[Qemu-devel] [PATCH 1/2] vmstate: Add helper to enable GHashTable migration

[Alexey Kardashevskiy]

This adds a VMSTATE_HASH_V macro. This implements put/get callbacks for it.
This implements a qemu_hash_init() wrapper to save key/value sizes.

Signed-off-by: Alexey Kardashevskiy <address@hidden>
---
 include/migration/vmstate.h | 10 +++++++++
 include/qemu-common.h       | 13 +++++++++++
 vmstate.c                   | 54 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 7e45048..6af599d 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -166,6 +166,7 @@ extern const VMStateInfo vmstate_info_timer;
 extern const VMStateInfo vmstate_info_buffer;
 extern const VMStateInfo vmstate_info_unused_buffer;
 extern const VMStateInfo vmstate_info_bitmap;
+static const VMStateInfo vmstate_info_hash;
 
 #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0)
 #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0)
@@ -740,6 +741,15 @@ extern const VMStateInfo vmstate_info_bitmap;
 #define VMSTATE_BUFFER_UNSAFE(_field, _state, _version, _size)        \
     VMSTATE_BUFFER_UNSAFE_INFO(_field, _state, _version, vmstate_info_buffer, 
_size)
 
+#define VMSTATE_HASH_V(_field, _state, _version) {                      \
+    .name       = (stringify(_field)),                                  \
+    .version_id = (_version),                                           \
+    .size       = sizeof(qemu_hash),                                    \
+    .info       = &vmstate_info_hash,                                   \
+    .flags      = VMS_SINGLE,                                           \
+    .offset     = vmstate_offset_value(_state, _field, qemu_hash),      \
+}
+
 #define VMSTATE_UNUSED_V(_v, _size)                                   \
     VMSTATE_UNUSED_BUFFER(NULL, _v, _size)
 
diff --git a/include/qemu-common.h b/include/qemu-common.h
index 3f3fd60..ee973e7 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -462,4 +462,17 @@ int parse_debug_env(const char *name, int max, int 
initial);
 
 const char *qemu_ether_ntoa(const MACAddr *mac);
 
+typedef struct qemu_hash {
+    GHashTable *hash;
+    int key_size;
+    int value_size;
+} qemu_hash;
+
+static inline void qemu_hash_init(qemu_hash *h, int key_size, int value_size)
+{
+    h->key_size = key_size;
+    h->value_size = value_size;
+    h->hash = g_hash_table_new_full(g_int_hash, g_int_equal, g_free, g_free);
+}
+
 #endif
diff --git a/vmstate.c b/vmstate.c
index b5882fa..2148e73 100644
--- a/vmstate.c
+++ b/vmstate.c
@@ -667,3 +667,57 @@ const VMStateInfo vmstate_info_bitmap = {
     .get = get_bitmap,
     .put = put_bitmap,
 };
+
+/* Save restore for qemu_hash which is a wrapper over GHashTable */
+static int get_hash(QEMUFile *f, void *pv, size_t size)
+{
+    qemu_hash *h = pv;
+    uint32_t num = g_hash_table_size(h->hash);
+    gpointer key, value;
+
+    num = qemu_get_be32(f);
+
+    for ( ; num; --num) {
+        int i;
+
+        key = g_malloc0(h->key_size);
+        for (i = 0; i < h->key_size; ++i) {
+            ((uint8_t *)key)[i] = qemu_get_byte(f);
+        }
+        value = g_malloc0(h->value_size);
+        for (i = 0; i < h->value_size; ++i) {
+            ((uint8_t *)value)[i] = qemu_get_byte(f);
+        }
+        g_hash_table_insert(h->hash, key, value);
+    }
+
+    return 0;
+}
+
+static void put_hash(QEMUFile *f, void *pv, size_t size)
+{
+    qemu_hash *h = pv;
+    uint32_t num = g_hash_table_size(h->hash);
+    GHashTableIter iter;
+    gpointer key, value;
+
+    qemu_put_be32(f, num);
+
+    g_hash_table_iter_init(&iter, h->hash);
+    while (g_hash_table_iter_next (&iter, &key, &value)) {
+        int i;
+
+        for (i = 0; i < h->key_size; ++i) {
+            qemu_put_byte(f, ((uint8_t *)key)[i]);
+        }
+        for (i = 0; i < h->value_size; ++i) {
+            qemu_put_byte(f, ((uint8_t *)value)[i]);
+        }
+    }
+}
+
+static const VMStateInfo vmstate_info_hash = {
+    .name = "qemu-hash-desc",
+    .get  = get_hash,
+    .put  = put_hash,
+};
-- 
1.9.rc0