C++ (Cpp) get_page_from_gfn_p2m Examples

Example #1

File: guest_walk.c Project: CPFL/xen

unsigned long hap_p2m_ga_to_gfn(GUEST_PAGING_LEVELS)(
    struct vcpu *v, struct p2m_domain *p2m, unsigned long cr3,
    paddr_t ga, uint32_t *pfec, unsigned int *page_order)
{
    uint32_t missing;
    mfn_t top_mfn;
    void *top_map;
    p2m_type_t p2mt;
    walk_t gw;
    unsigned long top_gfn;
    struct page_info *top_page;

    /* Get the top-level table's MFN */
    top_gfn = cr3 >> PAGE_SHIFT;
    top_page = get_page_from_gfn_p2m(p2m->domain, p2m, top_gfn,
                                     &p2mt, NULL, P2M_ALLOC | P2M_UNSHARE);
    if ( p2m_is_paging(p2mt) )
    {
        ASSERT(p2m_is_hostp2m(p2m));
        pfec[0] = PFEC_page_paged;
        if ( top_page )
            put_page(top_page);
        p2m_mem_paging_populate(p2m->domain, cr3 >> PAGE_SHIFT);
        return INVALID_GFN;
    }
    if ( p2m_is_shared(p2mt) )
    {
        pfec[0] = PFEC_page_shared;
        if ( top_page )
            put_page(top_page);
        return INVALID_GFN;
    }
    if ( !top_page )
    {
        pfec[0] &= ~PFEC_page_present;
        return INVALID_GFN;
    }
    top_mfn = _mfn(page_to_mfn(top_page));

    /* Map the top-level table and call the tree-walker */
    ASSERT(mfn_valid(mfn_x(top_mfn)));
    top_map = map_domain_page(mfn_x(top_mfn));
#if GUEST_PAGING_LEVELS == 3
    top_map += (cr3 & ~(PAGE_MASK | 31));
#endif
    missing = guest_walk_tables(v, p2m, ga, &gw, pfec[0], top_mfn, top_map);
    unmap_domain_page(top_map);
    put_page(top_page);

    /* Interpret the answer */
    if ( missing == 0 )
    {
        gfn_t gfn = guest_l1e_get_gfn(gw.l1e);
        struct page_info *page;
        page = get_page_from_gfn_p2m(p2m->domain, p2m, gfn_x(gfn), &p2mt,
                                     NULL, P2M_ALLOC | P2M_UNSHARE);
        if ( page )
            put_page(page);
        if ( p2m_is_paging(p2mt) )
        {
            ASSERT(p2m_is_hostp2m(p2m));
            pfec[0] = PFEC_page_paged;
            p2m_mem_paging_populate(p2m->domain, gfn_x(gfn));
            return INVALID_GFN;
        }
        if ( p2m_is_shared(p2mt) )
        {
            pfec[0] = PFEC_page_shared;
            return INVALID_GFN;
        }

        if ( page_order )
            *page_order = guest_walk_to_page_order(&gw);

        return gfn_x(gfn);
    }

    if ( missing & _PAGE_PRESENT )
        pfec[0] &= ~PFEC_page_present;

    if ( missing & _PAGE_INVALID_BITS ) 
        pfec[0] |= PFEC_reserved_bit;

    if ( missing & _PAGE_PAGED )
        pfec[0] = PFEC_page_paged;

    if ( missing & _PAGE_SHARED )
        pfec[0] = PFEC_page_shared;

    return INVALID_GFN;
}

Example #2

File: guest_walk.c Project: sheep/xen

unsigned long hap_p2m_ga_to_gfn(GUEST_PAGING_LEVELS)(
    struct vcpu *v, struct p2m_domain *p2m, unsigned long cr3,
    paddr_t ga, uint32_t *pfec, unsigned int *page_order)
{
    uint32_t missing;
    mfn_t top_mfn;
    void *top_map;
    p2m_type_t p2mt;
    walk_t gw;
    unsigned long top_gfn;
    struct page_info *top_page;

    /* Get the top-level table's MFN */
    top_gfn = cr3 >> PAGE_SHIFT;
    top_page = get_page_from_gfn_p2m(p2m->domain, p2m, top_gfn,
                                     &p2mt, NULL, P2M_ALLOC | P2M_UNSHARE);
    if ( p2m_is_paging(p2mt) )
    {
        ASSERT(p2m_is_hostp2m(p2m));
        pfec[0] = PFEC_page_paged;
        if ( top_page )
            put_page(top_page);
        p2m_mem_paging_populate(p2m->domain, cr3 >> PAGE_SHIFT);
        return gfn_x(INVALID_GFN);
    }
    if ( p2m_is_shared(p2mt) )
    {
        pfec[0] = PFEC_page_shared;
        if ( top_page )
            put_page(top_page);
        return gfn_x(INVALID_GFN);
    }
    if ( !top_page )
    {
        pfec[0] &= ~PFEC_page_present;
        goto out_tweak_pfec;
    }
    top_mfn = _mfn(page_to_mfn(top_page));

    /* Map the top-level table and call the tree-walker */
    ASSERT(mfn_valid(top_mfn));
    top_map = map_domain_page(top_mfn);
#if GUEST_PAGING_LEVELS == 3
    top_map += (cr3 & ~(PAGE_MASK | 31));
#endif
    missing = guest_walk_tables(v, p2m, ga, &gw, pfec[0], top_mfn, top_map);
    unmap_domain_page(top_map);
    put_page(top_page);

    /* Interpret the answer */
    if ( missing == 0 )
    {
        gfn_t gfn = guest_walk_to_gfn(&gw);
        struct page_info *page;
        page = get_page_from_gfn_p2m(p2m->domain, p2m, gfn_x(gfn), &p2mt,
                                     NULL, P2M_ALLOC | P2M_UNSHARE);
        if ( page )
            put_page(page);
        if ( p2m_is_paging(p2mt) )
        {
            ASSERT(p2m_is_hostp2m(p2m));
            pfec[0] = PFEC_page_paged;
            p2m_mem_paging_populate(p2m->domain, gfn_x(gfn));
            return gfn_x(INVALID_GFN);
        }
        if ( p2m_is_shared(p2mt) )
        {
            pfec[0] = PFEC_page_shared;
            return gfn_x(INVALID_GFN);
        }

        if ( page_order )
            *page_order = guest_walk_to_page_order(&gw);

        return gfn_x(gfn);
    }

    if ( missing & _PAGE_PRESENT )
        pfec[0] &= ~PFEC_page_present;

    if ( missing & _PAGE_INVALID_BITS ) 
        pfec[0] |= PFEC_reserved_bit;

    if ( missing & _PAGE_PKEY_BITS )
        pfec[0] |= PFEC_prot_key;

    if ( missing & _PAGE_PAGED )
        pfec[0] = PFEC_page_paged;

    if ( missing & _PAGE_SHARED )
        pfec[0] = PFEC_page_shared;

 out_tweak_pfec:
    /*
     * SDM Intel 64 Volume 3, Chapter Paging, PAGE-FAULT EXCEPTIONS:
     * The PFEC_insn_fetch flag is set only when NX or SMEP are enabled.
     */
    if ( !hvm_nx_enabled(v) && !hvm_smep_enabled(v) )
        pfec[0] &= ~PFEC_insn_fetch;

    return gfn_x(INVALID_GFN);
}