* Amit Shah (amit.s...@redhat.com) wrote:
> This commit adds a new command, '-dump-vmstate', that takes a filename
> as a parameter. 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.
>
> This is based on a version from Andreas Färber posted here:
> https://lists.gnu.org/archive/html/qemu-devel/2013-10/msg03095.html
>
> A Python script that compares the output of such JSON dumps is included
> in the following commit.
>
> Signed-off-by: Amit Shah <amit.s...@redhat.com>
> ---
> include/migration/vmstate.h | 2 +
> qemu-options.hx | 9 +++
> savevm.c | 134
> ++++++++++++++++++++++++++++++++++++++++++++
> vl.c | 14 +++++
> 4 files changed, 159 insertions(+)
>
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index 7e45048..9829c0e 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -778,4 +778,6 @@ void vmstate_register_ram(struct MemoryRegion *memory,
> DeviceState *dev);
> void vmstate_unregister_ram(struct MemoryRegion *memory, DeviceState *dev);
> void vmstate_register_ram_global(struct MemoryRegion *memory);
>
> +void dump_vmstate_json_to_file(FILE *out_fp);
> +
> #endif
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 781af14..d376227 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3146,6 +3146,15 @@ STEXI
> prepend a timestamp to each log message.(default:on)
> ETEXI
>
> +DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
> + "-dump-vmstate <file>\n" "", 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 da8aa24..a4ce279 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"
> @@ -241,6 +242,139 @@ 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)
checkpatch points out that some tabs managed to get into that indent line.
Generally I think this patch is OK and quite useful; two thoughts:
1) I was surprised it dumped every object type, rather than just those
that are instantiated; I think the latter would be more use in some
circumstances, since there's a load of weird and wonderful objects
that exist and are very rarely used.
2) 'fields_exists' is a weird naming to put in the json file - it's
a function pointer for determining if the field is going to be present;
maybe renaming as 'conditional' would make sense.
Dave
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
