postcopy: Record largest page size

Record the largest page size in use; we'll need it soon for allocating
temporary buffers.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-7-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index 24cdf64226..785d20f648 100644
--- a/exec.c
+++ b/exec.c
@@ -1524,6 +1524,19 @@ size_t qemu_ram_pagesize(RAMBlock *rb)
     return rb->page_size;
 }
 
+/* Returns the largest size of page in use */
+size_t qemu_ram_pagesize_largest(void)
+{
+    RAMBlock *block;
+    size_t largest = 0;
+
+    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+        largest = MAX(largest, qemu_ram_pagesize(block));
+    }
+
+    return largest;
+}
+
 static int memory_try_enable_merging(void *addr, size_t len)
 {
     if (!machine_mem_merge(current_machine)) {