From abfd9ce341ec66eb2e63756b9da43f77c054788e Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Fri, 20 Jun 2014 18:56:08 +0530 Subject: [PATCH] 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 Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/migration/vmstate.h | 2 + qemu-options.hx | 14 ++++ savevm.c | 139 ++++++++++++++++++++++++++++++++++++ vl.c | 13 ++++ 4 files changed, 168 insertions(+) diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index 799d2d0f03..71a8a95641 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 ca75760b27..ff76ad4830 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 \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 6cbdaacacd..ba900d304b 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 ab8f15243b..32887559be 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;