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authorAmit Shah <amit.shah@redhat.com>2014-06-20 18:56:08 +0530
committerJuan Quintela <quintela@redhat.com>2014-06-23 19:14:50 +0200
commitabfd9ce341ec66eb2e63756b9da43f77c054788e (patch)
tree025a056ec9e74179c8b4ca4971b30cc06c261281
parente325b49a320b493cc5d69e263751ff716dc458fe (diff)
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migration: dump vmstate info as a json file for static analysis
This commit adds a new command, '-dump-vmstate', that takes a filename as an argument. When executed, QEMU will dump the vmstate information for the machine type it's invoked with to the file, and quit. The JSON-format output can then be used to compare the vmstate info for different QEMU versions, specifically to test whether live migration would break due to changes in the vmstate data. A Python script that compares the output of such JSON dumps is included in the following commit. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
-rw-r--r--include/migration/vmstate.h2
-rw-r--r--qemu-options.hx14
-rw-r--r--savevm.c139
-rw-r--r--vl.c13
4 files changed, 168 insertions, 0 deletions
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 799d2d0..71a8a95 100644
--- a/include/migration/vmstate.h
+++ b/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
diff --git a/qemu-options.hx b/qemu-options.hx
index ca75760..ff76ad4 100644
--- a/qemu-options.hx
+++ b/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
diff --git a/savevm.c b/savevm.c
index 6cbdaac..ba900d3 100644
--- a/savevm.c
+++ b/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;
diff --git a/vl.c b/vl.c
index ab8f152..3288755 100644
--- a/vl.c
+++ b/vl.c
@@ -2935,6 +2935,7 @@ 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]);
@@ -3944,6 +3945,13 @@ 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);
}
@@ -4495,6 +4503,11 @@ 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;