Imported Upstream version 1.2.0upstream/1.2.0

20 files changed, 2292 insertions, 0 deletions

diff --git a/qapi/Makefile.objs b/qapi/Makefile.objs
new file mode 100644
index 000000000..5f5846e76
--- /dev/null
+++ b/qapi/Makefile.objs
@@ -0,0 +1,3 @@
+qapi-obj-y = qapi-visit-core.o qapi-dealloc-visitor.o qmp-input-visitor.o
+qapi-obj-y += qmp-output-visitor.o qmp-registry.o qmp-dispatch.o
+qapi-obj-y += string-input-visitor.o string-output-visitor.o opts-visitor.o
diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
new file mode 100644
index 000000000..e048b6c86
--- /dev/null
+++ b/qapi/opts-visitor.c
@@ -0,0 +1,427 @@
+/*
+ * Options Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Laszlo Ersek <lersek@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "opts-visitor.h"
+#include "qemu-queue.h"
+#include "qemu-option-internal.h"
+#include "qapi-visit-impl.h"
+
+
+struct OptsVisitor
+{
+    Visitor visitor;
+
+    /* Ownership remains with opts_visitor_new()'s caller. */
+    const QemuOpts *opts_root;
+
+    unsigned depth;
+
+    /* Non-null iff depth is positive. Each key is a QemuOpt name. Each value
+     * is a non-empty GQueue, enumerating all QemuOpt occurrences with that
+     * name. */
+    GHashTable *unprocessed_opts;
+
+    /* The list currently being traversed with opts_start_list() /
+     * opts_next_list(). The list must have a struct element type in the
+     * schema, with a single mandatory scalar member. */
+    GQueue *repeated_opts;
+    bool repeated_opts_first;
+
+    /* If "opts_root->id" is set, reinstantiate it as a fake QemuOpt for
+     * uniformity. Only its "name" and "str" fields are set. "fake_id_opt" does
+     * not survive or escape the OptsVisitor object.
+     */
+    QemuOpt *fake_id_opt;
+};
+
+
+static void
+destroy_list(gpointer list)
+{
+  g_queue_free(list);
+}
+
+
+static void
+opts_visitor_insert(GHashTable *unprocessed_opts, const QemuOpt *opt)
+{
+    GQueue *list;
+
+    list = g_hash_table_lookup(unprocessed_opts, opt->name);
+    if (list == NULL) {
+        list = g_queue_new();
+
+        /* GHashTable will never try to free the keys -- we supply NULL as
+         * "key_destroy_func" in opts_start_struct(). Thus cast away key
+         * const-ness in order to suppress gcc's warning.
+         */
+        g_hash_table_insert(unprocessed_opts, (gpointer)opt->name, list);
+    }
+
+    /* Similarly, destroy_list() doesn't call g_queue_free_full(). */
+    g_queue_push_tail(list, (gpointer)opt);
+}
+
+
+static void
+opts_start_struct(Visitor *v, void **obj, const char *kind,
+                  const char *name, size_t size, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+
+    *obj = g_malloc0(size > 0 ? size : 1);
+    if (ov->depth++ > 0) {
+        return;
+    }
+
+    ov->unprocessed_opts = g_hash_table_new_full(&g_str_hash, &g_str_equal,
+                                                 NULL, &destroy_list);
+    QTAILQ_FOREACH(opt, &ov->opts_root->head, next) {
+        /* ensured by qemu-option.c::opts_do_parse() */
+        assert(strcmp(opt->name, "id") != 0);
+
+        opts_visitor_insert(ov->unprocessed_opts, opt);
+    }
+
+    if (ov->opts_root->id != NULL) {
+        ov->fake_id_opt = g_malloc0(sizeof *ov->fake_id_opt);
+
+        ov->fake_id_opt->name = "id";
+        ov->fake_id_opt->str = ov->opts_root->id;
+        opts_visitor_insert(ov->unprocessed_opts, ov->fake_id_opt);
+    }
+}
+
+
+static gboolean
+ghr_true(gpointer ign_key, gpointer ign_value, gpointer ign_user_data)
+{
+    return TRUE;
+}
+
+
+static void
+opts_end_struct(Visitor *v, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    GQueue *any;
+
+    if (--ov->depth > 0) {
+        return;
+    }
+
+    /* we should have processed all (distinct) QemuOpt instances */
+    any = g_hash_table_find(ov->unprocessed_opts, &ghr_true, NULL);
+    if (any) {
+        const QemuOpt *first;
+
+        first = g_queue_peek_head(any);
+        error_set(errp, QERR_INVALID_PARAMETER, first->name);
+    }
+    g_hash_table_destroy(ov->unprocessed_opts);
+    ov->unprocessed_opts = NULL;
+    g_free(ov->fake_id_opt);
+    ov->fake_id_opt = NULL;
+}
+
+
+static GQueue *
+lookup_distinct(const OptsVisitor *ov, const char *name, Error **errp)
+{
+    GQueue *list;
+
+    list = g_hash_table_lookup(ov->unprocessed_opts, name);
+    if (!list) {
+        error_set(errp, QERR_MISSING_PARAMETER, name);
+    }
+    return list;
+}
+
+
+static void
+opts_start_list(Visitor *v, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+
+    /* we can't traverse a list in a list */
+    assert(ov->repeated_opts == NULL);
+    ov->repeated_opts = lookup_distinct(ov, name, errp);
+    ov->repeated_opts_first = (ov->repeated_opts != NULL);
+}
+
+
+static GenericList *
+opts_next_list(Visitor *v, GenericList **list, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    GenericList **link;
+
+    if (ov->repeated_opts_first) {
+        ov->repeated_opts_first = false;
+        link = list;
+    } else {
+        const QemuOpt *opt;
+
+        opt = g_queue_pop_head(ov->repeated_opts);
+        if (g_queue_is_empty(ov->repeated_opts)) {
+            g_hash_table_remove(ov->unprocessed_opts, opt->name);
+            return NULL;
+        }
+        link = &(*list)->next;
+    }
+
+    *link = g_malloc0(sizeof **link);
+    return *link;
+}
+
+
+static void
+opts_end_list(Visitor *v, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+
+    ov->repeated_opts = NULL;
+}
+
+
+static const QemuOpt *
+lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
+{
+    if (ov->repeated_opts == NULL) {
+        GQueue *list;
+
+        /* the last occurrence of any QemuOpt takes effect when queried by name
+         */
+        list = lookup_distinct(ov, name, errp);
+        return list ? g_queue_peek_tail(list) : NULL;
+    }
+    return g_queue_peek_head(ov->repeated_opts);
+}
+
+
+static void
+processed(OptsVisitor *ov, const char *name)
+{
+    if (ov->repeated_opts == NULL) {
+        g_hash_table_remove(ov->unprocessed_opts, name);
+    }
+}
+
+
+static void
+opts_type_str(Visitor *v, char **obj, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+
+    opt = lookup_scalar(ov, name, errp);
+    if (!opt) {
+        return;
+    }
+    *obj = g_strdup(opt->str ? opt->str : "");
+    processed(ov, name);
+}
+
+
+/* mimics qemu-option.c::parse_option_bool() */
+static void
+opts_type_bool(Visitor *v, bool *obj, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+
+    opt = lookup_scalar(ov, name, errp);
+    if (!opt) {
+        return;
+    }
+
+    if (opt->str) {
+        if (strcmp(opt->str, "on") == 0 ||
+            strcmp(opt->str, "yes") == 0 ||
+            strcmp(opt->str, "y") == 0) {
+            *obj = true;
+        } else if (strcmp(opt->str, "off") == 0 ||
+            strcmp(opt->str, "no") == 0 ||
+            strcmp(opt->str, "n") == 0) {
+            *obj = false;
+        } else {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
+                "on|yes|y|off|no|n");
+            return;
+        }
+    } else {
+        *obj = true;
+    }
+
+    processed(ov, name);
+}
+
+
+static void
+opts_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+    const char *str;
+    long long val;
+    char *endptr;
+
+    opt = lookup_scalar(ov, name, errp);
+    if (!opt) {
+        return;
+    }
+    str = opt->str ? opt->str : "";
+
+    errno = 0;
+    val = strtoll(str, &endptr, 0);
+    if (*str != '\0' && *endptr == '\0' && errno == 0 && INT64_MIN <= val &&
+        val <= INT64_MAX) {
+        *obj = val;
+        processed(ov, name);
+        return;
+    }
+    error_set(errp, QERR_INVALID_PARAMETER_VALUE, opt->name, "an int64 value");
+}
+
+
+static void
+opts_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+    const char *str;
+
+    opt = lookup_scalar(ov, name, errp);
+    if (!opt) {
+        return;
+    }
+
+    str = opt->str;
+    if (str != NULL) {
+        while (isspace((unsigned char)*str)) {
+            ++str;
+        }
+
+        if (*str != '-' && *str != '\0') {
+            unsigned long long val;
+            char *endptr;
+
+            /* non-empty, non-negative subject sequence */
+            errno = 0;
+            val = strtoull(str, &endptr, 0);
+            if (*endptr == '\0' && errno == 0 && val <= UINT64_MAX) {
+                *obj = val;
+                processed(ov, name);
+                return;
+            }
+        }
+    }
+    error_set(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
+              "an uint64 value");
+}
+
+
+static void
+opts_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    const QemuOpt *opt;
+    int64_t val;
+    char *endptr;
+
+    opt = lookup_scalar(ov, name, errp);
+    if (!opt) {
+        return;
+    }
+
+    val = strtosz_suffix(opt->str ? opt->str : "", &endptr,
+                         STRTOSZ_DEFSUFFIX_B);
+    if (val != -1 && *endptr == '\0') {
+        *obj = val;
+        processed(ov, name);
+        return;
+    }
+    error_set(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
+              "a size value representible as a non-negative int64");
+}
+
+
+static void
+opts_start_optional(Visitor *v, bool *present, const char *name,
+                       Error **errp)
+{
+    OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+
+    /* we only support a single mandatory scalar field in a list node */
+    assert(ov->repeated_opts == NULL);
+    *present = (lookup_distinct(ov, name, NULL) != NULL);
+}
+
+
+OptsVisitor *
+opts_visitor_new(const QemuOpts *opts)
+{
+    OptsVisitor *ov;
+
+    ov = g_malloc0(sizeof *ov);
+
+    ov->visitor.start_struct = &opts_start_struct;
+    ov->visitor.end_struct   = &opts_end_struct;
+
+    ov->visitor.start_list = &opts_start_list;
+    ov->visitor.next_list  = &opts_next_list;
+    ov->visitor.end_list   = &opts_end_list;
+
+    /* input_type_enum() covers both "normal" enums and union discriminators.
+     * The union discriminator field is always generated as "type"; it should
+     * match the "type" QemuOpt child of any QemuOpts.
+     *
+     * input_type_enum() will remove the looked-up key from the
+     * "unprocessed_opts" hash even if the lookup fails, because the removal is
+     * done earlier in opts_type_str(). This should be harmless.
+     */
+    ov->visitor.type_enum = &input_type_enum;
+
+    ov->visitor.type_int    = &opts_type_int;
+    ov->visitor.type_uint64 = &opts_type_uint64;
+    ov->visitor.type_size   = &opts_type_size;
+    ov->visitor.type_bool   = &opts_type_bool;
+    ov->visitor.type_str    = &opts_type_str;
+
+    /* type_number() is not filled in, but this is not the first visitor to
+     * skip some mandatory methods... */
+
+    ov->visitor.start_optional = &opts_start_optional;
+
+    ov->opts_root = opts;
+
+    return ov;
+}
+
+
+void
+opts_visitor_cleanup(OptsVisitor *ov)
+{
+    if (ov->unprocessed_opts != NULL) {
+        g_hash_table_destroy(ov->unprocessed_opts);
+    }
+    g_free(ov->fake_id_opt);
+    g_free(ov);
+}
+
+
+Visitor *
+opts_get_visitor(OptsVisitor *ov)
+{
+    return &ov->visitor;
+}
diff --git a/qapi/opts-visitor.h b/qapi/opts-visitor.h
new file mode 100644
index 000000000..ea1a39557
--- /dev/null
+++ b/qapi/opts-visitor.h
@@ -0,0 +1,31 @@
+/*
+ * Options Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Laszlo Ersek <lersek@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef OPTS_VISITOR_H
+#define OPTS_VISITOR_H
+
+#include "qapi-visit-core.h"
+#include "qemu-option.h"
+
+typedef struct OptsVisitor OptsVisitor;
+
+/* Contrarily to qemu-option.c::parse_option_number(), OptsVisitor's "int"
+ * parser relies on strtoll() instead of strtoull(). Consequences:
+ * - string representations of negative numbers yield negative values,
+ * - values below INT64_MIN or LLONG_MIN are rejected,
+ * - values above INT64_MAX or LLONG_MAX are rejected.
+ */
+OptsVisitor *opts_visitor_new(const QemuOpts *opts);
+void opts_visitor_cleanup(OptsVisitor *nv);
+Visitor *opts_get_visitor(OptsVisitor *nv);
+
+#endif
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
new file mode 100644
index 000000000..a15452373
--- /dev/null
+++ b/qapi/qapi-dealloc-visitor.c
@@ -0,0 +1,171 @@
+/*
+ * Dealloc Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Michael Roth   <mdroth@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qapi-dealloc-visitor.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+
+typedef struct StackEntry
+{
+    void *value;
+    bool is_list_head;
+    QTAILQ_ENTRY(StackEntry) node;
+} StackEntry;
+
+struct QapiDeallocVisitor
+{
+    Visitor visitor;
+    QTAILQ_HEAD(, StackEntry) stack;
+    bool is_list_head;
+};
+
+static QapiDeallocVisitor *to_qov(Visitor *v)
+{
+    return container_of(v, QapiDeallocVisitor, visitor);
+}
+
+static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value)
+{
+    StackEntry *e = g_malloc0(sizeof(*e));
+
+    e->value = value;
+
+    /* see if we're just pushing a list head tracker */
+    if (value == NULL) {
+        e->is_list_head = true;
+    }
+    QTAILQ_INSERT_HEAD(&qov->stack, e, node);
+}
+
+static void *qapi_dealloc_pop(QapiDeallocVisitor *qov)
+{
+    StackEntry *e = QTAILQ_FIRST(&qov->stack);
+    QObject *value;
+    QTAILQ_REMOVE(&qov->stack, e, node);
+    value = e->value;
+    g_free(e);
+    return value;
+}
+
+static void qapi_dealloc_start_struct(Visitor *v, void **obj, const char *kind,
+                                      const char *name, size_t unused,
+                                      Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    qapi_dealloc_push(qov, obj);
+}
+
+static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    void **obj = qapi_dealloc_pop(qov);
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    qapi_dealloc_push(qov, NULL);
+}
+
+static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp,
+                                           Error **errp)
+{
+    GenericList *list = *listp;
+    QapiDeallocVisitor *qov = to_qov(v);
+    StackEntry *e = QTAILQ_FIRST(&qov->stack);
+
+    if (e && e->is_list_head) {
+        e->is_list_head = false;
+        return list;
+    }
+
+    if (list) {
+        list = list->next;
+        g_free(*listp);
+        return list;
+    }
+
+    return NULL;
+}
+
+static void qapi_dealloc_end_list(Visitor *v, Error **errp)
+{
+    QapiDeallocVisitor *qov = to_qov(v);
+    void *obj = qapi_dealloc_pop(qov);
+    assert(obj == NULL); /* should've been list head tracker with no payload */
+}
+
+static void qapi_dealloc_type_str(Visitor *v, char **obj, const char *name,
+                                  Error **errp)
+{
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qapi_dealloc_type_int(Visitor *v, int64_t *obj, const char *name,
+                                  Error **errp)
+{
+}
+
+static void qapi_dealloc_type_bool(Visitor *v, bool *obj, const char *name,
+                                   Error **errp)
+{
+}
+
+static void qapi_dealloc_type_number(Visitor *v, double *obj, const char *name,
+                                     Error **errp)
+{
+}
+
+static void qapi_dealloc_type_enum(Visitor *v, int *obj, const char *strings[],
+                                   const char *kind, const char *name,
+                                   Error **errp)
+{
+}
+
+Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
+{
+    g_free(v);
+}
+
+QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
+{
+    QapiDeallocVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.start_struct = qapi_dealloc_start_struct;
+    v->visitor.end_struct = qapi_dealloc_end_struct;
+    v->visitor.start_list = qapi_dealloc_start_list;
+    v->visitor.next_list = qapi_dealloc_next_list;
+    v->visitor.end_list = qapi_dealloc_end_list;
+    v->visitor.type_enum = qapi_dealloc_type_enum;
+    v->visitor.type_int = qapi_dealloc_type_int;
+    v->visitor.type_bool = qapi_dealloc_type_bool;
+    v->visitor.type_str = qapi_dealloc_type_str;
+    v->visitor.type_number = qapi_dealloc_type_number;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}
diff --git a/qapi/qapi-dealloc-visitor.h b/qapi/qapi-dealloc-visitor.h
new file mode 100644
index 000000000..5842bc79b
--- /dev/null
+++ b/qapi/qapi-dealloc-visitor.h
@@ -0,0 +1,26 @@
+/*
+ * Dealloc Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Michael Roth   <mdroth@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QAPI_DEALLOC_VISITOR_H
+#define QAPI_DEALLOC_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct QapiDeallocVisitor QapiDeallocVisitor;
+
+QapiDeallocVisitor *qapi_dealloc_visitor_new(void);
+void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *d);
+
+Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v);
+
+#endif
diff --git a/qapi/qapi-types-core.h b/qapi/qapi-types-core.h
new file mode 100644
index 000000000..f781fc3ab
--- /dev/null
+++ b/qapi/qapi-types-core.h
@@ -0,0 +1,21 @@
+/*
+ * Core Definitions for QAPI-generated Types
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QAPI_TYPES_CORE_H
+#define QAPI_TYPES_CORE_H
+
+#include "qemu-common.h"
+#include "error.h"
+#include "qerror.h"
+
+#endif
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
new file mode 100644
index 000000000..7a82b6376
--- /dev/null
+++ b/qapi/qapi-visit-core.c
@@ -0,0 +1,313 @@
+/*
+ * Core Definitions for QAPI Visitor Classes
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qapi/qapi-visit-core.h"
+#include "qapi/qapi-visit-impl.h"
+
+void visit_start_handle(Visitor *v, void **obj, const char *kind,
+                        const char *name, Error **errp)
+{
+    if (!error_is_set(errp) && v->start_handle) {
+        v->start_handle(v, obj, kind, name, errp);
+    }
+}
+
+void visit_end_handle(Visitor *v, Error **errp)
+{
+    if (!error_is_set(errp) && v->end_handle) {
+        v->end_handle(v, errp);
+    }
+}
+
+void visit_start_struct(Visitor *v, void **obj, const char *kind,
+                        const char *name, size_t size, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->start_struct(v, obj, kind, name, size, errp);
+    }
+}
+
+void visit_end_struct(Visitor *v, Error **errp)
+{
+    assert(!error_is_set(errp));
+    v->end_struct(v, errp);
+}
+
+void visit_start_list(Visitor *v, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->start_list(v, name, errp);
+    }
+}
+
+GenericList *visit_next_list(Visitor *v, GenericList **list, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        return v->next_list(v, list, errp);
+    }
+
+    return 0;
+}
+
+void visit_end_list(Visitor *v, Error **errp)
+{
+    assert(!error_is_set(errp));
+    v->end_list(v, errp);
+}
+
+void visit_start_optional(Visitor *v, bool *present, const char *name,
+                          Error **errp)
+{
+    if (!error_is_set(errp) && v->start_optional) {
+        v->start_optional(v, present, name, errp);
+    }
+}
+
+void visit_end_optional(Visitor *v, Error **errp)
+{
+    if (!error_is_set(errp) && v->end_optional) {
+        v->end_optional(v, errp);
+    }
+}
+
+void visit_type_enum(Visitor *v, int *obj, const char *strings[],
+                     const char *kind, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->type_enum(v, obj, strings, kind, name, errp);
+    }
+}
+
+void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->type_int(v, obj, name, errp);
+    }
+}
+
+void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_uint8) {
+            v->type_uint8(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < 0 || value > UINT8_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "uint8_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_uint16) {
+            v->type_uint16(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < 0 || value > UINT16_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "uint16_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_uint32) {
+            v->type_uint32(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < 0 || value > UINT32_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "uint32_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_uint64) {
+            v->type_uint64(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_int8) {
+            v->type_int8(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < INT8_MIN || value > INT8_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "int8_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_int16) {
+            v->type_int16(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < INT16_MIN || value > INT16_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "int16_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp)
+{
+    int64_t value;
+    if (!error_is_set(errp)) {
+        if (v->type_int32) {
+            v->type_int32(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            if (value < INT32_MIN || value > INT32_MAX) {
+                error_set(errp, QERR_INVALID_PARAMETER_VALUE, name ? name : "null",
+                          "int32_t");
+                return;
+            }
+            *obj = value;
+        }
+    }
+}
+
+void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        if (v->type_int64) {
+            v->type_int64(v, obj, name, errp);
+        } else {
+            v->type_int(v, obj, name, errp);
+        }
+    }
+}
+
+void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        (v->type_size ? v->type_size : v->type_uint64)(v, obj, name, errp);
+    }
+}
+
+void visit_type_bool(Visitor *v, bool *obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->type_bool(v, obj, name, errp);
+    }
+}
+
+void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->type_str(v, obj, name, errp);
+    }
+}
+
+void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp)
+{
+    if (!error_is_set(errp)) {
+        v->type_number(v, obj, name, errp);
+    }
+}
+
+void output_type_enum(Visitor *v, int *obj, const char *strings[],
+                      const char *kind, const char *name,
+                      Error **errp)
+{
+    int i = 0;
+    int value = *obj;
+    char *enum_str;
+
+    assert(strings);
+    while (strings[i++] != NULL);
+    if (value < 0 || value >= i - 1) {
+        error_set(errp, QERR_INVALID_PARAMETER, name ? name : "null");
+        return;
+    }
+
+    enum_str = (char *)strings[value];
+    visit_type_str(v, &enum_str, name, errp);
+}
+
+void input_type_enum(Visitor *v, int *obj, const char *strings[],
+                     const char *kind, const char *name,
+                     Error **errp)
+{
+    int64_t value = 0;
+    char *enum_str;
+
+    assert(strings);
+
+    visit_type_str(v, &enum_str, name, errp);
+    if (error_is_set(errp)) {
+        return;
+    }
+
+    while (strings[value] != NULL) {
+        if (strcmp(strings[value], enum_str) == 0) {
+            break;
+        }
+        value++;
+    }
+
+    if (strings[value] == NULL) {
+        error_set(errp, QERR_INVALID_PARAMETER, enum_str);
+        g_free(enum_str);
+        return;
+    }
+
+    g_free(enum_str);
+    *obj = value;
+}
diff --git a/qapi/qapi-visit-core.h b/qapi/qapi-visit-core.h
new file mode 100644
index 000000000..60acedac7
--- /dev/null
+++ b/qapi/qapi-visit-core.h
@@ -0,0 +1,95 @@
+/*
+ * Core Definitions for QAPI Visitor Classes
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+#ifndef QAPI_VISITOR_CORE_H
+#define QAPI_VISITOR_CORE_H
+
+#include "qapi/qapi-types-core.h"
+#include <stdlib.h>
+
+typedef struct GenericList
+{
+    void *value;
+    struct GenericList *next;
+} GenericList;
+
+typedef struct Visitor Visitor;
+
+struct Visitor
+{
+    /* Must be set */
+    void (*start_struct)(Visitor *v, void **obj, const char *kind,
+                         const char *name, size_t size, Error **errp);
+    void (*end_struct)(Visitor *v, Error **errp);
+
+    void (*start_list)(Visitor *v, const char *name, Error **errp);
+    GenericList *(*next_list)(Visitor *v, GenericList **list, Error **errp);
+    void (*end_list)(Visitor *v, Error **errp);
+
+    void (*type_enum)(Visitor *v, int *obj, const char *strings[],
+                      const char *kind, const char *name, Error **errp);
+
+    void (*type_int)(Visitor *v, int64_t *obj, const char *name, Error **errp);
+    void (*type_bool)(Visitor *v, bool *obj, const char *name, Error **errp);
+    void (*type_str)(Visitor *v, char **obj, const char *name, Error **errp);
+    void (*type_number)(Visitor *v, double *obj, const char *name,
+                        Error **errp);
+
+    /* May be NULL */
+    void (*start_optional)(Visitor *v, bool *present, const char *name,
+                           Error **errp);
+    void (*end_optional)(Visitor *v, Error **errp);
+
+    void (*start_handle)(Visitor *v, void **obj, const char *kind,
+                         const char *name, Error **errp);
+    void (*end_handle)(Visitor *v, Error **errp);
+    void (*type_uint8)(Visitor *v, uint8_t *obj, const char *name, Error **errp);
+    void (*type_uint16)(Visitor *v, uint16_t *obj, const char *name, Error **errp);
+    void (*type_uint32)(Visitor *v, uint32_t *obj, const char *name, Error **errp);
+    void (*type_uint64)(Visitor *v, uint64_t *obj, const char *name, Error **errp);
+    void (*type_int8)(Visitor *v, int8_t *obj, const char *name, Error **errp);
+    void (*type_int16)(Visitor *v, int16_t *obj, const char *name, Error **errp);
+    void (*type_int32)(Visitor *v, int32_t *obj, const char *name, Error **errp);
+    void (*type_int64)(Visitor *v, int64_t *obj, const char *name, Error **errp);
+    /* visit_type_size() falls back to (*type_uint64)() if type_size is unset */
+    void (*type_size)(Visitor *v, uint64_t *obj, const char *name, Error **errp);
+};
+
+void visit_start_handle(Visitor *v, void **obj, const char *kind,
+                        const char *name, Error **errp);
+void visit_end_handle(Visitor *v, Error **errp);
+void visit_start_struct(Visitor *v, void **obj, const char *kind,
+                        const char *name, size_t size, Error **errp);
+void visit_end_struct(Visitor *v, Error **errp);
+void visit_start_list(Visitor *v, const char *name, Error **errp);
+GenericList *visit_next_list(Visitor *v, GenericList **list, Error **errp);
+void visit_end_list(Visitor *v, Error **errp);
+void visit_start_optional(Visitor *v, bool *present, const char *name,
+                          Error **errp);
+void visit_end_optional(Visitor *v, Error **errp);
+void visit_type_enum(Visitor *v, int *obj, const char *strings[],
+                     const char *kind, const char *name, Error **errp);
+void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp);
+void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp);
+void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp);
+void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp);
+void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp);
+void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp);
+void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp);
+void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp);
+void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp);
+void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp);
+void visit_type_bool(Visitor *v, bool *obj, const char *name, Error **errp);
+void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp);
+void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp);
+
+#endif
diff --git a/qapi/qapi-visit-impl.h b/qapi/qapi-visit-impl.h
new file mode 100644
index 000000000..0f3a1898f
--- /dev/null
+++ b/qapi/qapi-visit-impl.h
@@ -0,0 +1,23 @@
+/*
+ * Core Definitions for QAPI Visitor implementations
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonizni <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+#ifndef QAPI_VISITOR_IMPL_H
+#define QAPI_VISITOR_IMPL_H
+
+#include "qapi/qapi-types-core.h"
+#include "qapi/qapi-visit-core.h"
+
+void input_type_enum(Visitor *v, int *obj, const char *strings[],
+                     const char *kind, const char *name, Error **errp);
+void output_type_enum(Visitor *v, int *obj, const char *strings[],
+                      const char *kind, const char *name, Error **errp);
+
+#endif
diff --git a/qapi/qmp-core.h b/qapi/qmp-core.h
new file mode 100644
index 000000000..00446cff9
--- /dev/null
+++ b/qapi/qmp-core.h
@@ -0,0 +1,55 @@
+/*
+ * Core Definitions for QAPI/QMP Dispatch
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QMP_CORE_H
+#define QMP_CORE_H
+
+#include "qobject.h"
+#include "qdict.h"
+#include "error.h"
+
+typedef void (QmpCommandFunc)(QDict *, QObject **, Error **);
+
+typedef enum QmpCommandType
+{
+    QCT_NORMAL,
+} QmpCommandType;
+
+typedef enum QmpCommandOptions
+{
+    QCO_NO_OPTIONS = 0x0,
+    QCO_NO_SUCCESS_RESP = 0x1,
+} QmpCommandOptions;
+
+typedef struct QmpCommand
+{
+    const char *name;
+    QmpCommandType type;
+    QmpCommandFunc *fn;
+    QmpCommandOptions options;
+    QTAILQ_ENTRY(QmpCommand) node;
+    bool enabled;
+} QmpCommand;
+
+void qmp_register_command(const char *name, QmpCommandFunc *fn,
+                          QmpCommandOptions options);
+QmpCommand *qmp_find_command(const char *name);
+QObject *qmp_dispatch(QObject *request);
+void qmp_disable_command(const char *name);
+void qmp_enable_command(const char *name);
+bool qmp_command_is_enabled(const char *name);
+char **qmp_get_command_list(void);
+QObject *qmp_build_error_object(Error *errp);
+
+#endif
+
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
new file mode 100644
index 000000000..408599468
--- /dev/null
+++ b/qapi/qmp-dispatch.c
@@ -0,0 +1,139 @@
+/*
+ * Core Definitions for QAPI/QMP Dispatch
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu-objects.h"
+#include "qapi/qmp-core.h"
+#include "json-parser.h"
+#include "qapi-types.h"
+#include "error.h"
+#include "qerror.h"
+
+static QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
+{
+    const QDictEntry *ent;
+    const char *arg_name;
+    const QObject *arg_obj;
+    bool has_exec_key = false;
+    QDict *dict = NULL;
+
+    if (qobject_type(request) != QTYPE_QDICT) {
+        error_set(errp, QERR_QMP_BAD_INPUT_OBJECT,
+                  "request is not a dictionary");
+        return NULL;
+    }
+
+    dict = qobject_to_qdict(request);
+
+    for (ent = qdict_first(dict); ent;
+         ent = qdict_next(dict, ent)) {
+        arg_name = qdict_entry_key(ent);
+        arg_obj = qdict_entry_value(ent);
+
+        if (!strcmp(arg_name, "execute")) {
+            if (qobject_type(arg_obj) != QTYPE_QSTRING) {
+                error_set(errp, QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "execute",
+                          "string");
+                return NULL;
+            }
+            has_exec_key = true;
+        } else if (strcmp(arg_name, "arguments")) {
+            error_set(errp, QERR_QMP_EXTRA_MEMBER, arg_name);
+            return NULL;
+        }
+    }
+
+    if (!has_exec_key) {
+        error_set(errp, QERR_QMP_BAD_INPUT_OBJECT, "execute");
+        return NULL;
+    }
+
+    return dict;
+}
+
+static QObject *do_qmp_dispatch(QObject *request, Error **errp)
+{
+    const char *command;
+    QDict *args, *dict;
+    QmpCommand *cmd;
+    QObject *ret = NULL;
+
+
+    dict = qmp_dispatch_check_obj(request, errp);
+    if (!dict || error_is_set(errp)) {
+        return NULL;
+    }
+
+    command = qdict_get_str(dict, "execute");
+    cmd = qmp_find_command(command);
+    if (cmd == NULL) {
+        error_set(errp, QERR_COMMAND_NOT_FOUND, command);
+        return NULL;
+    }
+    if (!cmd->enabled) {
+        error_set(errp, QERR_COMMAND_DISABLED, command);
+        return NULL;
+    }
+
+    if (!qdict_haskey(dict, "arguments")) {
+        args = qdict_new();
+    } else {
+        args = qdict_get_qdict(dict, "arguments");
+        QINCREF(args);
+    }
+
+    switch (cmd->type) {
+    case QCT_NORMAL:
+        cmd->fn(args, &ret, errp);
+        if (!error_is_set(errp)) {
+            if (cmd->options & QCO_NO_SUCCESS_RESP) {
+                g_assert(!ret);
+            } else if (!ret) {
+                ret = QOBJECT(qdict_new());
+            }
+        }
+        break;
+    }
+
+    QDECREF(args);
+
+    return ret;
+}
+
+QObject *qmp_build_error_object(Error *errp)
+{
+    return qobject_from_jsonf("{ 'class': %s, 'desc': %s }",
+                              ErrorClass_lookup[error_get_class(errp)],
+                              error_get_pretty(errp));
+}
+
+QObject *qmp_dispatch(QObject *request)
+{
+    Error *err = NULL;
+    QObject *ret;
+    QDict *rsp;
+
+    ret = do_qmp_dispatch(request, &err);
+
+    rsp = qdict_new();
+    if (err) {
+        qdict_put_obj(rsp, "error", qmp_build_error_object(err));
+        error_free(err);
+    } else if (ret) {
+        qdict_put_obj(rsp, "return", ret);
+    } else {
+        QDECREF(rsp);
+        return NULL;
+    }
+
+    return QOBJECT(rsp);
+}
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
new file mode 100644
index 000000000..107d8d361
--- /dev/null
+++ b/qapi/qmp-input-visitor.c
@@ -0,0 +1,320 @@
+/*
+ * Input Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qmp-input-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+#include "qerror.h"
+
+#define QIV_STACK_SIZE 1024
+
+typedef struct StackObject
+{
+    QObject *obj;
+    const QListEntry *entry;
+    GHashTable *h;
+} StackObject;
+
+struct QmpInputVisitor
+{
+    Visitor visitor;
+    StackObject stack[QIV_STACK_SIZE];
+    int nb_stack;
+    bool strict;
+};
+
+static QmpInputVisitor *to_qiv(Visitor *v)
+{
+    return container_of(v, QmpInputVisitor, visitor);
+}
+
+static QObject *qmp_input_get_object(QmpInputVisitor *qiv,
+                                     const char *name)
+{
+    QObject *qobj = qiv->stack[qiv->nb_stack - 1].obj;
+
+    if (qobj) {
+        if (name && qobject_type(qobj) == QTYPE_QDICT) {
+            if (qiv->stack[qiv->nb_stack - 1].h) {
+                g_hash_table_remove(qiv->stack[qiv->nb_stack - 1].h, name);
+            }
+            return qdict_get(qobject_to_qdict(qobj), name);
+        } else if (qiv->stack[qiv->nb_stack - 1].entry) {
+            return qlist_entry_obj(qiv->stack[qiv->nb_stack - 1].entry);
+        }
+    }
+
+    return qobj;
+}
+
+static void qdict_add_key(const char *key, QObject *obj, void *opaque)
+{
+    GHashTable *h = opaque;
+    g_hash_table_insert(h, (gpointer) key, NULL);
+}
+
+static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
+{
+    GHashTable *h;
+
+    if (qiv->nb_stack >= QIV_STACK_SIZE) {
+        error_set(errp, QERR_BUFFER_OVERRUN);
+        return;
+    }
+
+    qiv->stack[qiv->nb_stack].obj = obj;
+    qiv->stack[qiv->nb_stack].entry = NULL;
+    qiv->stack[qiv->nb_stack].h = NULL;
+
+    if (qiv->strict && qobject_type(obj) == QTYPE_QDICT) {
+        h = g_hash_table_new(g_str_hash, g_str_equal);
+        qdict_iter(qobject_to_qdict(obj), qdict_add_key, h);
+        qiv->stack[qiv->nb_stack].h = h;
+    }
+
+    qiv->nb_stack++;
+}
+
+/** Only for qmp_input_pop. */
+static gboolean always_true(gpointer key, gpointer val, gpointer user_pkey)
+{
+    *(const char **)user_pkey = (const char *)key;
+    return TRUE;
+}
+
+static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
+{
+    assert(qiv->nb_stack > 0);
+
+    if (qiv->strict) {
+        GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
+        if (top_ht) {
+            if (g_hash_table_size(top_ht)) {
+                const char *key;
+                g_hash_table_find(top_ht, always_true, &key);
+                error_set(errp, QERR_QMP_EXTRA_MEMBER, key);
+            }
+            g_hash_table_unref(top_ht);
+        }
+    }
+
+    qiv->nb_stack--;
+}
+
+static void qmp_input_start_struct(Visitor *v, void **obj, const char *kind,
+                                   const char *name, size_t size, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+    Error *err = NULL;
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QDICT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "QDict");
+        return;
+    }
+
+    qmp_input_push(qiv, qobj, &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+
+    if (obj) {
+        *obj = g_malloc0(size);
+    }
+}
+
+static void qmp_input_end_struct(Visitor *v, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv, errp);
+}
+
+static void qmp_input_start_list(Visitor *v, const char *name, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QLIST) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "list");
+        return;
+    }
+
+    qmp_input_push(qiv, qobj, errp);
+}
+
+static GenericList *qmp_input_next_list(Visitor *v, GenericList **list,
+                                        Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    GenericList *entry;
+    StackObject *so = &qiv->stack[qiv->nb_stack - 1];
+    bool first;
+
+    if (so->entry == NULL) {
+        so->entry = qlist_first(qobject_to_qlist(so->obj));
+        first = true;
+    } else {
+        so->entry = qlist_next(so->entry);
+        first = false;
+    }
+
+    if (so->entry == NULL) {
+        return NULL;
+    }
+
+    entry = g_malloc0(sizeof(*entry));
+    if (first) {
+        *list = entry;
+    } else {
+        (*list)->next = entry;
+    }
+
+    return entry;
+}
+
+static void qmp_input_end_list(Visitor *v, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv, errp);
+}
+
+static void qmp_input_type_int(Visitor *v, int64_t *obj, const char *name,
+                               Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QINT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "integer");
+        return;
+    }
+
+    *obj = qint_get_int(qobject_to_qint(qobj));
+}
+
+static void qmp_input_type_bool(Visitor *v, bool *obj, const char *name,
+                                Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QBOOL) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "boolean");
+        return;
+    }
+
+    *obj = qbool_get_int(qobject_to_qbool(qobj));
+}
+
+static void qmp_input_type_str(Visitor *v, char **obj, const char *name,
+                               Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QSTRING) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "string");
+        return;
+    }
+
+    *obj = g_strdup(qstring_get_str(qobject_to_qstring(qobj)));
+}
+
+static void qmp_input_type_number(Visitor *v, double *obj, const char *name,
+                                  Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || (qobject_type(qobj) != QTYPE_QFLOAT &&
+        qobject_type(qobj) != QTYPE_QINT)) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "number");
+        return;
+    }
+
+    if (qobject_type(qobj) == QTYPE_QINT) {
+        *obj = qint_get_int(qobject_to_qint(qobj));
+    } else {
+        *obj = qfloat_get_double(qobject_to_qfloat(qobj));
+    }
+}
+
+static void qmp_input_start_optional(Visitor *v, bool *present,
+                                     const char *name, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj) {
+        *present = false;
+        return;
+    }
+
+    *present = true;
+}
+
+Visitor *qmp_input_get_visitor(QmpInputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qmp_input_visitor_cleanup(QmpInputVisitor *v)
+{
+    qobject_decref(v->stack[0].obj);
+    g_free(v);
+}
+
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
+{
+    QmpInputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.start_struct = qmp_input_start_struct;
+    v->visitor.end_struct = qmp_input_end_struct;
+    v->visitor.start_list = qmp_input_start_list;
+    v->visitor.next_list = qmp_input_next_list;
+    v->visitor.end_list = qmp_input_end_list;
+    v->visitor.type_enum = input_type_enum;
+    v->visitor.type_int = qmp_input_type_int;
+    v->visitor.type_bool = qmp_input_type_bool;
+    v->visitor.type_str = qmp_input_type_str;
+    v->visitor.type_number = qmp_input_type_number;
+    v->visitor.start_optional = qmp_input_start_optional;
+
+    qmp_input_push(v, obj, NULL);
+    qobject_incref(obj);
+
+    return v;
+}
+
+QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj)
+{
+    QmpInputVisitor *v;
+
+    v = qmp_input_visitor_new(obj);
+    v->strict = true;
+
+    return v;
+}
diff --git a/qapi/qmp-input-visitor.h b/qapi/qmp-input-visitor.h
new file mode 100644
index 000000000..e0a48a5f3
--- /dev/null
+++ b/qapi/qmp-input-visitor.h
@@ -0,0 +1,29 @@
+/*
+ * Input Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QMP_INPUT_VISITOR_H
+#define QMP_INPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+#include "qobject.h"
+
+typedef struct QmpInputVisitor QmpInputVisitor;
+
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj);
+QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj);
+
+void qmp_input_visitor_cleanup(QmpInputVisitor *v);
+
+Visitor *qmp_input_get_visitor(QmpInputVisitor *v);
+
+#endif
diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
new file mode 100644
index 000000000..2bce9d5db
--- /dev/null
+++ b/qapi/qmp-output-visitor.c
@@ -0,0 +1,235 @@
+/*
+ * Core Definitions for QAPI/QMP Command Registry
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qmp-output-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+#include "qerror.h"
+
+typedef struct QStackEntry
+{
+    QObject *value;
+    bool is_list_head;
+    QTAILQ_ENTRY(QStackEntry) node;
+} QStackEntry;
+
+typedef QTAILQ_HEAD(QStack, QStackEntry) QStack;
+
+struct QmpOutputVisitor
+{
+    Visitor visitor;
+    QStack stack;
+};
+
+#define qmp_output_add(qov, name, value) \
+    qmp_output_add_obj(qov, name, QOBJECT(value))
+#define qmp_output_push(qov, value) qmp_output_push_obj(qov, QOBJECT(value))
+
+static QmpOutputVisitor *to_qov(Visitor *v)
+{
+    return container_of(v, QmpOutputVisitor, visitor);
+}
+
+static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value)
+{
+    QStackEntry *e = g_malloc0(sizeof(*e));
+
+    e->value = value;
+    if (qobject_type(e->value) == QTYPE_QLIST) {
+        e->is_list_head = true;
+    }
+    QTAILQ_INSERT_HEAD(&qov->stack, e, node);
+}
+
+static QObject *qmp_output_pop(QmpOutputVisitor *qov)
+{
+    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
+    QObject *value;
+    QTAILQ_REMOVE(&qov->stack, e, node);
+    value = e->value;
+    g_free(e);
+    return value;
+}
+
+static QObject *qmp_output_first(QmpOutputVisitor *qov)
+{
+    QStackEntry *e = QTAILQ_LAST(&qov->stack, QStack);
+    return e->value;
+}
+
+static QObject *qmp_output_last(QmpOutputVisitor *qov)
+{
+    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
+    return e->value;
+}
+
+static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
+                               QObject *value)
+{
+    QObject *cur;
+
+    if (QTAILQ_EMPTY(&qov->stack)) {
+        qmp_output_push_obj(qov, value);
+        return;
+    }
+
+    cur = qmp_output_last(qov);
+
+    switch (qobject_type(cur)) {
+    case QTYPE_QDICT:
+        qdict_put_obj(qobject_to_qdict(cur), name, value);
+        break;
+    case QTYPE_QLIST:
+        qlist_append_obj(qobject_to_qlist(cur), value);
+        break;
+    default:
+        qobject_decref(qmp_output_pop(qov));
+        qmp_output_push_obj(qov, value);
+        break;
+    }
+}
+
+static void qmp_output_start_struct(Visitor *v, void **obj, const char *kind,
+                                    const char *name, size_t unused,
+                                    Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    QDict *dict = qdict_new();
+
+    qmp_output_add(qov, name, dict);
+    qmp_output_push(qov, dict);
+}
+
+static void qmp_output_end_struct(Visitor *v, Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_pop(qov);
+}
+
+static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    QList *list = qlist_new();
+
+    qmp_output_add(qov, name, list);
+    qmp_output_push(qov, list);
+}
+
+static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp,
+                                         Error **errp)
+{
+    GenericList *list = *listp;
+    QmpOutputVisitor *qov = to_qov(v);
+    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
+
+    assert(e);
+    if (e->is_list_head) {
+        e->is_list_head = false;
+        return list;
+    }
+
+    return list ? list->next : NULL;
+}
+
+static void qmp_output_end_list(Visitor *v, Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_pop(qov);
+}
+
+static void qmp_output_type_int(Visitor *v, int64_t *obj, const char *name,
+                                Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_add(qov, name, qint_from_int(*obj));
+}
+
+static void qmp_output_type_bool(Visitor *v, bool *obj, const char *name,
+                                 Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_add(qov, name, qbool_from_int(*obj));
+}
+
+static void qmp_output_type_str(Visitor *v, char **obj, const char *name,
+                                Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    if (*obj) {
+        qmp_output_add(qov, name, qstring_from_str(*obj));
+    } else {
+        qmp_output_add(qov, name, qstring_from_str(""));
+    }
+}
+
+static void qmp_output_type_number(Visitor *v, double *obj, const char *name,
+                                   Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_add(qov, name, qfloat_from_double(*obj));
+}
+
+QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
+{
+    QObject *obj = qmp_output_first(qov);
+    if (obj) {
+        qobject_incref(obj);
+    }
+    return obj;
+}
+
+Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qmp_output_visitor_cleanup(QmpOutputVisitor *v)
+{
+    QStackEntry *e, *tmp;
+
+    /* The bottom QStackEntry, if any, owns the root QObject. See the
+     * qmp_output_push_obj() invocations in qmp_output_add_obj(). */
+    QObject *root = QTAILQ_EMPTY(&v->stack) ? NULL : qmp_output_first(v);
+
+    QTAILQ_FOREACH_SAFE(e, &v->stack, node, tmp) {
+        QTAILQ_REMOVE(&v->stack, e, node);
+        g_free(e);
+    }
+
+    qobject_decref(root);
+    g_free(v);
+}
+
+QmpOutputVisitor *qmp_output_visitor_new(void)
+{
+    QmpOutputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.start_struct = qmp_output_start_struct;
+    v->visitor.end_struct = qmp_output_end_struct;
+    v->visitor.start_list = qmp_output_start_list;
+    v->visitor.next_list = qmp_output_next_list;
+    v->visitor.end_list = qmp_output_end_list;
+    v->visitor.type_enum = output_type_enum;
+    v->visitor.type_int = qmp_output_type_int;
+    v->visitor.type_bool = qmp_output_type_bool;
+    v->visitor.type_str = qmp_output_type_str;
+    v->visitor.type_number = qmp_output_type_number;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}
diff --git a/qapi/qmp-output-visitor.h b/qapi/qmp-output-visitor.h
new file mode 100644
index 000000000..4a649c250
--- /dev/null
+++ b/qapi/qmp-output-visitor.h
@@ -0,0 +1,28 @@
+/*
+ * Output Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QMP_OUTPUT_VISITOR_H
+#define QMP_OUTPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+#include "qobject.h"
+
+typedef struct QmpOutputVisitor QmpOutputVisitor;
+
+QmpOutputVisitor *qmp_output_visitor_new(void);
+void qmp_output_visitor_cleanup(QmpOutputVisitor *v);
+
+QObject *qmp_output_get_qobject(QmpOutputVisitor *v);
+Visitor *qmp_output_get_visitor(QmpOutputVisitor *v);
+
+#endif
diff --git a/qapi/qmp-registry.c b/qapi/qmp-registry.c
new file mode 100644
index 000000000..541461337
--- /dev/null
+++ b/qapi/qmp-registry.c
@@ -0,0 +1,98 @@
+/*
+ * Core Definitions for QAPI/QMP Dispatch
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *  Michael Roth      <mdroth@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qapi/qmp-core.h"
+
+static QTAILQ_HEAD(QmpCommandList, QmpCommand) qmp_commands =
+    QTAILQ_HEAD_INITIALIZER(qmp_commands);
+
+void qmp_register_command(const char *name, QmpCommandFunc *fn,
+                          QmpCommandOptions options)
+{
+    QmpCommand *cmd = g_malloc0(sizeof(*cmd));
+
+    cmd->name = name;
+    cmd->type = QCT_NORMAL;
+    cmd->fn = fn;
+    cmd->enabled = true;
+    cmd->options = options;
+    QTAILQ_INSERT_TAIL(&qmp_commands, cmd, node);
+}
+
+QmpCommand *qmp_find_command(const char *name)
+{
+    QmpCommand *cmd;
+
+    QTAILQ_FOREACH(cmd, &qmp_commands, node) {
+        if (strcmp(cmd->name, name) == 0) {
+            return cmd;
+        }
+    }
+    return NULL;
+}
+
+static void qmp_toggle_command(const char *name, bool enabled)
+{
+    QmpCommand *cmd;
+
+    QTAILQ_FOREACH(cmd, &qmp_commands, node) {
+        if (strcmp(cmd->name, name) == 0) {
+            cmd->enabled = enabled;
+            return;
+        }
+    }
+}
+
+void qmp_disable_command(const char *name)
+{
+    qmp_toggle_command(name, false);
+}
+
+void qmp_enable_command(const char *name)
+{
+    qmp_toggle_command(name, true);
+}
+
+bool qmp_command_is_enabled(const char *name)
+{
+    QmpCommand *cmd;
+
+    QTAILQ_FOREACH(cmd, &qmp_commands, node) {
+        if (strcmp(cmd->name, name) == 0) {
+            return cmd->enabled;
+        }
+    }
+
+    return false;
+}
+
+char **qmp_get_command_list(void)
+{
+    QmpCommand *cmd;
+    int count = 1;
+    char **list_head, **list;
+
+    QTAILQ_FOREACH(cmd, &qmp_commands, node) {
+        count++;
+    }
+
+    list_head = list = g_malloc0(count * sizeof(char *));
+
+    QTAILQ_FOREACH(cmd, &qmp_commands, node) {
+        *list = strdup(cmd->name);
+        list++;
+    }
+
+    return list_head;
+}
diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
new file mode 100644
index 000000000..497eb9a60
--- /dev/null
+++ b/qapi/string-input-visitor.c
@@ -0,0 +1,138 @@
+/*
+ * String parsing visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "string-input-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qerror.h"
+
+struct StringInputVisitor
+{
+    Visitor visitor;
+    const char *string;
+};
+
+static void parse_type_int(Visitor *v, int64_t *obj, const char *name,
+                           Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    char *endp = (char *) siv->string;
+    long long val;
+
+    errno = 0;
+    if (siv->string) {
+        val = strtoll(siv->string, &endp, 0);
+    }
+    if (!siv->string || errno || endp == siv->string || *endp) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "integer");
+        return;
+    }
+
+    *obj = val;
+}
+
+static void parse_type_bool(Visitor *v, bool *obj, const char *name,
+                            Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+
+    if (siv->string) {
+        if (!strcasecmp(siv->string, "on") ||
+            !strcasecmp(siv->string, "yes") ||
+            !strcasecmp(siv->string, "true")) {
+            *obj = true;
+            return;
+        }
+        if (!strcasecmp(siv->string, "off") ||
+            !strcasecmp(siv->string, "no") ||
+            !strcasecmp(siv->string, "false")) {
+            *obj = false;
+            return;
+        }
+    }
+
+    error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+              "boolean");
+}
+
+static void parse_type_str(Visitor *v, char **obj, const char *name,
+                           Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    if (siv->string) {
+        *obj = g_strdup(siv->string);
+    } else {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "string");
+    }
+}
+
+static void parse_type_number(Visitor *v, double *obj, const char *name,
+                              Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    char *endp = (char *) siv->string;
+    double val;
+
+    errno = 0;
+    if (siv->string) {
+        val = strtod(siv->string, &endp);
+    }
+    if (!siv->string || errno || endp == siv->string || *endp) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "number");
+        return;
+    }
+
+    *obj = val;
+}
+
+static void parse_start_optional(Visitor *v, bool *present,
+                                 const char *name, Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+
+    if (!siv->string) {
+        *present = false;
+        return;
+    }
+
+    *present = true;
+}
+
+Visitor *string_input_get_visitor(StringInputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void string_input_visitor_cleanup(StringInputVisitor *v)
+{
+    g_free(v);
+}
+
+StringInputVisitor *string_input_visitor_new(const char *str)
+{
+    StringInputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.type_enum = input_type_enum;
+    v->visitor.type_int = parse_type_int;
+    v->visitor.type_bool = parse_type_bool;
+    v->visitor.type_str = parse_type_str;
+    v->visitor.type_number = parse_type_number;
+    v->visitor.start_optional = parse_start_optional;
+
+    v->string = str;
+    return v;
+}
diff --git a/qapi/string-input-visitor.h b/qapi/string-input-visitor.h
new file mode 100644
index 000000000..d269d42ce
--- /dev/null
+++ b/qapi/string-input-visitor.h
@@ -0,0 +1,25 @@
+/*
+ * String parsing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef STRING_INPUT_VISITOR_H
+#define STRING_INPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct StringInputVisitor StringInputVisitor;
+
+StringInputVisitor *string_input_visitor_new(const char *str);
+void string_input_visitor_cleanup(StringInputVisitor *v);
+
+Visitor *string_input_get_visitor(StringInputVisitor *v);
+
+#endif
diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
new file mode 100644
index 000000000..34e525ead
--- /dev/null
+++ b/qapi/string-output-visitor.c
@@ -0,0 +1,89 @@
+/*
+ * String printing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "string-output-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qerror.h"
+
+struct StringOutputVisitor
+{
+    Visitor visitor;
+    char *string;
+};
+
+static void string_output_set(StringOutputVisitor *sov, char *string)
+{
+    g_free(sov->string);
+    sov->string = string;
+}
+
+static void print_type_int(Visitor *v, int64_t *obj, const char *name,
+                           Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup_printf("%lld", (long long) *obj));
+}
+
+static void print_type_bool(Visitor *v, bool *obj, const char *name,
+                            Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup(*obj ? "true" : "false"));
+}
+
+static void print_type_str(Visitor *v, char **obj, const char *name,
+                           Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup(*obj ? *obj : ""));
+}
+
+static void print_type_number(Visitor *v, double *obj, const char *name,
+                              Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup_printf("%f", *obj));
+}
+
+char *string_output_get_string(StringOutputVisitor *sov)
+{
+    char *string = sov->string;
+    sov->string = NULL;
+    return string;
+}
+
+Visitor *string_output_get_visitor(StringOutputVisitor *sov)
+{
+    return &sov->visitor;
+}
+
+void string_output_visitor_cleanup(StringOutputVisitor *sov)
+{
+    g_free(sov->string);
+    g_free(sov);
+}
+
+StringOutputVisitor *string_output_visitor_new(void)
+{
+    StringOutputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.type_enum = output_type_enum;
+    v->visitor.type_int = print_type_int;
+    v->visitor.type_bool = print_type_bool;
+    v->visitor.type_str = print_type_str;
+    v->visitor.type_number = print_type_number;
+
+    return v;
+}
diff --git a/qapi/string-output-visitor.h b/qapi/string-output-visitor.h
new file mode 100644
index 000000000..886845411
--- /dev/null
+++ b/qapi/string-output-visitor.h
@@ -0,0 +1,26 @@
+/*
+ * String printing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef STRING_OUTPUT_VISITOR_H
+#define STRING_OUTPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct StringOutputVisitor StringOutputVisitor;
+
+StringOutputVisitor *string_output_visitor_new(void);
+void string_output_visitor_cleanup(StringOutputVisitor *v);
+
+char *string_output_get_string(StringOutputVisitor *v);
+Visitor *string_output_get_visitor(StringOutputVisitor *v);
+
+#endif