// we only consider x86 w/o pae 
static void dump_guest_pgtable(CPUX86State *env)
{
    int i, j;
    target_ulong pde_addr, pte_addr;
    target_ulong phyaddr, phyaddr2;
    uint32_t pde, pte;

    pde_addr = (env->cr[3] & ~0xfff) & env->a20_mask;
    // first level page directory, iterate pde
    for (i = 0; i < NUM_ENTRY; ++i)
    {
        phyaddr = (pde_addr + i * 4) & env->a20_mask;
        pde = ldl_phys(phyaddr);
        pd[i] = pde;
        if (!(pde & PG_PRESENT_MASK))
            continue;

        pte_addr = (pde & ~0xfff) & env->a20_mask;
        // second level page table, iterate pte
        for (j = 0; j < NUM_ENTRY; ++j)
        {
            phyaddr2 = (pte_addr + j * 4) & env->a20_mask;
            pte = ldl_phys(phyaddr2);
            if (!(pte & PG_PRESENT_MASK))
                pt[i][j] = 0;
            pt[i][j] = pte;
        }
    }
}