                 goto try_override;
  93         }
  94         pfn = 0;
  95         /*
  96          * The array access can fail (e.g., device space beyond end of RAM).
  97          * In such cases it doesn't matter what we return (we return garbage),
  98          * but we must handle the fault without crashing!
  99          */
 100         ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
 101 try_override:
 102         /* ret might be < 0 if there are no entries in the m2p for mfn */
 103         if (ret < 0)
 104                 pfn = ~0;
 105         else if (get_phys_to_machine(pfn) != mfn)
 106                 /*
 107                  * If this appears to be a foreign mfn (because the pfn
 108                  * doesn't map back to the mfn), then check the local override
 109                  * table to see if there's a better pfn to use.
 110                  *
 111                  * m2p_find_override_pfn returns ~0 if it doesn't find anything.
 112                  */
 113                 pfn = m2p_find_override_pfn(mfn, ~0);
 114
 115         /*
 116          * pfn is ~0 if there are no entries in the m2p for mfn or if the
 117          * entry doesn't map back to the mfn and m2p_override doesn't have a
 118          * valid entry for it.
 119          */
 120         if (pfn == ~0 &&
 121                         get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))
 122                 pfn = mfn;
 123
 124         return pfn;
 125 }
 126
 127 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
 128 {
 129         unsigned offset = phys.paddr & ~PAGE_MASK;
 130         return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
 131 }
 132
 133 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
 134 {
 135         unsigned offset = machine.maddr & ~PAGE_MASK;
 136         return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
 137 }
 138
 139 /*
 140  * We detect special mappings in one of two ways:
 141  *  1. If the MFN is an I/O page then Xen will set the m2p entry
 142  *     to be outside our maximum possible pseudophys range.
 143  *  2. If the MFN belongs to a different domain then we will certainly
 144  *     not have MFN in our p2m table. Conversely, if the page is ours,
 145  *     then we'll have p2m(m2p(MFN))==MFN.
 146  * If we detect a special mapping then it doesn't have a 'struct page'.
 147  * We force !pfn_valid() by returning an out-of-range pointer.
 148  *
 149  * NB. These checks require that, for any MFN that is not in our reservation,
 150  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 151  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 152  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 153  *
 154  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 155  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 156  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 157  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 158  */
 159 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 160 {
 161         unsigned long pfn = mfn_to_pfn(mfn);
 162         if (get_phys_to_machine(pfn) != mfn)
 163                 return -1; /* force !pfn_valid() */
 164         return pfn;
 165 }
 166
 167 /* VIRT <-> MACHINE conversion */
 168 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 169 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
 170 #define virt_to_mfn(v)          (pfn_to_mfn(virt_to_pfn(v)))
 171 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 172
 173 static inline unsigned long pte_mfn(pte_t pte)
 174 {
 175         return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
 176 }
 177
 178 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 179 {
 180         pte_t pte;
 181
 182         pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
 183                         massage_pgprot(pgprot);
 184
 185         return pte;
 186 }
 187
 188 static inline pteval_t pte_val_ma(pte_t pte)
 189 {
 190         return pte.pte;
 191 }
 192
 193 static inline pte_t __pte_ma(pteval_t x)
 194 {
 195         return (pte_t) { .pte = x };
 196 }
 197
 198 #define pmd_val_ma(v) ((v).pmd)
 199 #ifdef __PAGETABLE_PUD_FOLDED
 200 #define pud_val_ma(v) ((v).pgd.pgd)
 201 #else
 202 #define pud_val_ma(v) ((v).pud)
 203 #endif
 204 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 205
 206 #define pgd_val_ma(x)   ((x).pgd)
 207
 208 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid);
 209
 210 xmaddr_t arbitrary_virt_to_machine(void *address);
 211 unsigned long arbitrary_virt_to_mfn(void *vaddr);
 212 void make_lowmem_page_readonly(void *vaddr);
 213 void make_lowmem_page_readwrite(void *vaddr);
 214
 215 #endif /* _ASM_X86_XEN_PAGE_H */