[Xen-changelog] Better handle page type info becoming incoherent during live migrate.

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User smh22@xxxxxxxxxxxxxxxxxxxx
# Node ID 72a1421dcf1b247d10485be8f72112c7703e7667
# Parent  bc1bfdb35f29504105f231f41cbcfe997c53e475
Better handle page type info becoming incoherent during live migrate. 
 
Signed-off-by: Steven Hand <steven@xxxxxxxxxxxxx>

diff -r bc1bfdb35f29 -r 72a1421dcf1b tools/libxc/xc_linux_save.c
--- a/tools/libxc/xc_linux_save.c       Tue Nov 22 16:00:56 2005
+++ b/tools/libxc/xc_linux_save.c       Tue Nov 22 16:50:41 2005
@@ -470,10 +470,9 @@
         if (pte & _PAGE_PRESENT) {
             
             mfn = (pte >> PAGE_SHIFT) & 0xfffffff;      
-            pfn = live_m2p[mfn];
-            
             if (!MFN_IS_IN_PSEUDOPHYS_MAP(mfn)) {
-                /* I don't think this should ever happen */
+                /* This will happen if the type info is stale which 
+                   is quite feasible under live migration */
                 DPRINTF("FNI: [%08lx,%d] pte=%llx,"
                         " mfn=%08lx, pfn=%08lx [mfn]=%08lx\n",
                         type, i, (unsigned long long)pte, mfn, 
@@ -482,7 +481,10 @@
                         live_p2m[live_m2p[mfn]] : 0xdeadbeaf);
                 
                 pfn = 0; /* be suspicious */
-            }
+            } else 
+                pfn = live_m2p[mfn];
+            
+
             
             pte &= 0xffffff0000000fffULL;
             pte |= (uint64_t)pfn << PAGE_SHIFT;
@@ -1031,7 +1033,7 @@
 
         if (last_iter && debug){
             int minusone = -1;
-            memset( to_send, 0xff, (max_pfn+8)/8 );
+            memset(to_send, 0xff, BITMAP_SIZE); 
             debug = 0;
             fprintf(stderr, "Entering debug resend-all mode\n");
     

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