page-3level.h

xen 3.2.2 源码

#ifndef __X86_32_PAGE_3LEVEL_H__
#define __X86_32_PAGE_3LEVEL_H__

#define L1_PAGETABLE_SHIFT      12
#define L2_PAGETABLE_SHIFT      21
#define L3_PAGETABLE_SHIFT      30
#define PAGE_SHIFT              L1_PAGETABLE_SHIFT
#define ROOT_PAGETABLE_SHIFT    L3_PAGETABLE_SHIFT

#define PAGETABLE_ORDER         9
#define L1_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
#define L2_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
#define L3_PAGETABLE_ENTRIES    4
#define ROOT_PAGETABLE_ENTRIES  L3_PAGETABLE_ENTRIES

/*
 * Architecturally, physical addresses may be up to 52 bits. However, the
 * page-frame number (pfn) of a 52-bit address will not fit into a 32-bit
 * word. Instead we treat bits 44-51 of a pte as flag bits which are never
 * allowed to be set by a guest kernel. This 'limits' us to addressing 16TB
 * of physical memory on a 32-bit PAE system.
 */
#define PADDR_BITS              44
#define PADDR_MASK              ((1ULL << PADDR_BITS)-1)

#ifndef __ASSEMBLY__

#include <asm/types.h>

/* read access (should only be used for debug printk's) */
typedef u64 intpte_t;
#define PRIpte "016llx"

typedef struct { intpte_t l1; } l1_pgentry_t;
typedef struct { intpte_t l2; } l2_pgentry_t;
typedef struct { intpte_t l3; } l3_pgentry_t;
typedef l3_pgentry_t root_pgentry_t;

#endif /* !__ASSEMBLY__ */

#define pte_read_atomic(ptep) ({                              \
    intpte_t __pte = *(ptep), __npte;                         \
    while ( (__npte = cmpxchg(ptep, __pte, __pte)) != __pte ) \
        __pte = __npte;                                       \
    __pte; })
#define pte_write_atomic(ptep, pte) do {                      \
    intpte_t __pte = *(ptep), __npte;                         \
    while ( (__npte = cmpxchg(ptep, __pte, (pte))) != __pte ) \
        __pte = __npte;                                       \
} while ( 0 )
#define pte_write(ptep, pte) do {                             \
    u32 *__ptep_words = (u32 *)(ptep);                        \
    __ptep_words[0] = 0;                                      \
    wmb();                                                    \
    __ptep_words[1] = (pte) >> 32;                            \
    wmb();                                                    \
    __ptep_words[0] = (pte) >>  0;                            \
} while ( 0 )

/* root table */
#define root_get_pfn              l3e_get_pfn
#define root_get_flags            l3e_get_flags
#define root_get_intpte           l3e_get_intpte
#define root_empty                l3e_empty
#define root_from_paddr           l3e_from_paddr
#define PGT_root_page_table       PGT_l3_page_table

/* misc */
#define is_guest_l1_slot(s)    (1)
#define is_guest_l2_slot(d,t,s)                                            \
    ( !((t) & PGT_pae_xen_l2) ||                                           \
      ((s) < (L2_PAGETABLE_FIRST_XEN_SLOT & (L2_PAGETABLE_ENTRIES - 1))) )
#define is_guest_l3_slot(s)    (1)

/*
 * PTE pfn and flags:
 *  32-bit pfn   = (pte[43:12])
 *  32-bit flags = (pte[63:44],pte[11:0])
 */

#define _PAGE_NX_BIT (1U<<31)
#define _PAGE_NX     (cpu_has_nx ? _PAGE_NX_BIT : 0)

/* Extract flags into 32-bit integer, or turn 32-bit flags into a pte mask. */
#define get_pte_flags(x) (((int)((x) >> 32) & ~0xFFF) | ((int)(x) & 0xFFF))
#define put_pte_flags(x) (((intpte_t)((x) & ~0xFFF) << 32) | ((x) & 0xFFF))

#define L3_DISALLOW_MASK 0xFFFFF1FEU /* must-be-zero */

#endif /* __X86_32_PAGE_3LEVEL_H__ */