migration/postcopy: count target page number to decide the place_needed

In postcopy, it requires to place whole host page instead of target
page.

Currently, it relies on the page offset to decide whether this is the
last target page. We also can count the target page number during the
iteration. When the number of target page equals
(host page size / target page size), this means it is the last target
page in the host page.

This is a preparation for non-ordered target page transmission.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index c13b44b4d9bebbf1bee49256fb4b3c045ad45693..8ebaea255ee8ed33bef838645b72b2bda15c440a 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -4052,6 +4052,7 @@ static int ram_load_postcopy(QEMUFile *f)
     void *postcopy_host_page = mis->postcopy_tmp_page;
     void *last_host = NULL;
     bool all_zero = false;
+    int target_pages = 0;
 
     while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
         ram_addr_t addr;
@@ -4086,6 +4087,7 @@ static int ram_load_postcopy(QEMUFile *f)
                 ret = -EINVAL;
                 break;
             }
+            target_pages++;
             matches_target_page_size = block->page_size == TARGET_PAGE_SIZE;
             /*
              * Postcopy requires that we place whole host pages atomically;
@@ -4117,8 +4119,10 @@ static int ram_load_postcopy(QEMUFile *f)
              * If it's the last part of a host page then we place the host
              * page
              */
-            place_needed = (((uintptr_t)host + TARGET_PAGE_SIZE) &
-                                     (block->page_size - 1)) == 0;
+            if (target_pages == (block->page_size / TARGET_PAGE_SIZE)) {
+                place_needed = true;
+                target_pages = 0;
+            }
             place_source = postcopy_host_page;
         }
         last_host = host;