xc_domain_save.c

/******************************************************************************
 * xc_linux_save.c
 *
 * Save the state of a running Linux session.
 *
 * Copyright (c) 2003, K A Fraser.
 */

#include <inttypes.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>

#include "xc_private.h"
#include "xc_dom.h"
#include "xg_private.h"
#include "xg_save_restore.h"

#include <xen/hvm/params.h>
#include "xc_e820.h"

/*
** Default values for important tuning parameters. Can override by passing
** non-zero replacement values to xc_domain_save().
**
** XXX SMH: should consider if want to be able to override MAX_MBIT_RATE too.
**
*/
#define DEF_MAX_ITERS   29   /* limit us to 30 times round loop   */
#define DEF_MAX_FACTOR   3   /* never send more than 3x p2m_size  */
/* #define ADAPTIVE_SAVE */
#define TEST_WWS
#define TEST_MEMORY_DIRTY 

/* max mfn of the whole machine */
static unsigned long max_mfn;

/* virtual starting address of the hypervisor */
static unsigned long hvirt_start;

/* #levels of page tables used by the current guest */
static unsigned int pt_levels;

/* HVM: shared-memory bitmaps for getting log-dirty bits from qemu-dm */
static unsigned long *qemu_bitmaps[2];
static int qemu_active;
static int qemu_non_active;

/* number of pfns this guest has (i.e. number of entries in the P2M) */
static unsigned long p2m_size;

/* Live mapping of the table mapping each PFN to its current MFN. */
static xen_pfn_t *live_p2m = NULL;

/* Live mapping of system MFN to PFN table. */
static xen_pfn_t *live_m2p = NULL;
static unsigned long m2p_mfn0;

/* Address size of the guest */
unsigned int guest_width;

/* grep fodder: machine_to_phys */

#define mfn_to_pfn(_mfn)  (live_m2p[(_mfn)])

#define pfn_to_mfn(_pfn)                                            \
  ((xen_pfn_t) ((guest_width==8)                                    \
                ? (((uint64_t *)live_p2m)[(_pfn)])                  \
                : ((((uint32_t *)live_p2m)[(_pfn)]) == 0xffffffffU  \
                   ? (-1UL) : (((uint32_t *)live_p2m)[(_pfn)]))))

/*
 * Returns TRUE if the given machine frame number has a unique mapping
 * in the guest's pseudophysical map.
 */
#define MFN_IS_IN_PSEUDOPHYS_MAP(_mfn)          \
    (((_mfn) < (max_mfn)) &&                    \
     ((mfn_to_pfn(_mfn) < (p2m_size)) &&        \
      (pfn_to_mfn(mfn_to_pfn(_mfn)) == (_mfn))))

/*
** During (live) save/migrate, we maintain a number of bitmaps to track
** which pages we have to send, to fixup, and to skip.
*/

#define BITS_PER_LONG (sizeof(unsigned long) * 8)
#define BITS_TO_LONGS(bits) (((bits)+BITS_PER_LONG-1)/BITS_PER_LONG)
#define BITMAP_SIZE   (BITS_TO_LONGS(p2m_size) * sizeof(unsigned long))

#define BITMAP_ENTRY(_nr,_bmap) \
   ((volatile unsigned long *)(_bmap))[(_nr)/BITS_PER_LONG]

#define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)

static inline int test_bit (int nr, volatile void * addr)
{
    return (BITMAP_ENTRY(nr, addr) >> BITMAP_SHIFT(nr)) & 1;
}

static inline void clear_bit (int nr, volatile void * addr)
{
    BITMAP_ENTRY(nr, addr) &= ~(1UL << BITMAP_SHIFT(nr));
}

static inline void set_bit ( int nr, volatile void * addr)
{
    BITMAP_ENTRY(nr, addr) |= (1UL << BITMAP_SHIFT(nr));
}

/* Returns the hamming weight (i.e. the number of bits set) in a N-bit word */
static inline unsigned int hweight32(unsigned int w)
{
    unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
    res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
    res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
    res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
    return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
}

static inline int count_bits ( int nr, volatile void *addr)
{
    int i, count = 0;
    volatile unsigned long *p = (volatile unsigned long *)addr;
    /* We know that the array is padded to unsigned long. */
    for ( i = 0; i < (nr / (sizeof(unsigned long)*8)); i++, p++ )
        count += hweight32(*p);
    return count;
}

static uint64_t tv_to_us(struct timeval *new)
{
    return (new->tv_sec * 1000000) + new->tv_usec;
}

static uint64_t llgettimeofday(void)
{
    struct timeval now;
    gettimeofday(&now, NULL);
    return tv_to_us(&now);
}

static uint64_t tv_delta(struct timeval *new, struct timeval *old)
{
    return (((new->tv_sec - old->tv_sec)*1000000) +
            (new->tv_usec - old->tv_usec));
}

static int noncached_write(int fd, int live, void *buffer, int len)
{
    static int write_count = 0;
    int rc = (write_exact(fd, buffer, len) == 0) ? len : -1;

    write_count += len;
    if ( write_count >= (MAX_PAGECACHE_USAGE * PAGE_SIZE) )
    {
        /* Time to discard cache - dont care if this fails */
        discard_file_cache(fd, 0 /* no flush */);
        write_count = 0;
    }

    return rc;
}

#ifdef ADAPTIVE_SAVE

/*
** We control the rate at which we transmit (or save) to minimize impact
** on running domains (including the target if we're doing live migrate).
*/

#define MAX_MBIT_RATE    800      /* maximum transmit rate for migrate */
#define START_MBIT_RATE  400      /* initial transmit rate for migrate */

/* Scaling factor to convert between a rate (in Mb/s) and time (in usecs) */
#define RATE_TO_BTU      781250

/* Amount in bytes we allow ourselves to send in a burst */
#define BURST_BUDGET (100*1024)

/* We keep track of the current and previous transmission rate */
static int mbit_rate, ombit_rate = 0;

/* Have we reached the maximum transmission rate? */
#define RATE_IS_MAX() (mbit_rate == MAX_MBIT_RATE)

static inline void initialize_mbit_rate(void)
{
      mbit_rate = START_MBIT_RATE;
      /*  mbit_rate= 500; */

      }

static int ratewrite(int io_fd, int live, void *buf, int n)
{
    static int budget = 0;
    static int burst_time_us = -1;
    static struct timeval last_put = { 0 };
    struct timeval now;
    struct timespec delay;
    long long delta;

    if ( START_MBIT_RATE == 0 )
        return noncached_write(io_fd, live, buf, n);

    budget -= n;
    if ( budget < 0 )
    {
        if ( mbit_rate != ombit_rate )
        {
            burst_time_us = RATE_TO_BTU / mbit_rate;
            ombit_rate = mbit_rate;
            DPRINTF("rate limit: %d mbit/s burst budget %d slot time %d\n",
                    mbit_rate, BURST_BUDGET, burst_time_us);
        }
        if ( last_put.tv_sec == 0 )
        {
            budget += BURST_BUDGET;
            gettimeofday(&last_put, NULL);
        }
        else
        {
            while ( budget < 0 )
            {
                gettimeofday(&now, NULL);
                delta = tv_delta(&now, &last_put);
                while ( delta > burst_time_us )
                {
                    budget += BURST_BUDGET;
                    last_put.tv_usec += burst_time_us;
                    if ( last_put.tv_usec > 1000000 )
                    {
                    }
                    delta -= burst_time_us;
                }
                if ( budget > 0 )
                    break;
                delay.tv_sec = 0;
                delay.tv_nsec = 1000 * (burst_time_us - delta);
                while ( delay.tv_nsec > 0 )
                    if ( nanosleep(&delay, &delay) == 0 )
                        break;
            }
        }
    }
    return noncached_write(io_fd, live, buf, n);
}

#else /* ! ADAPTIVE SAVE */

#define RATE_IS_MAX() (0)
#define ratewrite(_io_fd, _live, _buf, _n) noncached_write((_io_fd), (_live), (_buf), (_n))
#define initialize_mbit_rate()

#endif

static int print_stats(int xc_handle, uint32_t domid, int pages_sent,
                       xc_shadow_op_stats_t *stats, int print)
{
    static struct timeval wall_last;
    static long long      d0_cpu_last;
    static long long      d1_cpu_last;

    struct timeval        wall_now;
    long long             wall_delta;
    long long             d0_cpu_now, d0_cpu_delta;
    long long             d1_cpu_now, d1_cpu_delta;

    gettimeofday(&wall_now, NULL);

    d0_cpu_now = xc_domain_get_cpu_usage(xc_handle, 0, /* FIXME */ 0)/1000;
    d1_cpu_now = xc_domain_get_cpu_usage(xc_handle, domid, /* FIXME */ 0)/1000;

    if ( (d0_cpu_now == -1) || (d1_cpu_now == -1) )
        DPRINTF("ARRHHH!!\n");

    wall_delta = tv_delta(&wall_now,&wall_last)/1000;
    if ( wall_delta == 0 )
        wall_delta = 1;

    d0_cpu_delta = (d0_cpu_now - d0_cpu_last)/1000;
    d1_cpu_delta = (d1_cpu_now - d1_cpu_last)/1000;

    if ( print )
        DPRINTF("delta %lldms, dom0 %d%%, target %d%%, sent %dMb/s, "
                "dirtied %dMb/s %" PRId32 " pages\n",
                wall_delta,
                (int)((d0_cpu_delta*100)/wall_delta),
                (int)((d1_cpu_delta*100)/wall_delta),
                (int)((pages_sent*PAGE_SIZE)/(wall_delta*(1000/8))),
                (int)((stats->dirty_count*PAGE_SIZE)/(wall_delta*(1000/8))),
                stats->dirty_count);

#ifdef ADAPTIVE_SAVE
    if ( ((stats->dirty_count*PAGE_SIZE)/(wall_delta*(1000/8))) > mbit_rate )
    {
      mbit_rate = (int)((stats->dirty_count*PAGE_SIZE)/(wall_delta*(1000/8))) +200; 

    /*      mbit_rate = 900; */
       if ( mbit_rate > MAX_MBIT_RATE )
            mbit_rate = MAX_MBIT_RATE;
    }
#endif

    d0_cpu_last = d0_cpu_now;
    d1_cpu_last = d1_cpu_now;
    wall_last   = wall_now;

    return 0;
}

static int analysis_phase(int xc_handle, uint32_t domid, int p2m_size,
                          unsigned long *arr, int runs)
{
    long long start, now;
    xc_shadow_op_stats_t stats;
    int j;

    start = llgettimeofday();

    for ( j = 0; j < runs; j++ )
    {
        int i;

        xc_shadow_control(xc_handle, domid, XEN_DOMCTL_SHADOW_OP_CLEAN,
                          arr, p2m_size, NULL, 0, NULL);
        DPRINTF("#Flush\n");
        for ( i = 0; i < 40; i++ )
        {
            usleep(50000);
            now = llgettimeofday();
            xc_shadow_control(xc_handle, domid, XEN_DOMCTL_SHADOW_OP_PEEK,
                              NULL, 0, NULL, 0, &stats);
            DPRINTF("now= %lld faults= %"PRId32" dirty= %"PRId32"\n",
                    ((now-start)+500)/1000,
                    stats.fault_count, stats.dirty_count);
        }
    }

    return -1;
}

static int suspend_and_state(int (*suspend)(void), int xc_handle, int io_fd,
                             int dom, xc_dominfo_t *info)
{
    if ( !(*suspend)() )
    {
        ERROR("Suspend request failed");
        return -1;
    }

    if ( (xc_domain_getinfo(xc_handle, dom, 1, info) != 1) ||
         !info->shutdown || (info->shutdown_reason != SHUTDOWN_suspend) )
    {
        ERROR("Domain not in suspended state");
        return -1;
    }

    return 0;
}

/*
** Map the top-level page of MFNs from the guest. The guest might not have
** finished resuming from a previous restore operation, so we wait a while for
** it to update the MFN to a reasonable value.
*/
static void *map_frame_list_list(int xc_handle, uint32_t dom,
                                 shared_info_any_t *shinfo)
{
    int count = 100;
    void *p;
    uint64_t fll = GET_FIELD(shinfo, arch.pfn_to_mfn_frame_list_list);

    while ( count-- && (fll == 0) )
    {
        usleep(10000);
        fll = GET_FIELD(shinfo, arch.pfn_to_mfn_frame_list_list);
    }

    if ( fll == 0 )
    {
        ERROR("Timed out waiting for frame list updated.");
        return NULL;
    }

    p = xc_map_foreign_range(xc_handle, dom, PAGE_SIZE, PROT_READ, fll);
    if ( p == NULL )
        ERROR("Couldn't map p2m_frame_list_list (errno %d)", errno);

    return p;
}

/*
** During transfer (or in the state file), all page-table pages must be
** converted into a 'canonical' form where references to actual mfns
** are replaced with references to the corresponding pfns.
**
** This function performs the appropriate conversion, taking into account
** which entries do not require canonicalization (in particular, those
** entries which map the virtual address reserved for the hypervisor).
*/
static int canonicalize_pagetable(unsigned long type, unsigned long pfn,
                           const void *spage, void *dpage)
{

    int i, pte_last, xen_start, xen_end, race = 0;
    uint64_t pte;

    /*
    ** We need to determine which entries in this page table hold
    ** reserved hypervisor mappings. This depends on the current
    ** page table type as well as the number of paging levels.
    */
    xen_start = xen_end = pte_last = PAGE_SIZE / ((pt_levels == 2) ?

4 : 8);

    if ( (pt_levels == 2) && (type == XEN_DOMCTL_PFINFO_L2TAB) )
        xen_start = (hvirt_start >> L2_PAGETABLE_SHIFT);

    if ( (pt_levels == 3) && (type == XEN_DOMCTL_PFINFO_L3TAB) )
        xen_start = L3_PAGETABLE_ENTRIES_PAE;

    /*
    ** In PAE only the L2 mapping the top 1GB contains Xen mappings.
    ** We can spot this by looking for the guest's mappingof the m2p.
    ** Guests must ensure that this check will fail for other L2s.
    */
    if ( (pt_levels == 3) && (type == XEN_DOMCTL_PFINFO_L2TAB) )
    {
        int hstart;
        uint64_t he;

        hstart = (hvirt_start >> L2_PAGETABLE_SHIFT_PAE) & 0x1ff;
        he = ((const uint64_t *) spage)[hstart];

        if ( ((he >> PAGE_SHIFT) & MFN_MASK_X86) == m2p_mfn0 )
        {
            /* hvirt starts with xen stuff... */
            xen_start = hstart;
        }
        else if ( hvirt_start != 0xf5800000 )
        {
            /* old L2s from before hole was shrunk... */
            hstart = (0xf5800000 >> L2_PAGETABLE_SHIFT_PAE) & 0x1ff;
            he = ((const uint64_t *) spage)[hstart];
            if ( ((he >> PAGE_SHIFT) & MFN_MASK_X86) == m2p_mfn0 )
                xen_start = hstart;
        }
    }

    if ( (pt_levels == 4) && (type == XEN_DOMCTL_PFINFO_L4TAB) )
    {
        /*
        ** XXX SMH: should compute these from hvirt_start (which we have)
        ** and hvirt_end (which we don't)
        */
        xen_start = 256;
        xen_end   = 272;
    }

    /* Now iterate through the page table, canonicalizing each PTE */
    for (i = 0; i < pte_last; i++ )
    {
        unsigned long pfn, mfn;

        if ( pt_levels == 2 )
            pte = ((const uint32_t*)spage)[i];
        else
            pte = ((const uint64_t*)spage)[i];

        if ( (i >= xen_start) && (i < xen_end) )
            pte = 0;

        if ( pte & _PAGE_PRESENT )
        {
            mfn = (pte >> PAGE_SHIFT) & MFN_MASK_X86;
            if ( !MFN_IS_IN_PSEUDOPHYS_MAP(mfn) )
            {
                /* This will happen if the type info is stale which
                   is quite feasible under live migration */
                pfn  = 0;  /* zap it - we'll retransmit this page later */
                /* XXX: We can't spot Xen mappings in compat-mode L2es
                 * from 64-bit tools, but the only thing in them is the
                 * compat m2p, so we quietly zap them.  This doesn't
                 * count as a race, so don't report it. */
                if ( !(type == XEN_DOMCTL_PFINFO_L2TAB
                       && sizeof (unsigned long) > guest_width) )
                     race = 1;  /* inform the caller; fatal if !live */
            }
            else
                pfn = mfn_to_pfn(mfn);

            pte &= ~MADDR_MASK_X86;
            pte |= (uint64_t)pfn << PAGE_SHIFT;

            /*
             * PAE guest L3Es can contain these flags when running on
             * a 64bit hypervisor. We zap these here to avoid any
             * surprise at restore time...
             */
            if ( (pt_levels == 3) &&
                 (type == XEN_DOMCTL_PFINFO_L3TAB) &&
                 (pte & (_PAGE_USER|_PAGE_RW|_PAGE_ACCESSED)) )
                pte &= ~(_PAGE_USER|_PAGE_RW|_PAGE_ACCESSED);
        }

        if ( pt_levels == 2 )
            ((uint32_t*)dpage)[i] = pte;
        else
            ((uint64_t*)dpage)[i] = pte;
    }

    return race;
}

static xen_pfn_t *xc_map_m2p(int xc_handle,
                                 unsigned long max_mfn,
                                 int prot)
{
    struct xen_machphys_mfn_list xmml;
    privcmd_mmap_entry_t *entries;
    unsigned long m2p_chunks, m2p_size;
    xen_pfn_t *m2p;
    xen_pfn_t *extent_start;
    int i;

    m2p = NULL;
    m2p_size   = M2P_SIZE(max_mfn);
    m2p_chunks = M2P_CHUNKS(max_mfn);

    xmml.max_extents = m2p_chunks;

    extent_start = calloc(m2p_chunks, sizeof(xen_pfn_t));
    if ( !extent_start )
    {
        ERROR("failed to allocate space for m2p mfns");
        goto err0;
    }
    set_xen_guest_handle(xmml.extent_start, extent_start);

    if ( xc_memory_op(xc_handle, XENMEM_machphys_mfn_list, &xmml) ||
         (xmml.nr_extents != m2p_chunks) )
    {
        ERROR("xc_get_m2p_mfns");
        goto err1;
    }

    entries = calloc(m2p_chunks, sizeof(privcmd_mmap_entry_t));
    if (entries == NULL)
    {
        ERROR("failed to allocate space for mmap entries");
        goto err1;
    }

    for ( i = 0; i < m2p_chunks; i++ )
        entries[i].mfn = extent_start[i];

    m2p = xc_map_foreign_ranges(xc_handle, DOMID_XEN,
			m2p_size, prot, M2P_CHUNK_SIZE,
			entries, m2p_chunks);
    if (m2p == NULL)
    {
        ERROR("xc_mmap_foreign_ranges failed");
        goto err2;
    }

    m2p_mfn0 = entries[0].mfn;

err2:
    free(entries);
err1:
    free(extent_start);

err0:
    return m2p;
}

static xen_pfn_t *map_and_save_p2m_table(int xc_handle,
                                         int io_fd,
                                         uint32_t dom,
                                         unsigned long p2m_size,
                                         shared_info_any_t *live_shinfo)
{
    vcpu_guest_context_any_t ctxt;

    /* Double and single indirect references to the live P2M table */
    void *live_p2m_frame_list_list = NULL;
    void *live_p2m_frame_list = NULL;

    /* Copies of the above. */
    xen_pfn_t *p2m_frame_list_list = NULL;
    xen_pfn_t *p2m_frame_list = NULL;

    /* The mapping of the live p2m table itself */
    xen_pfn_t *p2m = NULL;

    int i, success = 0;

    live_p2m_frame_list_list = map_frame_list_list(xc_handle, dom,
                                                   live_shinfo);
    if ( !live_p2m_frame_list_list )
        goto out;

    /* Get a local copy of the live_P2M_frame_list_list */
    if ( !(p2m_frame_list_list = malloc(PAGE_SIZE)) )
    {
        ERROR("Couldn't allocate p2m_frame_list_list array");
        goto out;
    }
    memcpy(p2m_frame_list_list, live_p2m_frame_list_list, PAGE_SIZE);

    /* Canonicalize guest's unsigned long vs ours */
    if ( guest_width > sizeof(unsigned long) )
        for ( i = 0; i < PAGE_SIZE/sizeof(unsigned long); i++ )
            if ( i < PAGE_SIZE/guest_width )
                p2m_frame_list_list[i] = ((uint64_t *)p2m_frame_list_list)[i];
            else
                p2m_frame_list_list[i] = 0;
    else if ( guest_width < sizeof(unsigned long) )
        for ( i = PAGE_SIZE/sizeof(unsigned long) - 1; i >= 0; i-- )
            p2m_frame_list_list[i] = ((uint32_t *)p2m_frame_list_list)[i];

    live_p2m_frame_list =
        xc_map_foreign_batch(xc_handle, dom, PROT_READ,
                             p2m_frame_list_list,
                             P2M_FLL_ENTRIES);
    if ( !live_p2m_frame_list )
    {
        ERROR("Couldn't map p2m_frame_list");
        goto out;
    }

    /* Get a local copy of the live_P2M_frame_list */
    if ( !(p2m_frame_list = malloc(P2M_TOOLS_FL_SIZE)) )
    {
        ERROR("Couldn't allocate p2m_frame_list array");
        goto out;
    }
    memset(p2m_frame_list, 0, P2M_TOOLS_FL_SIZE);
    memcpy(p2m_frame_list, live_p2m_frame_list, P2M_GUEST_FL_SIZE);

    /* Canonicalize guest's unsigned long vs ours */
    if ( guest_width > sizeof(unsigned long) )
        for ( i = 0; i < P2M_FL_ENTRIES; i++ )
            p2m_frame_list[i] = ((uint64_t *)p2m_frame_list)[i];
    else if ( guest_width < sizeof(unsigned long) )
        for ( i = P2M_FL_ENTRIES - 1; i >= 0; i-- )
            p2m_frame_list[i] = ((uint32_t *)p2m_frame_list)[i];

    /* Map all the frames of the pfn->mfn table. For migrate to succeed,
       the guest must not change which frames are used for this purpose.
       (its not clear why it would want to change them, and we'll be OK
       from a safety POV anyhow. */

    p2m = xc_map_foreign_batch(xc_handle, dom, PROT_READ,
                               p2m_frame_list,
                               P2M_FL_ENTRIES);
    if ( !p2m )
    {
        ERROR("Couldn't map p2m table");
        goto out;
    }
    live_p2m = p2m; /* So that translation macros will work */

    /* Canonicalise the pfn-to-mfn table frame-number list. */
    for ( i = 0; i < p2m_size; i += FPP )
    {
        if ( !MFN_IS_IN_PSEUDOPHYS_MAP(p2m_frame_list[i/FPP]) )
        {
            ERROR("Frame# in pfn-to-mfn frame list is not in pseudophys");
            ERROR("entry %d: p2m_frame_list[%ld] is 0x%"PRIx64", max 0x%lx",
                  i, i/FPP, (uint64_t)p2m_frame_list[i/FPP], max_mfn);
            if ( p2m_frame_list[i/FPP] < max_mfn )
            {
                ERROR("m2p[0x%"PRIx64"] = 0x%"PRIx64,
                      (uint64_t)p2m_frame_list[i/FPP],
                      (uint64_t)live_m2p[p2m_frame_list[i/FPP]]);
                ERROR("p2m[0x%"PRIx64"] = 0x%"PRIx64,
                      (uint64_t)live_m2p[p2m_frame_list[i/FPP]],
                      (uint64_t)p2m[live_m2p[p2m_frame_list[i/FPP]]]);

            }
            goto out;
        }
        p2m_frame_list[i/FPP] = mfn_to_pfn(p2m_frame_list[i/FPP]);
    }

    if ( xc_vcpu_getcontext(xc_handle, dom, 0, &ctxt) )
    {
        ERROR("Could not get vcpu context");
        goto out;
    }

    /*
     * Write an extended-info structure to inform the restore code that
     * a PAE guest understands extended CR3 (PDPTs above 4GB). Turns off
     * slow paths in the restore code.
     */
    {
        unsigned long signature = ~0UL;
        uint32_t chunk1_sz = ((guest_width==8)
                              ?

sizeof(ctxt.x64)
                              : sizeof(ctxt.x32));
        uint32_t chunk2_sz = 0;
        uint32_t tot_sz    = (chunk1_sz + 8) + (chunk2_sz + 8);
        if ( write_exact(io_fd, &signature, sizeof(signature)) ||
             write_exact(io_fd, &tot_sz, sizeof(tot_sz)) ||
             write_exact(io_fd, "vcpu", 4) ||
             write_exact(io_fd, &chunk1_sz, sizeof(chunk1_sz)) ||
             write_exact(io_fd, &ctxt, chunk1_sz) ||
             write_exact(io_fd, "extv", 4) ||
             write_exact(io_fd, &chunk2_sz, sizeof(chunk2_sz)) )
        {
            PERROR("write: extended info");
            goto out;
        }
    }

    if ( write_exact(io_fd, p2m_frame_list,
                     P2M_FL_ENTRIES * sizeof(xen_pfn_t)) )
    {
        PERROR("write: p2m_frame_list");
        goto out;
    }

    success = 1;

 out:

    if ( !success && p2m )
        munmap(p2m, P2M_FLL_ENTRIES * PAGE_SIZE);

    if ( live_p2m_frame_list_list )
        munmap(live_p2m_frame_list_list, PAGE_SIZE);

    if ( live_p2m_frame_list )
        munmap(live_p2m_frame_list, P2M_FLL_ENTRIES * PAGE_SIZE);

    if ( p2m_frame_list_list )
        free(p2m_frame_list_list);

    if ( p2m_frame_list )
        free(p2m_frame_list);

    return success ?

p2m : NULL;
}

int xc_domain_save(int xc_handle, int io_fd, uint32_t dom, uint32_t max_iters,
                   uint32_t max_factor, uint32_t flags, int (*suspend)(void),
                   int hvm, void *(*init_qemu_maps)(int, unsigned),
                   void (*qemu_flip_buffer)(int, int))
{
    xc_dominfo_t info;
    DECLARE_DOMCTL;
    unsigned long count=0;

    int rc = 1, frc, i, j, last_iter, iter = 0;
    int live  = (flags & XCFLAGS_LIVE);
    int debug = (flags & XCFLAGS_DEBUG);
    int race = 0, sent_last_iter, skip_this_iter;

    /* The new domain's shared-info frame number. */
    unsigned long shared_info_frame;

    /* A copy of the CPU context of the guest. */
    vcpu_guest_context_any_t ctxt;

    /* A table containing the type of each PFN (/not/ MFN!). */
    unsigned long *pfn_type = NULL;
    unsigned long *pfn_batch = NULL;

    /* A copy of one frame of guest memory. */
    char page[PAGE_SIZE];

    /* Live mapping of shared info structure */
    shared_info_any_t *live_shinfo = NULL;

    /* base of the region in which domain memory is mapped */
    unsigned char *region_base = NULL;

    /* bitmap of pages:
       - that should be sent this iteration (unless later marked as skip);
       - to skip this iteration because already dirty;
       - to fixup by sending at the end if not already resent; */
    unsigned long *to_send = NULL, *to_skip = NULL, *to_fix = NULL;

    xc_shadow_op_stats_t stats;

    unsigned long needed_to_fix = 0;
    unsigned long total_sent    = 0;

    uint64_t vcpumap = 1ULL;

    /* HVM: a buffer for holding HVM context */
    uint32_t hvm_buf_size = 0;
    uint8_t *hvm_buf = NULL;

    /* HVM: magic frames for ioreqs and xenstore comms. */
    uint64_t magic_pfns[3]; /* ioreq_pfn, bufioreq_pfn, store_pfn */

    unsigned long mfn;

    /* If no explicit control parameters given, use defaults */
    max_iters  = max_iters  ?

: DEF_MAX_ITERS;
    max_factor = max_factor ? : DEF_MAX_FACTOR;

    initialize_mbit_rate();

    if ( !get_platform_info(xc_handle, dom,
                            &max_mfn, &hvirt_start, &pt_levels, &guest_width) )
    {
        ERROR("Unable to get platform info.");
        return 1;
    }

    if ( xc_domain_getinfo(xc_handle, dom, 1, &info) != 1 )
    {
        ERROR("Could not get domain info");
        return 1;
    }

    shared_info_frame = info.shared_info_frame;

    /* Map the shared info frame */
    if ( !hvm )
    {
        live_shinfo = xc_map_foreign_range(xc_handle, dom, PAGE_SIZE,
                                           PROT_READ, shared_info_frame);
        if ( !live_shinfo )
        {
            ERROR("Couldn't map live_shinfo");
            goto out;
        }
    }

    /* Get the size of the P2M table */
    p2m_size = xc_memory_op(xc_handle, XENMEM_maximum_gpfn, &dom) + 1;

    /* Setup to_send / to_fix and to_skip bitmaps */
    to_send = xg_memalign(PAGE_SIZE, ROUNDUP(BITMAP_SIZE, PAGE_SHIFT));
    to_fix  = calloc(1, BITMAP_SIZE);
    to_skip = xg_memalign(PAGE_SIZE, ROUNDUP(BITMAP_SIZE, PAGE_SHIFT)); 

    if ( !to_send || !to_fix || !to_skip )
    {
        ERROR("Couldn't allocate to_send array");
        goto out;
    }
/***************************************************begin of testing memory writable work set**********************************/
#ifdef TEST_WWS

    if ( lock_pages(to_send, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_send");
        return 1;
    }

    /* (to fix is local only) */
    if ( lock_pages(to_skip, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_skip");
        return 1;
    }

    /*Enable log-dirty mode. */
    if ( xc_shadow_control(xc_handle, dom,
                               XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                               NULL, 0, NULL, 0, NULL) < 0 )
    {
            /* log-dirty already enabled? There's no test op,
               so attempt to disable then reenable it */
        frc = xc_shadow_control(xc_handle, dom, XEN_DOMCTL_SHADOW_OP_OFF,
                                    NULL, 0, NULL, 0, NULL);
        if ( frc >= 0 )
        {
            frc = xc_shadow_control(xc_handle, dom,
                                        XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                                        NULL, 0, NULL, 0, NULL);
        }

        if ( frc < 0 )
        {
            ERROR("Couldn't enable shadow mode (rc %d) (errno %d)", frc, errno );
            goto out;
        }
    }

            if ( xc_shadow_control(xc_handle, dom,
                                   XEN_DOMCTL_SHADOW_OP_CLEAN, to_send,
                                   p2m_size, NULL, 0, &stats) != p2m_size )
            {
                ERROR("Error flushing shadow PT");
                goto out;
            }
	    if ( xc_shadow_control(xc_handle, dom,
                                   XEN_DOMCTL_SHADOW_OP_CLEAN, to_fix,
                                   p2m_size, NULL, 0, &stats) != p2m_size )
            {
                ERROR("Error flushing shadow PT");
                goto out;
            }

	  sleep(10);
        count=0;
	frc = xc_shadow_control(
                           xc_handle, dom, XEN_DOMCTL_SHADOW_OP_PEEK, to_send,
                           p2m_size, NULL, 0, NULL);
            if ( frc != p2m_size )
            {
                ERROR("Error peeking to_send shadow bitmap");
                goto out;
            }

		for(j=0;j<p2m_size;j++)
		{
			if( test_bit(j, to_send)==1 )
			{
			    count++;
			}
		}
	DPRINTF(" \n delay time 10(s), To_send page number is, %ld",  count);

	count=0;
	frc = xc_shadow_control(
                           xc_handle, dom, XEN_DOMCTL_SHADOW_OP_PEEK, to_skip,
                           p2m_size, NULL, 0, NULL);
            if ( frc != p2m_size )
            {
                ERROR("Error peeking to_skip shadow bitmap");
                goto out;
            }

		for(j=0;j<p2m_size;j++)
		{
			if( test_bit(j, to_skip)==1 )
			{
			    count++;
			}
		}
	DPRINTF(" \n delay time 10(s), To_skip page number is, %ld",  count);
#endif
/***************************************************end of testing memory writable work set**********************************/

#ifdef TEST_MEMORY_DIRTY
/***************************************************begin of testing memory dirty rate **********************************/
/** struct timeval time_start, time_end;
 long long testtime;
**/

	if ( lock_pages(to_send, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_send");
        return 1;
    }

    /* (to fix is local only) */
    if ( lock_pages(to_skip, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_skip");
        return 1;
    }

    /*Enable log-dirty mode. */
    if ( xc_shadow_control(xc_handle, dom,
                               XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                               NULL, 0, NULL, 0, NULL) < 0 )
    {
            /* log-dirty already enabled?

There's no test op,
               so attempt to disable then reenable it */
        frc = xc_shadow_control(xc_handle, dom, XEN_DOMCTL_SHADOW_OP_OFF,
                                    NULL, 0, NULL, 0, NULL);
        if ( frc >= 0 )
        {
            frc = xc_shadow_control(xc_handle, dom,
                                        XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                                        NULL, 0, NULL, 0, NULL);
        }

        if ( frc < 0 )
        {
            ERROR("Couldn't enable shadow mode (rc %d) (errno %d)", frc, errno );
            goto out;
        }
    }

	for(i=0;i<120;i++)
	{

		count=0;

            if ( xc_shadow_control(xc_handle, dom,
                                   XEN_DOMCTL_SHADOW_OP_CLEAN, to_send,
                                   p2m_size, NULL, 0, &stats) != p2m_size )
            {
                ERROR("Error flushing shadow PT");
                goto out;
            }

		usleep(500000);

            frc = xc_shadow_control(
                           xc_handle, dom, XEN_DOMCTL_SHADOW_OP_PEEK, to_send,
                           p2m_size, NULL, 0, NULL);
            if ( frc != p2m_size )
            {
                ERROR("Error peeking shadow bitmap");
                goto out;
            }

		for(j=0;j<p2m_size;j++)
		{
			if( test_bit(j, to_send)==1 )
			{
			    count++;
			}
		}

		/*DPRINTF(" \n %d,delay time(ms), %ld,  dirty page number is, %ld, normalized dirty rate,%f", i, delay/1000, count, new_rate); */
		DPRINTF(" \n %d,peeking delay time(500ms),  dirty page number is, %ld", i, count);

		}
/*************************************************** end of testing memory dirty rate **********************************/
#endif

/* Domain is still running at this point */

       if ( live )
    {
        /* Live suspend. Enable log-dirty mode. */
        if ( xc_shadow_control(xc_handle, dom,
                               XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                               NULL, 0, NULL, 0, NULL) < 0 )
        {
            /* log-dirty already enabled? There's no test op,
               so attempt to disable then reenable it */
            frc = xc_shadow_control(xc_handle, dom, XEN_DOMCTL_SHADOW_OP_OFF,
                                    NULL, 0, NULL, 0, NULL);
            if ( frc >= 0 )
            {
                frc = xc_shadow_control(xc_handle, dom,
                                        XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                                        NULL, 0, NULL, 0, NULL);
            }

            if ( frc < 0 )
            {
                ERROR("Couldn't enable shadow mode (rc %d) (errno %d)", frc, errno );
                goto out;
            }
        }

        if ( hvm )
        {
            /* Get qemu-dm logging dirty pages too */
            void *seg = init_qemu_maps(dom, BITMAP_SIZE);
            qemu_bitmaps[0] = seg;
            qemu_bitmaps[1] = seg + BITMAP_SIZE;
            qemu_active = 0;
            qemu_non_active = 1;
        }
    }
    else
    {
        /* This is a non-live suspend. Suspend the domain .*/
        if ( suspend_and_state(suspend, xc_handle, io_fd, dom, &info) )
        {
            ERROR("Domain appears not to have suspended");
            goto out;
        }
    }

    last_iter = !live;

    /* pretend we sent all the pages last iteration */
    sent_last_iter = p2m_size;

    memset(to_send, 0xff, BITMAP_SIZE);

    if ( lock_pages(to_send, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_send");
        return 1;
    } 

    /* (to fix is local only) */
    if ( lock_pages(to_skip, BITMAP_SIZE) )
    {
        ERROR("Unable to lock to_skip");
        return 1;
    }

    if ( hvm )
    {
        /* Need another buffer for HVM context */
        hvm_buf_size = xc_domain_hvm_getcontext(xc_handle, dom, 0, 0);
        if ( hvm_buf_size == -1 )
        {
            ERROR("Couldn't get HVM context size from Xen");
            goto out;
        }
        hvm_buf = malloc(hvm_buf_size);
        if ( !hvm_buf )
        {
            ERROR("Couldn't allocate memory");
            goto out;
        }
    }

    analysis_phase(xc_handle, dom, p2m_size, to_skip, 0);

    pfn_type   = xg_memalign(PAGE_SIZE, ROUNDUP(
                              MAX_BATCH_SIZE * sizeof(*pfn_type), PAGE_SHIFT));
    pfn_batch  = calloc(MAX_BATCH_SIZE, sizeof(*pfn_batch));
    if ( (pfn_type == NULL) || (pfn_batch == NULL) )
    {
        ERROR("failed to alloc memory for pfn_type and/or pfn_batch arrays");
        errno = ENOMEM;
        goto out;
    }
    memset(pfn_type, 0,
           ROUNDUP(MAX_BATCH_SIZE * sizeof(*pfn_type), PAGE_SHIFT));

    if ( lock_pages(pfn_type, MAX_BATCH_SIZE * sizeof(*pfn_type)) )
    {
        ERROR("Unable to lock pfn_type array");
        goto out;
    }

    /* Setup the mfn_to_pfn table mapping */
    if ( !(live_m2p = xc_map_m2p(xc_handle, max_mfn, PROT_READ)) )
    {
        ERROR("Failed to map live M2P table");
        goto out;
    }

    /* Start writing out the saved-domain record. */
    if ( write_exact(io_fd, &p2m_size, sizeof(unsigned long)) )
    {
        PERROR("write: p2m_size");
        goto out;
    }

    if ( !hvm )
    {
        int err = 0;

        /* Map the P2M table, and write the list of P2M frames */
        live_p2m = map_and_save_p2m_table(xc_handle, io_fd, dom,
                                          p2m_size, live_shinfo);
        if ( live_p2m == NULL )
        {
            ERROR("Failed to map/save the p2m frame list");
            goto out;
        }

        /*
         * Quick belt and braces sanity check.
         */

        for ( i = 0; i < p2m_size; i++ )
        {
            mfn = pfn_to_mfn(i);
            if( (mfn != INVALID_P2M_ENTRY) && (mfn_to_pfn(mfn) != i) )
            {
                DPRINTF("i=0x%x mfn=%lx live_m2p=%lx\n", i,
                        mfn, mfn_to_pfn(mfn));
                err++;
            }
        }
        DPRINTF("Had %d unexplained entries in p2m table\n", err);
    }

    print_stats(xc_handle, dom, 0, &stats, 0);

    /* Now write out each data page, canonicalising page tables as we go... */
    for ( ; ; )
    {
        unsigned int prev_pc, sent_this_iter, N, batch, run;

        iter++;
        sent_this_iter = 0;
        skip_this_iter = 0;
        prev_pc = 0;
        N = 0;

        DPRINTF("Saving memory pages: iter %d   0%%", iter);

        while ( N < p2m_size )
        {
            unsigned int this_pc = (N * 100) / p2m_size;

            if ( (this_pc - prev_pc) >= 5 )
            {
                DPRINTF("\b\b\b\b%3d%%", this_pc);
                prev_pc = this_pc;
            }

            if ( !last_iter )
            {
                /* Slightly wasteful to peek the whole array evey time,
                   but this is fast enough for the moment. */
                frc = xc_shadow_control(
                    xc_handle, dom, XEN_DOMCTL_SHADOW_OP_PEEK, to_skip,
                    p2m_size, NULL, 0, NULL);
                if ( frc != p2m_size )
                {
                    ERROR("Error peeking shadow bitmap");
                    goto out;
                }
            }

            /* load pfn_type[] with the mfn of all the pages we're doing in
               this batch. */
            for  ( batch = 0;
                   (batch < MAX_BATCH_SIZE) && (N < p2m_size);
                   N++ )
            {
                int n = N;

                if ( debug )
                {
                    DPRINTF("%d pfn= %08lx mfn= %08lx %d",
                            iter, (unsigned long)n,
                            hvm ?

0 : pfn_to_mfn(n),
                            test_bit(n, to_send));
                    if ( !hvm && is_mapped(pfn_to_mfn(n)) )
                        DPRINTF("  [mfn]= %08lx",
                                mfn_to_pfn(pfn_to_mfn(n)&0xFFFFF));
                    DPRINTF("\n");
                }
                if ( !last_iter &&
                     test_bit(n, to_send) &&
                     test_bit(n, to_skip) )
                    skip_this_iter++; /* stats keeping */

                if ( !((test_bit(n, to_send) && !test_bit(n, to_skip)) ||
                       (test_bit(n, to_send) && last_iter) ||
                       (test_bit(n, to_fix)  && last_iter)) )
                    continue;

                /*
                ** we get here if:
                **  1. page is marked to_send & hasn't already been re-dirtied
                **  2. (ignore to_skip in last iteration)
                **  3. add in pages that still need fixup (net bufs)
                */

                pfn_batch[batch] = n;

                /* Hypercall interfaces operate in PFNs for HVM guests
                * and MFNs for PV guests */
                if ( hvm )
                    pfn_type[batch] = n;
                else
                    pfn_type[batch] = pfn_to_mfn(n);

                if ( !is_mapped(pfn_type[batch]) )
                {
                    /*
                    ** not currently in psuedo-physical map -- set bit
                    ** in to_fix since we must send this page in last_iter
                    ** unless its sent sooner anyhow, or it never enters
                    ** pseudo-physical map (e.g. for ballooned down doms)
                    */
                    set_bit(n, to_fix);
                    continue;
                }

                if ( last_iter &&
                     test_bit(n, to_fix) &&
                     !test_bit(n, to_send) )
                {
                    needed_to_fix++;
                    DPRINTF("Fix! iter %d, pfn %x. mfn %lx\n",
                            iter, n, pfn_type[batch]);
                }

                clear_bit(n, to_fix);

                batch++;
            }

            if ( batch == 0 )
                goto skip; /* vanishingly unlikely... */

            region_base = xc_map_foreign_batch(
                xc_handle, dom, PROT_READ, pfn_type, batch);
            if ( region_base == NULL )
            {
                ERROR("map batch failed");
                goto out;
            }

            if ( hvm )
            {
                /* Look for and skip completely empty batches. */
                for ( j = 0; j < batch; j++ )
                    if ( (pfn_type[j] & XEN_DOMCTL_PFINFO_LTAB_MASK) !=
                         XEN_DOMCTL_PFINFO_XTAB )
                        break;
                if ( j == batch )
                {
                    munmap(region_base, batch*PAGE_SIZE);
                    continue; /* bail on this batch: no valid pages */
                }
            }
            else
            {
                /* Get page types */
                for ( j = 0; j < batch; j++ )
                    ((uint32_t *)pfn_type)[j] = pfn_type[j];
                if ( xc_get_pfn_type_batch(xc_handle, dom, batch,
                                           (uint32_t *)pfn_type) )
                {
                    ERROR("get_pfn_type_batch failed");
                    goto out;
                }
                for ( j = batch-1; j >= 0; j-- )
                    pfn_type[j] = ((uint32_t *)pfn_type)[j];

                for ( j = 0; j < batch; j++ )
                {

                    if ( (pfn_type[j] & XEN_DOMCTL_PFINFO_LTAB_MASK) ==
                         XEN_DOMCTL_PFINFO_XTAB )
                    {
                        DPRINTF("type fail: page %i mfn %08lx\n",
                                j, pfn_type[j]);
                        continue;
                    }

                    if ( debug )
                        DPRINTF("%d pfn= %08lx mfn= %08lx [mfn]= %08lx"
                                " sum= %08lx\n",
                                iter,
                                (pfn_type[j] & XEN_DOMCTL_PFINFO_LTAB_MASK) |
                                pfn_batch[j],
                                pfn_type[j],
                                mfn_to_pfn(pfn_type[j] &
                                           ~XEN_DOMCTL_PFINFO_LTAB_MASK),
                                csum_page(region_base + (PAGE_SIZE*j)));

                    /* canonicalise mfn->pfn */
                    pfn_type[j] = (pfn_type[j] & XEN_DOMCTL_PFINFO_LTAB_MASK) |
                        pfn_batch[j];
                }
            }

            if ( write_exact(io_fd, &batch, sizeof(unsigned int)) )
            {
                PERROR("Error when writing to state file (2)");
                goto out;
            }

            if ( write_exact(io_fd, pfn_type, sizeof(unsigned long)*batch) )
            {
                PERROR("Error when writing to state file (3)");
                goto out;
            }

            /* entering this loop, pfn_type is now in pfns (Not mfns) */
            run = 0;
            for ( j = 0; j < batch; j++ )
            {
                unsigned long pfn, pagetype;
                void *spage = (char *)region_base + (PAGE_SIZE*j);

                pfn      = pfn_type[j] & ~XEN_DOMCTL_PFINFO_LTAB_MASK;
                pagetype = pfn_type[j] &  XEN_DOMCTL_PFINFO_LTAB_MASK;

                if ( pagetype != 0 )
                {
                    /* If the page is not a normal data page, write out any
                       run of pages we may have previously acumulated */
                    if ( run )
                    {
                        if ( ratewrite(io_fd, live,
                                       (char*)region_base+(PAGE_SIZE*(j-run)),
                                       PAGE_SIZE*run) != PAGE_SIZE*run )
                        {
                            ERROR("Error when writing to state file (4a)"
                                  " (errno %d)", errno);
                            goto out;
                        }
                        run = 0;
                    }
                }

                /* skip pages that aren't present */
                if ( pagetype == XEN_DOMCTL_PFINFO_XTAB )
                    continue;

                pagetype &= XEN_DOMCTL_PFINFO_LTABTYPE_MASK;

                if ( (pagetype >= XEN_DOMCTL_PFINFO_L1TAB) &&
                     (pagetype <= XEN_DOMCTL_PFINFO_L4TAB) )
                {
                    /* We have a pagetable page: need to rewrite it. */
                    race =
                        canonicalize_pagetable(pagetype, pfn, spage, page); 

                    if ( race && !live )
                    {
                        ERROR("Fatal PT race (pfn %lx, type %08lx)", pfn,
                              pagetype);
                        goto out;
                    }

                    if ( ratewrite(io_fd, live, page, PAGE_SIZE) != PAGE_SIZE )
                    {
                        ERROR("Error when writing to state file (4b)"
                              " (errno %d)", errno);
                        goto out;
                    }
                }
                else
                {
                    /* We have a normal page: accumulate it for writing. */
                    run++;
                }
            } /* end of the write out for this batch */

            if ( run )
            {
                /* write out the last accumulated run of pages */
                if ( ratewrite(io_fd, live,
                               (char*)region_base+(PAGE_SIZE*(j-run)),
                               PAGE_SIZE*run) != PAGE_SIZE*run )
                {
                    ERROR("Error when writing to state file (4c)"
                          " (errno %d)", errno);
                    goto out;
                }
            }

            sent_this_iter += batch;

            munmap(region_base, batch*PAGE_SIZE);

        } /* end of this while loop for this iteration */

      skip:

        total_sent += sent_this_iter;

        DPRINTF("\r %d: sent %d, skipped %d, ",
                iter, sent_this_iter, skip_this_iter );

        if ( last_iter )
        {
            print_stats( xc_handle, dom, sent_this_iter, &stats, 1);

            DPRINTF("Total pages sent= %ld (%.2fx)\n",
                    total_sent, ((float)total_sent)/p2m_size );
            DPRINTF("(of which %ld were fixups)\n", needed_to_fix  );
        }

        if ( last_iter && debug )
        {
            int minusone = -1;
            memset(to_send, 0xff, BITMAP_SIZE);
            debug = 0;
            DPRINTF("Entering debug resend-all mode\n");

            /* send "-1" to put receiver into debug mode */
            if ( write_exact(io_fd, &minusone, sizeof(int)) )
            {
                PERROR("Error when writing to state file (6)");
                goto out;
            }

            continue;
        }

        if ( last_iter )
            break;

        if ( live )
        {
            if ( ((sent_this_iter > sent_last_iter) && RATE_IS_MAX()) ||
                 (iter >= max_iters) ||
                 (sent_this_iter+skip_this_iter < 50) ||
                 (total_sent > p2m_size*max_factor) )
            {
                DPRINTF("Start last iteration\n");
                last_iter = 1;

                if ( suspend_and_state(suspend, xc_handle, io_fd, dom, &info) )
                {
                    ERROR("Domain appears not to have suspended");
                    goto out;
                }

                DPRINTF("SUSPEND shinfo %08lx\n", info.shared_info_frame);
            }

            if ( xc_shadow_control(xc_handle, dom,
                                   XEN_DOMCTL_SHADOW_OP_CLEAN, to_send,
                                   p2m_size, NULL, 0, &stats) != p2m_size )
            {
                ERROR("Error flushing shadow PT");
                goto out;
            }

            if ( hvm )
            {
                /* Pull in the dirty bits from qemu-dm too */
                if ( !last_iter )
                {
                    qemu_active = qemu_non_active;
                    qemu_non_active = qemu_active ? 0 : 1;
                    qemu_flip_buffer(dom, qemu_active);
                    for ( j = 0; j < BITMAP_SIZE / sizeof(unsigned long); j++ )
                    {
                        to_send[j] |= qemu_bitmaps[qemu_non_active][j];
                        qemu_bitmaps[qemu_non_active][j] = 0;
                    }
                }
                else
                {
                    for ( j = 0; j < BITMAP_SIZE / sizeof(unsigned long); j++ )
                        to_send[j] |= qemu_bitmaps[qemu_active][j];
                }
            }

            sent_last_iter = sent_this_iter;

            print_stats(xc_handle, dom, sent_this_iter, &stats, 1);

        }
    } /* end of infinite for loop */

    DPRINTF("All memory is saved\n");

    {
        struct {
            int minustwo;
            int max_vcpu_id;
            uint64_t vcpumap;
        } chunk = { -2, info.max_vcpu_id };

        if ( info.max_vcpu_id >= 64 )
        {
            ERROR("Too many VCPUS in guest!");
            goto out;
        }

        for ( i = 1; i <= info.max_vcpu_id; i++ )
        {
            xc_vcpuinfo_t vinfo;
            if ( (xc_vcpu_getinfo(xc_handle, dom, i, &vinfo) == 0) &&
                 vinfo.online )
                vcpumap |= 1ULL << i;
        }

        chunk.vcpumap = vcpumap;
        if ( write_exact(io_fd, &chunk, sizeof(chunk)) )
        {
            PERROR("Error when writing to state file");
            goto out;
        }
    }

    if ( hvm )
    {
        struct {
            int id;
            uint32_t pad;
            uint64_t data;
        } chunk = { 0, };

        chunk.id = -3;
        xc_get_hvm_param(xc_handle, dom, HVM_PARAM_IDENT_PT,
                         (unsigned long *)&chunk.data);

        if ( (chunk.data != 0) &&
             write_exact(io_fd, &chunk, sizeof(chunk)) )
        {
            PERROR("Error when writing the ident_pt for EPT guest");
            goto out;
        }

        chunk.id = -4;
        xc_get_hvm_param(xc_handle, dom, HVM_PARAM_VM86_TSS,
                         (unsigned long *)&chunk.data);

        if ( (chunk.data != 0) &&
             write_exact(io_fd, &chunk, sizeof(chunk)) )
        {
            PERROR("Error when writing the vm86 TSS for guest");
            goto out;
        }
    }

    /* Zero terminate */
    i = 0;
    if ( write_exact(io_fd, &i, sizeof(int)) )
    {
        PERROR("Error when writing to state file (6')");
        goto out;
    }

    if ( hvm )
    {
        uint32_t rec_size;

        /* Save magic-page locations. */
        memset(magic_pfns, 0, sizeof(magic_pfns));
        xc_get_hvm_param(xc_handle, dom, HVM_PARAM_IOREQ_PFN,
                         (unsigned long *)&magic_pfns[0]);
        xc_get_hvm_param(xc_handle, dom, HVM_PARAM_BUFIOREQ_PFN,
                         (unsigned long *)&magic_pfns[1]);
        xc_get_hvm_param(xc_handle, dom, HVM_PARAM_STORE_PFN,
                         (unsigned long *)&magic_pfns[2]);
        if ( write_exact(io_fd, magic_pfns, sizeof(magic_pfns)) )
        {
            PERROR("Error when writing to state file (7)");
            goto out;
        }

        /* Get HVM context from Xen and save it too */
        if ( (rec_size = xc_domain_hvm_getcontext(xc_handle, dom, hvm_buf,
                                                  hvm_buf_size)) == -1 )
        {
            ERROR("HVM:Could not get hvm buffer");
            goto out;
        }

        if ( write_exact(io_fd, &rec_size, sizeof(uint32_t)) )
        {
            PERROR("error write hvm buffer size");
            goto out;
        }

        if ( write_exact(io_fd, hvm_buf, rec_size) )
        {
            PERROR("write HVM info failed!\n");
            goto out;
        }

        /* HVM guests are done now */
        rc = 0;
        goto out;
    }

    /* PV guests only from now on */

    /* Send through a list of all the PFNs that were not in map at the close */
    {
        unsigned int i,j;
        unsigned long pfntab[1024];

        for ( i = 0, j = 0; i < p2m_size; i++ )
        {
            if ( !is_mapped(pfn_to_mfn(i)) )
                j++;
        }

        if ( write_exact(io_fd, &j, sizeof(unsigned int)) )
        {
            PERROR("Error when writing to state file (6a)");
            goto out;
        }

        for ( i = 0, j = 0; i < p2m_size; )
        {
            if ( !is_mapped(pfn_to_mfn(i)) )
                pfntab[j++] = i;

            i++;
            if ( (j == 1024) || (i == p2m_size) )
            {
                if ( write_exact(io_fd, &pfntab, sizeof(unsigned long)*j) )
                {
                    PERROR("Error when writing to state file (6b)");
                    goto out;
                }
                j = 0;
            }
        }
    }

    if ( xc_vcpu_getcontext(xc_handle, dom, 0, &ctxt) )
    {
        ERROR("Could not get vcpu context");
        goto out;
    }

    /* Canonicalise the suspend-record frame number. */
    mfn = GET_FIELD(&ctxt, user_regs.edx);
    if ( !MFN_IS_IN_PSEUDOPHYS_MAP(mfn) )
    {
        ERROR("Suspend record is not in range of pseudophys map");
        goto out;
    }
    SET_FIELD(&ctxt, user_regs.edx, mfn_to_pfn(mfn));

    for ( i = 0; i <= info.max_vcpu_id; i++ )
    {
        if ( !(vcpumap & (1ULL << i)) )
            continue;

        if ( (i != 0) && xc_vcpu_getcontext(xc_handle, dom, i, &ctxt) )
        {
            ERROR("No context for VCPU%d", i);
            goto out;
        }

        /* Canonicalise each GDT frame number. */
        for ( j = 0; (512*j) < GET_FIELD(&ctxt, gdt_ents); j++ )
        {
            mfn = GET_FIELD(&ctxt, gdt_frames[j]);
            if ( !MFN_IS_IN_PSEUDOPHYS_MAP(mfn) )
            {
                ERROR("GDT frame is not in range of pseudophys map");
                goto out;
            }
            SET_FIELD(&ctxt, gdt_frames[j], mfn_to_pfn(mfn));
        }

        /* Canonicalise the page table base pointer. */
        if ( !MFN_IS_IN_PSEUDOPHYS_MAP(UNFOLD_CR3(
                                           GET_FIELD(&ctxt, ctrlreg[3]))) )
        {
            ERROR("PT base is not in range of pseudophys map");
            goto out;
        }
        SET_FIELD(&ctxt, ctrlreg[3],
            FOLD_CR3(mfn_to_pfn(UNFOLD_CR3(GET_FIELD(&ctxt, ctrlreg[3])))));

        /* Guest pagetable (x86/64) stored in otherwise-unused CR1. */
        if ( (pt_levels == 4) && ctxt.x64.ctrlreg[1] )
        {
            if ( !MFN_IS_IN_PSEUDOPHYS_MAP(UNFOLD_CR3(ctxt.x64.ctrlreg[1])) )
            {
                ERROR("PT base is not in range of pseudophys map");
                goto out;
            }
            /* Least-significant bit means 'valid PFN'. */
            ctxt.x64.ctrlreg[1] = 1 |
                FOLD_CR3(mfn_to_pfn(UNFOLD_CR3(ctxt.x64.ctrlreg[1])));
        }

        if ( write_exact(io_fd, &ctxt, ((guest_width==8)
                                        ? sizeof(ctxt.x64)
                                        : sizeof(ctxt.x32))) )
        {
            PERROR("Error when writing to state file (1)");
            goto out;
        }

        domctl.cmd = XEN_DOMCTL_get_ext_vcpucontext;
        domctl.domain = dom;
        domctl.u.ext_vcpucontext.vcpu = i;
        if ( xc_domctl(xc_handle, &domctl) < 0 )
        {
            ERROR("No extended context for VCPU%d", i);
            goto out;
        }
        if ( write_exact(io_fd, &domctl.u.ext_vcpucontext, 128) )
        {
            PERROR("Error when writing to state file (2)");
            goto out;
        }
    }

    /*
     * Reset the MFN to be a known-invalid value. See map_frame_list_list().
     */
    memcpy(page, live_shinfo, PAGE_SIZE);
    SET_FIELD(((shared_info_any_t *)page),
              arch.pfn_to_mfn_frame_list_list, 0);
    if ( write_exact(io_fd, page, PAGE_SIZE) )
    {
        PERROR("Error when writing to state file (1)");
        goto out;
    }

    /* Success! */
    rc = 0;

 out:

    if ( live )
    {
        if ( xc_shadow_control(xc_handle, dom,
                               XEN_DOMCTL_SHADOW_OP_OFF,
                               NULL, 0, NULL, 0, NULL) < 0 )
            DPRINTF("Warning - couldn't disable shadow mode");
    }

    /* Flush last write and discard cache for file. */
    discard_file_cache(io_fd, 1 /* flush */);

    if ( live_shinfo )
        munmap(live_shinfo, PAGE_SIZE);

    if ( live_p2m )
        munmap(live_p2m, P2M_FLL_ENTRIES * PAGE_SIZE);

    if ( live_m2p )
        munmap(live_m2p, M2P_SIZE(max_mfn));

    free(pfn_type);
    free(pfn_batch);
    free(to_send);
    free(to_fix);
    free(to_skip);

    DPRINTF("Save exit rc=%d\n",rc);

    return !!rc;
}

/*
 * Local variables:
 * mode: C
 * c-set-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */

My work is based on Xen 3.4. You need to modify the attached file "xc_domain_save.c" to measure memory dirtying rate. Please see the details in the source code and my paper.  you should find the test results in /var/log/xen/xend.log,suppose I still remember
the location. The attached file TPCC.txt is an example.