Merge remote-tracking branch 'remotes/juanquintela/tags/migration/20140623' into staging

migration/next for 20140623

# gpg: Signature made Mon 23 Jun 2014 18:18:57 BST using RSA key ID 5872D723
# gpg: Can't check signature: public key not found

* remotes/juanquintela/tags/migration/20140623: (22 commits)
  vmstate: Refactor & increase tests for primitive types
  vmstate: Return error in case of error
  migration: Remove unneeded minimum_version_id_old
  tests: vmstate static checker: add size mismatch inside substructure
  tests: vmstate static checker: add substructure for usb-kbd for hid section
  tests: vmstate static checker: remove Subsections
  tests: vmstate static checker: remove a subsection
  tests: vmstate static checker: remove Description inside Fields
  tests: vmstate static checker: remove Description
  tests: vmstate static checker: remove Fields
  tests: vmstate static checker: change description name
  tests: vmstate static checker: remove last field in a struct
  tests: vmstate static checker: remove a field
  tests: vmstate static checker: remove a section
  tests: vmstate static checker: minimum_version_id check
  tests: vmstate static checker: version mismatch inside a Description
  tests: vmstate static checker: add version error in main section
  tests: vmstate static checker: incompat machine types
  tests: vmstate static checker: add dump1 and dump2 files
  vmstate-static-checker: script to validate vmstate changes
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/usb/hcd-ohci.c

@@ -1988,8 +1988,7 @@ static const VMStateDescription vmstate_ohci_state_port = {
     .name = "ohci-core/port",
     .version_id = 1,
     .minimum_version_id = 1,
-    .minimum_version_id_old = 1,
-    .fields = (VMStateField []) {
+    .fields = (VMStateField[]) {
         VMSTATE_UINT32(ctrl, OHCIPort),
         VMSTATE_END_OF_LIST()
     },
@@ -2015,9 +2014,8 @@ static const VMStateDescription vmstate_ohci_eof_timer = {
     .name = "ohci-core/eof-timer",
     .version_id = 1,
     .minimum_version_id = 1,
-    .minimum_version_id_old = 1,
     .pre_load = ohci_eof_timer_pre_load,
-    .fields = (VMStateField []) {
+    .fields = (VMStateField[]) {
         VMSTATE_TIMER(eof_timer, OHCIState),
         VMSTATE_END_OF_LIST()
     },
@@ -2078,7 +2076,6 @@ static const VMStateDescription vmstate_ohci = {
     .name = "ohci",
     .version_id = 1,
     .minimum_version_id = 1,
-    .minimum_version_id_old = 1,
     .fields = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(parent_obj, OHCIPCIState),
         VMSTATE_STRUCT(state, OHCIPCIState, 1, vmstate_ohci_state, OHCIState),

include/migration/vmstate.h

@@ -788,4 +788,6 @@ int64_t self_announce_delay(int round)
     return 50 + (SELF_ANNOUNCE_ROUNDS - round - 1) * 100;
 }
 
+void dump_vmstate_json_to_file(FILE *out_fp);
+
 #endif

migration-rdma.c

@@ -1590,13 +1590,11 @@ static int qemu_rdma_post_send_control(RDMAContext *rdma, uint8_t *buf,
     }
 
 
-    if (ibv_post_send(rdma->qp, &send_wr, &bad_wr)) {
-        return -1;
-    }
+    ret = ibv_post_send(rdma->qp, &send_wr, &bad_wr);
 
-    if (ret < 0) {
+    if (ret > 0) {
         fprintf(stderr, "Failed to use post IB SEND for control!\n");
-        return ret;
+        return -ret;
     }
 
     ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_SEND_CONTROL, NULL);
@@ -2238,10 +2236,6 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
         }
     }
 
-    if (rdma->qp) {
-        rdma_destroy_qp(rdma->cm_id);
-        rdma->qp = NULL;
-    }
     if (rdma->cq) {
         ibv_destroy_cq(rdma->cq);
         rdma->cq = NULL;
@@ -2259,6 +2253,10 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
         rdma->listen_id = NULL;
     }
     if (rdma->cm_id) {
+        if (rdma->qp) {
+            rdma_destroy_qp(rdma->cm_id);
+            rdma->qp = NULL;
+        }
         rdma_destroy_id(rdma->cm_id);
         rdma->cm_id = NULL;
     }
@@ -2513,8 +2511,10 @@ static void *qemu_rdma_data_init(const char *host_port, Error **errp)
         } else {
             ERROR(errp, "bad RDMA migration address '%s'", host_port);
             g_free(rdma);
-            return NULL;
+            rdma = NULL;
         }
+
+        qapi_free_InetSocketAddress(addr);
     }
 
     return rdma;

qemu-options.hx

@@ -3252,6 +3252,20 @@ STEXI
 prepend a timestamp to each log message.(default:on)
 ETEXI
 
+DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
+    "-dump-vmstate <file>\n"
+    "                Output vmstate information in JSON format to file.\n"
+    "                Use the scripts/vmstate-static-checker.py file to\n"
+    "                check for possible regressions in migration code\n"
+    "                by comparing two such vmstate dumps.",
+    QEMU_ARCH_ALL)
+STEXI
+@item -dump-vmstate @var{file}
+@findex -dump-vmstate
+Dump json-encoded vmstate information for current machine type to file
+in @var{file}
+ETEXI
+
 HXCOMM This is the last statement. Insert new options before this line!
 STEXI
 @end table

savevm.c

@@ -24,6 +24,7 @@
 
 #include "config-host.h"
 #include "qemu-common.h"
+#include "hw/boards.h"
 #include "hw/hw.h"
 #include "hw/qdev.h"
 #include "net/net.h"
@@ -240,6 +241,144 @@ static QTAILQ_HEAD(savevm_handlers, SaveStateEntry) savevm_handlers =
     QTAILQ_HEAD_INITIALIZER(savevm_handlers);
 static int global_section_id;
 
+static void dump_vmstate_vmsd(FILE *out_file,
+                              const VMStateDescription *vmsd, int indent,
+                              bool is_subsection);
+
+static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field,
+                              int indent)
+{
+    fprintf(out_file, "%*s{\n", indent, "");
+    indent += 2;
+    fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name);
+    fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+            field->version_id);
+    fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "",
+            field->field_exists ? "true" : "false");
+    fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size);
+    if (field->vmsd != NULL) {
+        fprintf(out_file, ",\n");
+        dump_vmstate_vmsd(out_file, field->vmsd, indent, false);
+    }
+    fprintf(out_file, "\n%*s}", indent - 2, "");
+}
+
+static void dump_vmstate_vmss(FILE *out_file,
+                              const VMStateSubsection *subsection,
+                              int indent)
+{
+    if (subsection->vmsd != NULL) {
+        dump_vmstate_vmsd(out_file, subsection->vmsd, indent, true);
+    }
+}
+
+static void dump_vmstate_vmsd(FILE *out_file,
+                              const VMStateDescription *vmsd, int indent,
+                              bool is_subsection)
+{
+    if (is_subsection) {
+        fprintf(out_file, "%*s{\n", indent, "");
+    } else {
+        fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description");
+    }
+    indent += 2;
+    fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name);
+    fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+            vmsd->version_id);
+    fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "",
+            vmsd->minimum_version_id);
+    if (vmsd->fields != NULL) {
+        const VMStateField *field = vmsd->fields;
+        bool first;
+
+        fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, "");
+        first = true;
+        while (field->name != NULL) {
+            if (field->flags & VMS_MUST_EXIST) {
+                /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */
+                field++;
+                continue;
+            }
+            if (!first) {
+                fprintf(out_file, ",\n");
+            }
+            dump_vmstate_vmsf(out_file, field, indent + 2);
+            field++;
+            first = false;
+        }
+        fprintf(out_file, "\n%*s]", indent, "");
+    }
+    if (vmsd->subsections != NULL) {
+        const VMStateSubsection *subsection = vmsd->subsections;
+        bool first;
+
+        fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, "");
+        first = true;
+        while (subsection->vmsd != NULL) {
+            if (!first) {
+                fprintf(out_file, ",\n");
+            }
+            dump_vmstate_vmss(out_file, subsection, indent + 2);
+            subsection++;
+            first = false;
+        }
+        fprintf(out_file, "\n%*s]", indent, "");
+    }
+    fprintf(out_file, "\n%*s}", indent - 2, "");
+}
+
+static void dump_machine_type(FILE *out_file)
+{
+    MachineClass *mc;
+
+    mc = MACHINE_GET_CLASS(current_machine);
+
+    fprintf(out_file, "  \"vmschkmachine\": {\n");
+    fprintf(out_file, "    \"Name\": \"%s\"\n", mc->name);
+    fprintf(out_file, "  },\n");
+}
+
+void dump_vmstate_json_to_file(FILE *out_file)
+{
+    GSList *list, *elt;
+    bool first;
+
+    fprintf(out_file, "{\n");
+    dump_machine_type(out_file);
+
+    first = true;
+    list = object_class_get_list(TYPE_DEVICE, true);
+    for (elt = list; elt; elt = elt->next) {
+        DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data,
+                                             TYPE_DEVICE);
+        const char *name;
+        int indent = 2;
+
+        if (!dc->vmsd) {
+            continue;
+        }
+
+        if (!first) {
+            fprintf(out_file, ",\n");
+        }
+        name = object_class_get_name(OBJECT_CLASS(dc));
+        fprintf(out_file, "%*s\"%s\": {\n", indent, "", name);
+        indent += 2;
+        fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name);
+        fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "",
+                dc->vmsd->version_id);
+        fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "",
+                dc->vmsd->minimum_version_id);
+
+        dump_vmstate_vmsd(out_file, dc->vmsd, indent, false);
+
+        fprintf(out_file, "\n%*s}", indent - 2, "");
+        first = false;
+    }
+    fprintf(out_file, "\n}\n");
+    fclose(out_file);
+}
+
 static int calculate_new_instance_id(const char *idstr)
 {
     SaveStateEntry *se;

scripts/vmstate-static-checker.py

+#!/usr/bin/python
+#
+# Compares vmstate information stored in JSON format, obtained from
+# the -dump-vmstate QEMU command.
+#
+# Copyright 2014 Amit Shah <amit.shah@redhat.com>
+# Copyright 2014 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, see <http://www.gnu.org/licenses/>.
+
+import argparse
+import json
+import sys
+
+# Count the number of errors found
+taint = 0
+
+def bump_taint():
+    global taint
+
+    # Ensure we don't wrap around or reset to 0 -- the shell only has
+    # an 8-bit return value.
+    if taint < 255:
+        taint = taint + 1
+
+
+def check_fields_match(name, s_field, d_field):
+    if s_field == d_field:
+        return True
+
+    # Some fields changed names between qemu versions.  This list
+    # is used to whitelist such changes in each section / description.
+    changed_names = {
+        'e1000': ['dev', 'parent_obj'],
+        'ehci': ['dev', 'pcidev'],
+        'I440FX': ['dev', 'parent_obj'],
+        'ich9_ahci': ['card', 'parent_obj'],
+        'ioh-3240-express-root-port': ['port.br.dev',
+                                       'parent_obj.parent_obj.parent_obj',
+                                       'port.br.dev.exp.aer_log',
+                                'parent_obj.parent_obj.parent_obj.exp.aer_log'],
+        'mch': ['d', 'parent_obj'],
+        'pci_bridge': ['bridge.dev', 'parent_obj', 'bridge.dev.shpc', 'shpc'],
+        'pcnet': ['pci_dev', 'parent_obj'],
+        'PIIX3': ['pci_irq_levels', 'pci_irq_levels_vmstate'],
+        'piix4_pm': ['dev', 'parent_obj', 'pci0_status',
+                     'acpi_pci_hotplug.acpi_pcihp_pci_status[0x0]'],
+        'rtl8139': ['dev', 'parent_obj'],
+        'qxl': ['num_surfaces', 'ssd.num_surfaces'],
+        'usb-host': ['dev', 'parent_obj'],
+        'usb-mouse': ['usb-ptr-queue', 'HIDPointerEventQueue'],
+        'usb-tablet': ['usb-ptr-queue', 'HIDPointerEventQueue'],
+        'xhci': ['pci_dev', 'parent_obj'],
+        'xio3130-express-downstream-port': ['port.br.dev',
+                                            'parent_obj.parent_obj.parent_obj',
+                                            'port.br.dev.exp.aer_log',
+                                'parent_obj.parent_obj.parent_obj.exp.aer_log'],
+        'xio3130-express-upstream-port': ['br.dev', 'parent_obj.parent_obj',
+                                          'br.dev.exp.aer_log',
+                                          'parent_obj.parent_obj.exp.aer_log'],
+    }
+
+    if not name in changed_names:
+        return False
+
+    if s_field in changed_names[name] and d_field in changed_names[name]:
+        return True
+
+    return False
+
+
+def exists_in_substruct(fields, item):
+    # Some QEMU versions moved a few fields inside a substruct.  This
+    # kept the on-wire format the same.  This function checks if
+    # something got shifted inside a substruct.  For example, the
+    # change in commit 1f42d22233b4f3d1a2933ff30e8d6a6d9ee2d08f
+
+    if not "Description" in fields:
+        return False
+
+    if not "Fields" in fields["Description"]:
+        return False
+
+    substruct_fields = fields["Description"]["Fields"]
+
+    if substruct_fields == []:
+        return False
+
+    return check_fields_match(fields["Description"]["name"],
+                              substruct_fields[0]["field"], item)
+
+
+def check_fields(src_fields, dest_fields, desc, sec):
+    # This function checks for all the fields in a section.  If some
+    # fields got embedded into a substruct, this function will also
+    # attempt to check inside the substruct.
+
+    d_iter = iter(dest_fields)
+    s_iter = iter(src_fields)
+
+    # Using these lists as stacks to store previous value of s_iter
+    # and d_iter, so that when time comes to exit out of a substruct,
+    # we can go back one level up and continue from where we left off.
+
+    s_iter_list = []
+    d_iter_list = []
+
+    advance_src = True
+    advance_dest = True
+
+    while True:
+        if advance_src:
+            try:
+                s_item = s_iter.next()
+            except StopIteration:
+                if s_iter_list == []:
+                    break
+
+                s_iter = s_iter_list.pop()
+                continue
+        else:
+            # We want to avoid advancing just once -- when entering a
+            # dest substruct, or when exiting one.
+            advance_src = True
+
+        if advance_dest:
+            try:
+                d_item = d_iter.next()
+            except StopIteration:
+                if d_iter_list == []:
+                    # We were not in a substruct
+                    print "Section \"" + sec + "\",",
+                    print "Description " + "\"" + desc + "\":",
+                    print "expected field \"" + s_item["field"] + "\",",
+                    print "while dest has no further fields"
+                    bump_taint()
+                    break
+
+                d_iter = d_iter_list.pop()
+                advance_src = False
+                continue
+        else:
+            advance_dest = True
+
+        if not check_fields_match(desc, s_item["field"], d_item["field"]):
+            # Some fields were put in substructs, keeping the
+            # on-wire format the same, but breaking static tools
+            # like this one.
+
+            # First, check if dest has a new substruct.
+            if exists_in_substruct(d_item, s_item["field"]):
+                # listiterators don't have a prev() function, so we
+                # have to store our current location, descend into the
+                # substruct, and ensure we come out as if nothing
+                # happened when the substruct is over.
+                #
+                # Essentially we're opening the substructs that got
+                # added which didn't change the wire format.
+                d_iter_list.append(d_iter)
+                substruct_fields = d_item["Description"]["Fields"]
+                d_iter = iter(substruct_fields)
+                advance_src = False
+                continue
+
+            # Next, check if src has substruct that dest removed
+            # (can happen in backward migration: 2.0 -> 1.5)
+            if exists_in_substruct(s_item, d_item["field"]):
+                s_iter_list.append(s_iter)
+                substruct_fields = s_item["Description"]["Fields"]
+                s_iter = iter(substruct_fields)
+                advance_dest = False
+                continue
+
+            print "Section \"" + sec + "\",",
+            print "Description \"" + desc + "\":",
+            print "expected field \"" + s_item["field"] + "\",",
+            print "got \"" + d_item["field"] + "\"; skipping rest"
+            bump_taint()
+            break
+
+        check_version(s_item, d_item, sec, desc)
+
+        if not "Description" in s_item:
+            # Check size of this field only if it's not a VMSTRUCT entry
+            check_size(s_item, d_item, sec, desc, s_item["field"])
+
+        check_description_in_list(s_item, d_item, sec, desc)
+
+
+def check_subsections(src_sub, dest_sub, desc, sec):
+    for s_item in src_sub:
+        found = False
+        for d_item in dest_sub:
+            if s_item["name"] != d_item["name"]:
+                continue
+
+            found = True
+            check_descriptions(s_item, d_item, sec)
+
+        if not found:
+            print "Section \"" + sec + "\", Description \"" + desc + "\":",
+            print "Subsection \"" + s_item["name"] + "\" not found"
+            bump_taint()
+
+
+def check_description_in_list(s_item, d_item, sec, desc):
+    if not "Description" in s_item:
+        return
+
+    if not "Description" in d_item:
+        print "Section \"" + sec + "\", Description \"" + desc + "\",",
+        print "Field \"" + s_item["field"] + "\": missing description"
+        bump_taint()
+        return
+
+    check_descriptions(s_item["Description"], d_item["Description"], sec)
+
+
+def check_descriptions(src_desc, dest_desc, sec):
+    check_version(src_desc, dest_desc, sec, src_desc["name"])
+
+    if not check_fields_match(sec, src_desc["name"], dest_desc["name"]):
+        print "Section \"" + sec + "\":",
+        print "Description \"" + src_desc["name"] + "\"",
+        print "missing, got \"" + dest_desc["name"] + "\" instead; skipping"
+        bump_taint()
+        return
+
+    for f in src_desc:
+        if not f in dest_desc:
+            print "Section \"" + sec + "\"",
+            print "Description \"" + src_desc["name"] + "\":",
+            print "Entry \"" + f + "\" missing"
+            bump_taint()
+            continue
+
+        if f == 'Fields':
+            check_fields(src_desc[f], dest_desc[f], src_desc["name"], sec)
+
+        if f == 'Subsections':
+            check_subsections(src_desc[f], dest_desc[f], src_desc["name"], sec)
+
+
+def check_version(s, d, sec, desc=None):
+    if s["version_id"] > d["version_id"]:
+        print "Section \"" + sec + "\"",
+        if desc:
+            print "Description \"" + desc + "\":",
+        print "version error:", s["version_id"], ">", d["version_id"]
+        bump_taint()
+
+    if not "minimum_version_id" in d:
+        return
+
+    if s["version_id"] < d["minimum_version_id"]:
+        print "Section \"" + sec + "\"",
+        if desc:
+            print "Description \"" + desc + "\":",
+            print "minimum version error:", s["version_id"], "<",
+            print d["minimum_version_id"]
+            bump_taint()
+
+
+def check_size(s, d, sec, desc=None, field=None):
+    if s["size"] != d["size"]:
+        print "Section \"" + sec + "\"",
+        if desc:
+            print "Description \"" + desc + "\"",
+        if field:
+            print "Field \"" + field + "\"",
+        print "size mismatch:", s["size"], ",", d["size"]
+        bump_taint()
+
+
+def check_machine_type(s, d):
+    if s["Name"] != d["Name"]:
+        print "Warning: checking incompatible machine types:",
+        print "\"" + s["Name"] + "\", \"" + d["Name"] + "\""
+    return
+
+
+def main():
+    help_text = "Parse JSON-formatted vmstate dumps from QEMU in files SRC and DEST.  Checks whether migration from SRC to DEST QEMU versions would break based on the VMSTATE information contained within the JSON outputs.  The JSON output is created from a QEMU invocation with the -dump-vmstate parameter and a filename argument to it.  Other parameters to QEMU do not matter, except the -M (machine type) parameter."
+
+    parser = argparse.ArgumentParser(description=help_text)
+    parser.add_argument('-s', '--src', type=file, required=True,
+                        help='json dump from src qemu')
+    parser.add_argument('-d', '--dest', type=file, required=True,
+                        help='json dump from dest qemu')
+    parser.add_argument('--reverse', required=False, default=False,
+                        action='store_true',
+                        help='reverse the direction')
+    args = parser.parse_args()
+
+    src_data = json.load(args.src)
+    dest_data = json.load(args.dest)
+    args.src.close()
+    args.dest.close()
+
+    if args.reverse:
+        temp = src_data
+        src_data = dest_data
+        dest_data = temp
+
+    for sec in src_data:
+        if not sec in dest_data:
+            print "Section \"" + sec + "\" does not exist in dest"
+            bump_taint()
+            continue
+
+        s = src_data[sec]
+        d = dest_data[sec]
+
+        if sec == "vmschkmachine":
+            check_machine_type(s, d)
+            continue
+
+        check_version(s, d, sec)
+
+        for entry in s:
+            if not entry in d:
+                print "Section \"" + sec + "\": Entry \"" + entry + "\"",
+                print "missing"
+                bump_taint()
+                continue
+
+            if entry == "Description":
+                check_descriptions(s[entry], d[entry], sec)
+
+    return taint
+
+
+if __name__ == '__main__':
+    sys.exit(main())

tests/test-vmstate.c

@@ -54,80 +54,232 @@ static QEMUFile *open_test_file(bool write)
     return qemu_fdopen(fd, write ? "wb" : "rb");
 }
 
-typedef struct TestSruct {
-    uint32_t a, b, c, e;
-    uint64_t d, f;
-    bool skip_c_e;
-} TestStruct;
+#define SUCCESS(val) \
+    g_assert_cmpint((val), ==, 0)
 
+#define FAILURE(val) \
+    g_assert_cmpint((val), !=, 0)
 
-static const VMStateDescription vmstate_simple = {
-    .name = "test",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_UINT32(a, TestStruct),
-        VMSTATE_UINT32(b, TestStruct),
-        VMSTATE_UINT32(c, TestStruct),
-        VMSTATE_UINT64(d, TestStruct),
-        VMSTATE_END_OF_LIST()
-    }
-};
+static void save_vmstate(const VMStateDescription *desc, void *obj)
+{
+    QEMUFile *f = open_test_file(true);
+
+    /* Save file with vmstate */
+    vmstate_save_state(f, desc, obj);
+    qemu_put_byte(f, QEMU_VM_EOF);
+    g_assert(!qemu_file_get_error(f));
+    qemu_fclose(f);
+}
 
-static void test_simple_save(void)
+static void compare_vmstate(uint8_t *wire, size_t size)
 {
-    QEMUFile *fsave = open_test_file(true);
-    TestStruct obj = { .a = 1, .b = 2, .c = 3, .d = 4 };
-    vmstate_save_state(fsave, &vmstate_simple, &obj);
-    g_assert(!qemu_file_get_error(fsave));
-    qemu_fclose(fsave);
+    QEMUFile *f = open_test_file(false);
+    uint8_t result[size];
 
-    QEMUFile *loading = open_test_file(false);
-    uint8_t expected[] = {
-        0, 0, 0, 1, /* a */
-        0, 0, 0, 2, /* b */
-        0, 0, 0, 3, /* c */
-        0, 0, 0, 0, 0, 0, 0, 4, /* d */
-    };
-    uint8_t result[sizeof(expected)];
-    g_assert_cmpint(qemu_get_buffer(loading, result, sizeof(result)), ==,
+    /* read back as binary */
+
+    g_assert_cmpint(qemu_get_buffer(f, result, sizeof(result)), ==,
                     sizeof(result));
-    g_assert(!qemu_file_get_error(loading));
-    g_assert_cmpint(memcmp(result, expected, sizeof(result)), ==, 0);
+    g_assert(!qemu_file_get_error(f));
+
+    /* Compare that what is on the file is the same that what we
+       expected to be there */
+    SUCCESS(memcmp(result, wire, sizeof(result)));
 
     /* Must reach EOF */
-    qemu_get_byte(loading);
-    g_assert_cmpint(qemu_file_get_error(loading), ==, -EIO);
+    qemu_get_byte(f);
+    g_assert_cmpint(qemu_file_get_error(f), ==, -EIO);
 
-    qemu_fclose(loading);
+    qemu_fclose(f);
 }
 
-static void test_simple_load(void)
+static int load_vmstate_one(const VMStateDescription *desc, void *obj,
+                            int version, uint8_t *wire, size_t size)
 {
-    QEMUFile *fsave = open_test_file(true);
-    uint8_t buf[] = {
-        0, 0, 0, 10,             /* a */
-        0, 0, 0, 20,             /* b */
-        0, 0, 0, 30,             /* c */
-        0, 0, 0, 0, 0, 0, 0, 40, /* d */
-        QEMU_VM_EOF, /* just to ensure we won't get EOF reported prematurely */
-    };
-    qemu_put_buffer(fsave, buf, sizeof(buf));
-    qemu_fclose(fsave);
+    QEMUFile *f;
+    int ret;
+
+    f = open_test_file(true);
+    qemu_put_buffer(f, wire, size);
+    qemu_fclose(f);
+
+    f = open_test_file(false);
+    ret = vmstate_load_state(f, desc, obj, version);
+    if (ret) {
+        g_assert(qemu_file_get_error(f));
+    } else{
+        g_assert(!qemu_file_get_error(f));
+    }
+    qemu_fclose(f);
+    return ret;
+}
 
-    QEMUFile *loading = open_test_file(false);
-    TestStruct obj;
-    vmstate_load_state(loading, &vmstate_simple, &obj, 1);
-    g_assert(!qemu_file_get_error(loading));
-    g_assert_cmpint(obj.a, ==, 10);
-    g_assert_cmpint(obj.b, ==, 20);
-    g_assert_cmpint(obj.c, ==, 30);
-    g_assert_cmpint(obj.d, ==, 40);
-    qemu_fclose(loading);
+
+static int load_vmstate(const VMStateDescription *desc,
+                        void *obj, void *obj_clone,
+                        void (*obj_copy)(void *, void*),
+                        int version, uint8_t *wire, size_t size)
+{
+    /* We test with zero size */
+    obj_copy(obj_clone, obj);
+    FAILURE(load_vmstate_one(desc, obj, version, wire, 0));
+
+    /* Stream ends with QEMU_EOF, so we need at least 3 bytes to be
+     * able to test in the middle */
+
+    if (size > 3) {
+
+        /* We test with size - 2. We can't test size - 1 due to EOF tricks */
+        obj_copy(obj, obj_clone);
+        FAILURE(load_vmstate_one(desc, obj, version, wire, size - 2));
+
+        /* Test with size/2, first half of real state */
+        obj_copy(obj, obj_clone);
+        FAILURE(load_vmstate_one(desc, obj, version, wire, size/2));
+
+        /* Test with size/2, second half of real state */
+        obj_copy(obj, obj_clone);
+        FAILURE(load_vmstate_one(desc, obj, version, wire + (size/2), size/2));
+
+    }
+    obj_copy(obj, obj_clone);
+    return load_vmstate_one(desc, obj, version, wire, size);
+}
+
+/* Test struct that we are going to use for our tests */
+
+typedef struct TestSimple {
+    bool     b_1,   b_2;
+    uint8_t  u8_1;
+    uint16_t u16_1;
+    uint32_t u32_1;
+    uint64_t u64_1;
+    int8_t   i8_1,  i8_2;
+    int16_t  i16_1, i16_2;
+    int32_t  i32_1, i32_2;
+    int64_t  i64_1, i64_2;
+} TestSimple;
+
+/* Object instantiation, we are going to use it in more than one test */
+
+TestSimple obj_simple = {
+    .b_1 = true,
+    .b_2 = false,
+    .u8_1 = 130,
+    .u16_1 = 512,
+    .u32_1 = 70000,
+    .u64_1 = 12121212,
+    .i8_1 = 65,
+    .i8_2 = -65,
+    .i16_1 = 512,
+    .i16_2 = -512,
+    .i32_1 = 70000,
+    .i32_2 = -70000,
+    .i64_1 = 12121212,
+    .i64_2 = -12121212,
+};
+
+/* Description of the values.  If you add a primitive type
+   you are expected to add a test here */
+
+static const VMStateDescription vmstate_simple_primitive = {
+    .name = "simple/primitive",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(b_1, TestSimple),
+        VMSTATE_BOOL(b_2, TestSimple),
+        VMSTATE_UINT8(u8_1, TestSimple),
+        VMSTATE_UINT16(u16_1, TestSimple),
+        VMSTATE_UINT32(u32_1, TestSimple),
+        VMSTATE_UINT64(u64_1, TestSimple),
+        VMSTATE_INT8(i8_1, TestSimple),
+        VMSTATE_INT8(i8_2, TestSimple),
+        VMSTATE_INT16(i16_1, TestSimple),
+        VMSTATE_INT16(i16_2, TestSimple),
+        VMSTATE_INT32(i32_1, TestSimple),
+        VMSTATE_INT32(i32_2, TestSimple),
+        VMSTATE_INT64(i64_1, TestSimple),
+        VMSTATE_INT64(i64_2, TestSimple),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+/* It describes what goes through the wire.  Our tests are basically:
+
+   * save test
+     - save a struct a vmstate to a file
+     - read that file back (binary read, no vmstate)
+     - compare it with what we expect to be on the wire
+   * load test
+     - save to the file what we expect to be on the wire
+     - read struct back with vmstate in a different
+     - compare back with the original struct
+*/
+
+uint8_t wire_simple_primitive[] = {
+    /* b_1 */   0x01,
+    /* b_2 */   0x00,
+    /* u8_1 */  0x82,
+    /* u16_1 */ 0x02, 0x00,
+    /* u32_1 */ 0x00, 0x01, 0x11, 0x70,
+    /* u64_1 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0xb8, 0xf4, 0x7c,
+    /* i8_1 */  0x41,
+    /* i8_2 */  0xbf,
+    /* i16_1 */ 0x02, 0x00,
+    /* i16_2 */ 0xfe, 0x0,
+    /* i32_1 */ 0x00, 0x01, 0x11, 0x70,
+    /* i32_2 */ 0xff, 0xfe, 0xee, 0x90,
+    /* i64_1 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0xb8, 0xf4, 0x7c,
+    /* i64_2 */ 0xff, 0xff, 0xff, 0xff, 0xff, 0x47, 0x0b, 0x84,
+    QEMU_VM_EOF, /* just to ensure we won't get EOF reported prematurely */
+};
+
+static void obj_simple_copy(void *target, void *source)
+{
+    memcpy(target, source, sizeof(TestSimple));
+}
+
+static void test_simple_primitive(void)
+{
+    TestSimple obj, obj_clone;
+
+    memset(&obj, 0, sizeof(obj));
+    save_vmstate(&vmstate_simple_primitive, &obj_simple);
+
+    compare_vmstate(wire_simple_primitive, sizeof(wire_simple_primitive));
+
+    SUCCESS(load_vmstate(&vmstate_simple_primitive, &obj, &obj_clone,
+                         obj_simple_copy, 1, wire_simple_primitive,
+                         sizeof(wire_simple_primitive)));
+
+#define FIELD_EQUAL(name)   g_assert_cmpint(obj.name, ==, obj_simple.name)
+
+    FIELD_EQUAL(b_1);
+    FIELD_EQUAL(b_2);
+    FIELD_EQUAL(u8_1);
+    FIELD_EQUAL(u16_1);
+    FIELD_EQUAL(u32_1);
+    FIELD_EQUAL(u64_1);
+    FIELD_EQUAL(i8_1);
+    FIELD_EQUAL(i8_2);
+    FIELD_EQUAL(i16_1);
+    FIELD_EQUAL(i16_2);
+    FIELD_EQUAL(i32_1);
+    FIELD_EQUAL(i32_2);
+    FIELD_EQUAL(i64_1);
+    FIELD_EQUAL(i64_2);
 }
+#undef FIELD_EQUAL
+
+typedef struct TestStruct {
+    uint32_t a, b, c, e;
+    uint64_t d, f;
+    bool skip_c_e;
+} TestStruct;
 
 static const VMStateDescription vmstate_versioned = {
-    .name = "test",
+    .name = "test/versioned",
     .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
@@ -202,7 +354,7 @@ static bool test_skip(void *opaque, int version_id)
 }
 
 static const VMStateDescription vmstate_skipping = {
-    .name = "test",
+    .name = "test/skip",
     .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
@@ -337,8 +489,7 @@ int main(int argc, char **argv)
     temp_fd = mkstemp(temp_file);
 
     g_test_init(&argc, &argv, NULL);
-    g_test_add_func("/vmstate/simple/save", test_simple_save);
-    g_test_add_func("/vmstate/simple/load", test_simple_load);
+    g_test_add_func("/vmstate/simple/primitive", test_simple_primitive);
     g_test_add_func("/vmstate/versioned/load/v1", test_load_v1);
     g_test_add_func("/vmstate/versioned/load/v2", test_load_v2);
     g_test_add_func("/vmstate/field_exists/load/noskip", test_load_noskip);

vl.c

@@ -2931,6 +2931,7 @@ int main(int argc, char **argv, char **envp)
                                         1024 * 1024;
     ram_addr_t maxram_size = default_ram_size;
     uint64_t ram_slots = 0;
+    FILE *vmstate_dump_file = NULL;
 
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
@@ -3937,6 +3938,13 @@ int main(int argc, char **argv, char **envp)
                 }
                 configure_msg(opts);
                 break;
+            case QEMU_OPTION_dump_vmstate:
+                vmstate_dump_file = fopen(optarg, "w");
+                if (vmstate_dump_file == NULL) {
+                    fprintf(stderr, "open %s: %s\n", optarg, strerror(errno));
+                    exit(1);
+                }
+                break;
             default:
                 os_parse_cmd_args(popt->index, optarg);
             }
@@ -4488,6 +4496,11 @@ int main(int argc, char **argv, char **envp)
     }
 
     qdev_prop_check_global();
+    if (vmstate_dump_file) {
+        /* dump and exit */
+        dump_vmstate_json_to_file(vmstate_dump_file);
+        return 0;
+    }
 
     if (incoming) {
         Error *local_err = NULL;

vmstate.c

@@ -98,7 +98,11 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                     ret = field->info->get(f, addr, size);
 
                 }
+                if (ret >= 0) {
+                    ret = qemu_file_get_error(f);
+                }
                 if (ret < 0) {
+                    qemu_file_set_error(f, ret);
                     trace_vmstate_load_field_error(field->name, ret);
                     return ret;
                 }