root/include/asm-x86/xen/page.h

INCLUDED FROM

DEFINITIONS

1. pfn_to_mfn
2. phys_to_machine_mapping_valid
3. mfn_to_pfn
4. phys_to_machine
5. machine_to_phys
6. mfn_to_local_pfn
7. pte_mfn
8. mfn_pte
9. pte_val_ma
10. __pte_ma

#ifndef ASM_X86__XEN__PAGE_H
#define ASM_X86__XEN__PAGE_H

#include <linux/pfn.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>

#include <xen/features.h>

/* Xen machine address */
typedef struct xmaddr {
        phys_addr_t maddr;
} xmaddr_t;

/* Xen pseudo-physical address */
typedef struct xpaddr {
        phys_addr_t paddr;
} xpaddr_t;

#define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
#define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })

/**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
#define INVALID_P2M_ENTRY       (~0UL)
#define FOREIGN_FRAME_BIT       (1UL<<31)
#define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)

/* Maximum amount of memory we can handle in a domain in pages */
#define MAX_DOMAIN_PAGES                                                \
    ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))


extern unsigned long get_phys_to_machine(unsigned long pfn);
extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);

static inline unsigned long pfn_to_mfn(unsigned long pfn)
{
        if (xen_feature(XENFEAT_auto_translated_physmap))
                return pfn;

        return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;
}

static inline int phys_to_machine_mapping_valid(unsigned long pfn)
{
        if (xen_feature(XENFEAT_auto_translated_physmap))
                return 1;

        return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
}

static inline unsigned long mfn_to_pfn(unsigned long mfn)
{
        unsigned long pfn;

        if (xen_feature(XENFEAT_auto_translated_physmap))
                return mfn;

#if 0
        if (unlikely((mfn >> machine_to_phys_order) != 0))
                return max_mapnr;
#endif

        pfn = 0;
        /*
         * The array access can fail (e.g., device space beyond end of RAM).
         * In such cases it doesn't matter what we return (we return garbage),
         * but we must handle the fault without crashing!
         */
        __get_user(pfn, &machine_to_phys_mapping[mfn]);

        return pfn;
}

static inline xmaddr_t phys_to_machine(xpaddr_t phys)
{
        unsigned offset = phys.paddr & ~PAGE_MASK;
        return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
}

static inline xpaddr_t machine_to_phys(xmaddr_t machine)
{
        unsigned offset = machine.maddr & ~PAGE_MASK;
        return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
}

/*
 * We detect special mappings in one of two ways:
 *  1. If the MFN is an I/O page then Xen will set the m2p entry
 *     to be outside our maximum possible pseudophys range.
 *  2. If the MFN belongs to a different domain then we will certainly
 *     not have MFN in our p2m table. Conversely, if the page is ours,
 *     then we'll have p2m(m2p(MFN))==MFN.
 * If we detect a special mapping then it doesn't have a 'struct page'.
 * We force !pfn_valid() by returning an out-of-range pointer.
 *
 * NB. These checks require that, for any MFN that is not in our reservation,
 * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 *
 * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 */
static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
{
        extern unsigned long max_mapnr;
        unsigned long pfn = mfn_to_pfn(mfn);
        if ((pfn < max_mapnr)
            && !xen_feature(XENFEAT_auto_translated_physmap)
            && (get_phys_to_machine(pfn) != mfn))
                return max_mapnr; /* force !pfn_valid() */
        /* XXX fixme; not true with sparsemem */
        return pfn;
}

/* VIRT <-> MACHINE conversion */
#define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
#define virt_to_mfn(v)          (pfn_to_mfn(PFN_DOWN(__pa(v))))
#define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))

static inline unsigned long pte_mfn(pte_t pte)
{
        return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
}

static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
{
        pte_t pte;

        pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
                (pgprot_val(pgprot) & __supported_pte_mask);

        return pte;
}

static inline pteval_t pte_val_ma(pte_t pte)
{
        return pte.pte;
}

static inline pte_t __pte_ma(pteval_t x)
{
        return (pte_t) { .pte = x };
}

#define pmd_val_ma(v) ((v).pmd)
#ifdef __PAGETABLE_PUD_FOLDED
#define pud_val_ma(v) ((v).pgd.pgd)
#else
#define pud_val_ma(v) ((v).pud)
#endif
#define __pmd_ma(x)     ((pmd_t) { (x) } )

#define pgd_val_ma(x)   ((x).pgd)


xmaddr_t arbitrary_virt_to_machine(void *address);
void make_lowmem_page_readonly(void *vaddr);
void make_lowmem_page_readwrite(void *vaddr);

#endif /* ASM_X86__XEN__PAGE_H */