RESEND Use superpages on restore/migrate

diff -r f9bb0bbea7c2 -r 57558d87761f tools/libxc/xc_domain_restore.c
@@ -48,6 +48,11 @@ struct restore_ctx {
 
 #define HEARTBEAT_MS 1000
 
+#define SUPERPAGE_PFN_SHIFT  9
+#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
+
+#define SUPER_PAGE_START(pfn)    (((pfn) & (SUPERPAGE_NR_PFNS-1)) == 0 )
+
 #ifndef __MINIOS__
 static ssize_t rdexact(xc_interface *xch, struct restore_ctx *ctx,
                        int fd, void* buf, size_t size)

@@ -882,9 +887,11 @@ static int pagebuf_get(xc_interface *xch
 static int apply_batch(xc_interface *xch, uint32_t dom, struct restore_ctx *ctx,
                        xen_pfn_t* region_mfn, unsigned long* pfn_type, int pae_extended_cr3,
                        unsigned int hvm, struct xc_mmu* mmu,
-                       pagebuf_t* pagebuf, int curbatch)
+                       pagebuf_t* pagebuf, int curbatch, int superpages)
 {
     int i, j, curpage, nr_mfns;
+    int k, scount;
+    unsigned long superpage_start=INVALID_P2M_ENTRY;
     /* used by debug verify code */
     unsigned long buf[PAGE_SIZE/sizeof(unsigned long)];
     /* Our mapping of the current region (batch) */

@@ -902,8 +909,8 @@ static int apply_batch(xc_interface *xch
     if (j > MAX_BATCH_SIZE)
         j = MAX_BATCH_SIZE;
 
-    /* First pass for this batch: work out how much memory to alloc */
-    nr_mfns = 0; 
+    /* First pass for this batch: work out how much memory to alloc, and detect superpages */
+    nr_mfns = scount = 0;
     for ( i = 0; i < j; i++ )
     {
         unsigned long pfn, pagetype;

@@ -914,19 +921,103 @@ static int apply_batch(xc_interface *xch
              (ctx->p2m[pfn] == INVALID_P2M_ENTRY) )
         {
             /* Have a live PFN which hasn't had an MFN allocated */
+
+            /* Logic if we're in the middle of detecting a candidate superpage */
+            if ( superpage_start != INVALID_P2M_ENTRY )
+            {
+                /* Is this the next expected continuation? */
+                if ( pfn == superpage_start + scount )
+                {
+                    if ( !superpages )
+                    {
+                        ERROR("Unexpexted codepath with no superpages");
+                        return -1;
+                    }
+
+                    scount++;
+
+                    /* If we've found a whole superpage, allocate it and update p2m */
+                    if ( scount  == SUPERPAGE_NR_PFNS )
+                    {
+                        unsigned long supermfn;
+
+
+                        supermfn=superpage_start;
+                        if ( xc_domain_populate_physmap_exact(xch, dom, 1,
+                                         SUPERPAGE_PFN_SHIFT, 0, &supermfn) != 0 )
+                        {
+                            DPRINTF("No 2M page available for pfn 0x%lx, fall back to 4K page.\n",
+                                    superpage_start);
+                            /* If we're falling back from a failed allocation, subtract one
+                             * from count, since the last page == pfn, which will behandled
+                             * anyway. */
+                            scount--;
+                            goto fallback;
+                        }
+
+                        DPRINTF("Mapping superpage (%d) pfn %lx, mfn %lx\n", scount, superpage_start, supermfn);
+                        for (k=0; k<scount; k++)
+                        {
+                            /* We just allocated a new mfn above; update p2m */
+                            ctx->p2m[superpage_start+k] = supermfn+k;
+                            ctx->nr_pfns++;
+                            /* region_map[] will be set below */
+                        }
+                        superpage_start=INVALID_P2M_ENTRY;
+                        scount=0;
+                    }
+                    continue;
+                }
+                
+            fallback:
+                DPRINTF("Falling back %d pages pfn %lx\n", scount, superpage_start);
+                for (k=0; k<scount; k++)
+                {
+                    ctx->p2m_batch[nr_mfns++] = superpage_start+k; 
+                    ctx->p2m[superpage_start+k]--;
+                }
+                superpage_start = INVALID_P2M_ENTRY;
+                scount=0;
+            }
+
+            /* Are we ready to start a new superpage candidate? */
+            if ( superpages && SUPER_PAGE_START(pfn) )
+            {
+                superpage_start=pfn;
+                scount++;
+                continue;
+            }
+            
+            /* Add the current pfn to pfn_batch */
             ctx->p2m_batch[nr_mfns++] = pfn; 
             ctx->p2m[pfn]--;
         }
-    } 
+    }
+
+    /* Clean up any partial superpage candidates */
+    if ( superpage_start != INVALID_P2M_ENTRY )
+    {
+        DPRINTF("Falling back %d pages pfn %lx\n", scount, superpage_start);
+        for (k=0; k<scount; k++)
+        {
+            ctx->p2m_batch[nr_mfns++] = superpage_start+k; 
+            ctx->p2m[superpage_start+k]--;
+        }
+        superpage_start = INVALID_P2M_ENTRY;
+    }
 
     /* Now allocate a bunch of mfns for this batch */
-    if ( nr_mfns &&
-         (xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0,
-                                            0, ctx->p2m_batch) != 0) )
-    { 
-        ERROR("Failed to allocate memory for batch.!\n"); 
-        errno = ENOMEM;
-        return -1;
+    if ( nr_mfns )
+    {
+        DPRINTF("Mapping order 0,  %d; first pfn %lx\n", nr_mfns, ctx->p2m_batch[0]);
+    
+        if(xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0,
+                                            0, ctx->p2m_batch) != 0) 
+        { 
+            ERROR("Failed to allocate memory for batch.!\n"); 
+            errno = ENOMEM;
+            return -1;
+        }
     }
 
     /* Second pass for this batch: update p2m[] and region_mfn[] */

@@ -977,7 +1068,8 @@ static int apply_batch(xc_interface *xch
 
         if (pfn_err[i])
         {
-            ERROR("unexpected PFN mapping failure");
+            ERROR("unexpected PFN mapping failure pfn %lx map_mfn %lx p2m_mfn %lx",
+                  pfn, region_mfn[i], ctx->p2m[pfn]);
             goto err_mapped;
         }
 

@@ -1148,9 +1240,6 @@ int xc_domain_restore(xc_interface *xch,
     /* For info only */
     ctx->nr_pfns = 0;
 
-    if ( superpages )
-        return 1;
-
     ctxt = xc_hypercall_buffer_alloc(xch, ctxt, sizeof(*ctxt));
 
     if ( ctxt == NULL )

@@ -1298,7 +1387,8 @@ int xc_domain_restore(xc_interface *xch,
             int brc;
 
             brc = apply_batch(xch, dom, ctx, region_mfn, pfn_type,
-                              pae_extended_cr3, hvm, mmu, &pagebuf, curbatch);
+                              pae_extended_cr3, hvm, mmu, &pagebuf, curbatch,
+                              superpages);
             if ( brc < 0 )
                 goto out;

diff -r 57558d87761f -r a629b41a8d1f tools/libxc/xc_domain_save.c
@@ -82,6 +82,11 @@ struct outbuf {
      ((mfn_to_pfn(_mfn) < (dinfo->p2m_size)) &&   \
       (pfn_to_mfn(mfn_to_pfn(_mfn)) == (_mfn))))
 
+#define SUPERPAGE_PFN_SHIFT  9
+#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
+
+#define SUPER_PAGE_START(pfn)    (((pfn) & (SUPERPAGE_NR_PFNS-1)) == 0 )
+
 /*
 ** During (live) save/migrate, we maintain a number of bitmaps to track
 ** which pages we have to send, to fixup, and to skip.

@@ -906,6 +911,7 @@ int xc_domain_save(xc_interface *xch, in
     int rc = 1, frc, i, j, last_iter = 0, iter = 0;
     int live  = (flags & XCFLAGS_LIVE);
     int debug = (flags & XCFLAGS_DEBUG);
+    int superpages = !!hvm;
     int race = 0, sent_last_iter, skip_this_iter = 0;
     unsigned int sent_this_iter = 0;
     int tmem_saved = 0;

@@ -1262,6 +1268,12 @@ int xc_domain_save(xc_interface *xch, in
                            (test_bit(n, to_fix)  && last_iter)) )
                         continue;
 
+                    /* First time through, try to keep superpages in the same batch */
+                    if ( superpages && iter == 1
+                         && SUPER_PAGE_START(n)
+                         && batch + SUPERPAGE_NR_PFNS > MAX_BATCH_SIZE )
+                        break;
+
                     /*
                     ** we get here if:
                     **  1. page is marked to_send & hasn't already been re-dirtied

diff -r a629b41a8d1f -r 2ee1b330f2d3 tools/libxc/xc_domain_restore.c
@@ -839,7 +839,8 @@ static int pagebuf_get_one(xc_interface 
 
     countpages = count;
     for (i = oldcount; i < buf->nr_pages; ++i)
-        if ((buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == XEN_DOMCTL_PFINFO_XTAB)
+        if ((buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == XEN_DOMCTL_PFINFO_XTAB
+            ||(buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == XEN_DOMCTL_PFINFO_XALLOC)
             --countpages;
 
     if (!countpages)

@@ -917,6 +918,7 @@ static int apply_batch(xc_interface *xch
         pfn      = pagebuf->pfn_types[i + curbatch] & ~XEN_DOMCTL_PFINFO_LTAB_MASK;
         pagetype = pagebuf->pfn_types[i + curbatch] &  XEN_DOMCTL_PFINFO_LTAB_MASK;
 
+        /* For allocation purposes, treat XEN_DOMCTL_PFINFO_XALLOC as a normal page */
         if ( (pagetype != XEN_DOMCTL_PFINFO_XTAB) && 
              (ctx->p2m[pfn] == INVALID_P2M_ENTRY) )
         {

@@ -1028,21 +1030,21 @@ static int apply_batch(xc_interface *xch
         pfn      = pagebuf->pfn_types[i + curbatch] & ~XEN_DOMCTL_PFINFO_LTAB_MASK;
         pagetype = pagebuf->pfn_types[i + curbatch] &  XEN_DOMCTL_PFINFO_LTAB_MASK;
 
-        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB )
+        if ( pagetype != XEN_DOMCTL_PFINFO_XTAB
+             && ctx->p2m[pfn] == (INVALID_P2M_ENTRY-1) )
+        {
+            /* We just allocated a new mfn above; update p2m */
+            ctx->p2m[pfn] = ctx->p2m_batch[nr_mfns++]; 
+            ctx->nr_pfns++; 
+        }
+
+        /* setup region_mfn[] for batch map, if necessary.
+         * For HVM guests, this interface takes PFNs, not MFNs */
+        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB
+             || pagetype == XEN_DOMCTL_PFINFO_XALLOC )
             region_mfn[i] = ~0UL; /* map will fail but we don't care */
-        else 
-        {
-            if ( ctx->p2m[pfn] == (INVALID_P2M_ENTRY-1) )
-            {
-                /* We just allocated a new mfn above; update p2m */
-                ctx->p2m[pfn] = ctx->p2m_batch[nr_mfns++]; 
-                ctx->nr_pfns++; 
-            }
-
-            /* setup region_mfn[] for batch map.
-             * For HVM guests, this interface takes PFNs, not MFNs */
+        else
             region_mfn[i] = hvm ? pfn : ctx->p2m[pfn]; 
-        }
     }
 
     /* Map relevant mfns */

@@ -1062,8 +1064,9 @@ static int apply_batch(xc_interface *xch
         pfn      = pagebuf->pfn_types[i + curbatch] & ~XEN_DOMCTL_PFINFO_LTAB_MASK;
         pagetype = pagebuf->pfn_types[i + curbatch] &  XEN_DOMCTL_PFINFO_LTAB_MASK;
 
-        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB )
-            /* a bogus/unmapped page: skip it */
+        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB 
+             || pagetype == XEN_DOMCTL_PFINFO_XALLOC)
+            /* a bogus/unmapped/allocate-only page: skip it */
             continue;
 
         if (pfn_err[i])

diff -r a629b41a8d1f -r 2ee1b330f2d3 tools/libxc/xc_domain_save.c
@@ -1258,13 +1258,15 @@ int xc_domain_save(xc_interface *xch, in
                 }
                 else
                 {
-                    if ( !last_iter &&
+                    int dont_skip = (last_iter || (superpages && iter==1));
+
+                    if ( !dont_skip &&
                          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_send) && dont_skip) ||
                            (test_bit(n, to_fix)  && last_iter)) )
                         continue;
 

@@ -1277,7 +1279,7 @@ int xc_domain_save(xc_interface *xch, in
                     /*
                     ** we get here if:
                     **  1. page is marked to_send & hasn't already been re-dirtied
-                    **  2. (ignore to_skip in last iteration)
+                    **  2. (ignore to_skip in first and last iterations)
                     **  3. add in pages that still need fixup (net bufs)
                     */
 

@@ -1301,7 +1303,7 @@ int xc_domain_save(xc_interface *xch, in
                         set_bit(n, to_fix);
                         continue;
                     }
-
+                    
                     if ( last_iter &&
                          test_bit(n, to_fix) &&
                          !test_bit(n, to_send) )

@@ -1346,6 +1348,7 @@ int xc_domain_save(xc_interface *xch, in
                 {
                     if ( pfn_type[j] == XEN_DOMCTL_PFINFO_XTAB )
                         continue;
+
                     DPRINTF("map fail: page %i mfn %08lx err %d\n",
                             j, gmfn, pfn_err[j]);
                     pfn_type[j] = XEN_DOMCTL_PFINFO_XTAB;

@@ -1358,6 +1361,9 @@ int xc_domain_save(xc_interface *xch, in
                     continue;
                 }
 
+                if ( superpages && iter==1 && test_bit(gmfn, to_skip))
+                    pfn_type[j] = XEN_DOMCTL_PFINFO_XALLOC;
+
                 /* canonicalise mfn->pfn */
                 pfn_type[j] |= pfn_batch[j];
                 ++run;

@@ -1432,8 +1438,9 @@ int xc_domain_save(xc_interface *xch, in
                     }
                 }
 
-                /* skip pages that aren't present */
-                if ( pagetype == XEN_DOMCTL_PFINFO_XTAB )
+                /* skip pages that aren't present or are alloc-only */
+                if ( pagetype == XEN_DOMCTL_PFINFO_XTAB
+                    || pagetype == XEN_DOMCTL_PFINFO_XALLOC )
                     continue;
 
                 pagetype &= XEN_DOMCTL_PFINFO_LTABTYPE_MASK;

diff -r a629b41a8d1f -r 2ee1b330f2d3 xen/include/public/domctl.h
@@ -133,6 +133,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_getme
 #define XEN_DOMCTL_PFINFO_LTABTYPE_MASK (0x7U<<28)
 #define XEN_DOMCTL_PFINFO_LPINTAB (0x1U<<31)
 #define XEN_DOMCTL_PFINFO_XTAB    (0xfU<<28) /* invalid page */
+#define XEN_DOMCTL_PFINFO_XALLOC  (0xeU<<28) /* allocate-only page */
 #define XEN_DOMCTL_PFINFO_PAGEDTAB (0x8U<<28)
 #define XEN_DOMCTL_PFINFO_LTAB_MASK (0xfU<<28)

diff -r 2ee1b330f2d3 -r 454501a50504 tools/libxl/libxl_dom.c
@@ -316,7 +316,7 @@ int libxl__domain_restore_common(libxl__
     rc = xc_domain_restore(ctx->xch, fd, domid,
                              state->store_port, &state->store_mfn,
                              state->console_port, &state->console_mfn,
-                             info->hvm, info->u.hvm.pae, 0);
+                             info->hvm, info->u.hvm.pae, !!info->hvm);
     if ( rc ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "restoring domain");
         return ERROR_FAIL;

diff -r 2ee1b330f2d3 -r 454501a50504 tools/xcutils/xc_restore.c
@@ -43,7 +43,7 @@ main(int argc, char **argv)
     if ( argc == 9 )
 	    superpages = atoi(argv[8]);
     else
-	    superpages = 0;
+	    superpages = !!hvm;
 
     ret = xc_domain_restore(xch, io_fd, domid, store_evtchn, &store_mfn,
                             console_evtchn, &console_mfn, hvm, pae, superpages);