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