[Qemu-devel] [PATCH 06/15] postcopy: Record largest page size

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <address@hidden>

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

Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
 exec.c                        | 13 +++++++++++++
 include/exec/cpu-common.h     |  1 +
 include/migration/migration.h |  1 +
 migration/migration.c         |  1 +
 4 files changed, 16 insertions(+)

diff --git a/exec.c b/exec.c
index 8d4bb0e..69331d0 100644
--- a/exec.c
+++ b/exec.c
@@ -1485,6 +1485,19 @@ 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)) {
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index bd15853..0e67727 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -64,6 +64,7 @@ void qemu_ram_set_idstr(RAMBlock *block, const char *name, 
DeviceState *dev);
 void qemu_ram_unset_idstr(RAMBlock *block);
 const char *qemu_ram_get_idstr(RAMBlock *rb);
 size_t qemu_ram_pagesize(RAMBlock *block);
+size_t qemu_ram_pagesize_largest(void);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write);
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 0188bcf..7b311dd 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -89,6 +89,7 @@ struct MigrationIncomingState {
      */
     QemuEvent main_thread_load_event;
 
+    size_t         largest_page_size;
     bool           have_fault_thread;
     QemuThread     fault_thread;
     QemuSemaphore  fault_thread_sem;
diff --git a/migration/migration.c b/migration/migration.c
index f498ab8..d8dafde 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -387,6 +387,7 @@ static void process_incoming_migration_co(void *opaque)
     int ret;
 
     mis = migration_incoming_state_new(f);
+    mis->largest_page_size = qemu_ram_pagesize_largest();
     postcopy_state_set(POSTCOPY_INCOMING_NONE);
     migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
                       MIGRATION_STATUS_ACTIVE);
-- 
2.9.3