migration: Support QLIST migration

Support QLIST migration using the same principle as QTAILQ:
94869d5c52 ("migration: migrate QTAILQ").

The VMSTATE_QLIST_V macro has the same proto as VMSTATE_QTAILQ_V.
The change mainly resides in QLIST RAW macros: QLIST_RAW_INSERT_HEAD
and QLIST_RAW_REVERSE.

Tests also are provided.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

2 files changed, 75 insertions, 0 deletions

diff --git a/migration/trace-events b/migration/trace-events
index 2f9129e213..4ab0a503d2 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -76,6 +76,11 @@ get_gtree_end(const char *field_name, const char *key_vmsd_name, const char *val
 put_gtree(const char *field_name, const char *key_vmsd_name, const char *val_vmsd_name, uint32_t nnodes) "%s(%s/%s) nnodes=%d"
 put_gtree_end(const char *field_name, const char *key_vmsd_name, const char *val_vmsd_name, int ret) "%s(%s/%s) %d"
 
+get_qlist(const char *field_name, const char *vmsd_name, int version_id) "%s(%s v%d)"
+get_qlist_end(const char *field_name, const char *vmsd_name) "%s(%s)"
+put_qlist(const char *field_name, const char *vmsd_name, int version_id) "%s(%s v%d)"
+put_qlist_end(const char *field_name, const char *vmsd_name) "%s(%s)"
+
 # qemu-file.c
 qemu_file_fclose(void) ""
 
diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
index 7236cf92bc..1eee36773a 100644
--- a/migration/vmstate-types.c
+++ b/migration/vmstate-types.c
@@ -843,3 +843,73 @@ const VMStateInfo vmstate_info_gtree = {
     .get  = get_gtree,
     .put  = put_gtree,
 };
+
+static int put_qlist(QEMUFile *f, void *pv, size_t unused_size,
+                     const VMStateField *field, QJSON *vmdesc)
+{
+    const VMStateDescription *vmsd = field->vmsd;
+    /* offset of the QTAILQ entry in a QTAILQ element*/
+    size_t entry_offset = field->start;
+    void *elm;
+    int ret;
+
+    trace_put_qlist(field->name, vmsd->name, vmsd->version_id);
+    QLIST_RAW_FOREACH(elm, pv, entry_offset) {
+        qemu_put_byte(f, true);
+        ret = vmstate_save_state(f, vmsd, elm, vmdesc);
+        if (ret) {
+            error_report("%s: failed to save %s (%d)", field->name,
+                         vmsd->name, ret);
+            return ret;
+        }
+    }
+    qemu_put_byte(f, false);
+    trace_put_qlist_end(field->name, vmsd->name);
+
+    return 0;
+}
+
+static int get_qlist(QEMUFile *f, void *pv, size_t unused_size,
+                     const VMStateField *field)
+{
+    int ret = 0;
+    const VMStateDescription *vmsd = field->vmsd;
+    /* size of a QLIST element */
+    size_t size = field->size;
+    /* offset of the QLIST entry in a QLIST element */
+    size_t entry_offset = field->start;
+    int version_id = field->version_id;
+    void *elm;
+
+    trace_get_qlist(field->name, vmsd->name, vmsd->version_id);
+    if (version_id > vmsd->version_id) {
+        error_report("%s %s",  vmsd->name, "too new");
+        return -EINVAL;
+    }
+    if (version_id < vmsd->minimum_version_id) {
+        error_report("%s %s",  vmsd->name, "too old");
+        return -EINVAL;
+    }
+
+    while (qemu_get_byte(f)) {
+        elm = g_malloc(size);
+        ret = vmstate_load_state(f, vmsd, elm, version_id);
+        if (ret) {
+            error_report("%s: failed to load %s (%d)", field->name,
+                         vmsd->name, ret);
+            g_free(elm);
+            return ret;
+        }
+        QLIST_RAW_INSERT_HEAD(pv, elm, entry_offset);
+    }
+    QLIST_RAW_REVERSE(pv, elm, entry_offset);
+    trace_get_qlist_end(field->name, vmsd->name);
+
+    return ret;
+}
+
+const VMStateInfo vmstate_info_qlist = {
+    .name = "qlist",
+    .get  = get_qlist,
+    .put  = put_qlist,
+};