(Cc'ing Markus for a QMP related question.)
On Fri, 14 Oct 2022 at 03:17, Jason A. Donenfeld <[email protected]> wrote:
>
> Snapshot loading only expects to call deterministic handlers, not
> non-deterministic ones. So introduce a way of registering handlers that
> won't be called when reseting for snapshots.
>
> Signed-off-by: Jason A. Donenfeld <[email protected]>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 48e85c052c..a0cdb714f7 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -3058,7 +3058,7 @@ bool load_snapshot(const char *name, const char
> *vmstate,
> goto err_drain;
> }
>
> - qemu_system_reset(SHUTDOWN_CAUSE_NONE);
> + qemu_system_reset(SHUTDOWN_CAUSE_SNAPSHOT_LOAD);
> mis->from_src_file = f;
>
> if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
> diff --git a/qapi/run-state.json b/qapi/run-state.json
> index 9273ea6516..74ed0ac93c 100644
> --- a/qapi/run-state.json
> +++ b/qapi/run-state.json
> @@ -86,12 +86,14 @@
> # ignores --no-reboot. This is useful for sanitizing
> # hypercalls on s390 that are used during kexec/kdump/boot
> #
> +# @snapshot-load: A snapshot is being loaded by the record & replay
> subsystem.
> +#
> ##
> { 'enum': 'ShutdownCause',
> # Beware, shutdown_caused_by_guest() depends on enumeration order
> 'data': [ 'none', 'host-error', 'host-qmp-quit', 'host-qmp-system-reset',
> 'host-signal', 'host-ui', 'guest-shutdown', 'guest-reset',
> - 'guest-panic', 'subsystem-reset'] }
> + 'guest-panic', 'subsystem-reset', 'snapshot-load'] }
Markus: do we need to mark new enum values with some kind of "since n.n"
version info ?
> ##
> # @StatusInfo:
> diff --git a/softmmu/runstate.c b/softmmu/runstate.c
> index 1e68680b9d..03e1ee3a8a 100644
> --- a/softmmu/runstate.c
> +++ b/softmmu/runstate.c
> @@ -441,9 +441,9 @@ void qemu_system_reset(ShutdownCause reason)
> cpu_synchronize_all_states();
>
> if (mc && mc->reset) {
> - mc->reset(current_machine);
> + mc->reset(current_machine, reason);
> } else {
> - qemu_devices_reset();
> + qemu_devices_reset(reason);
> }
> if (reason && reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {
> qapi_event_send_reset(shutdown_caused_by_guest(reason), reason);
This change means that resets on snapshot-load, which previously
did not result in sending a QMP event, will now start to do so
with this new ShutdownCause type. I don't think we want that
change in behaviour.
(Also, as per the 'Beware' comment in run-state.json, we will
claim this to be a 'caused by guest' reset, which doesn't seem
right. If we suppress the sending the event that is moot, though.)
Markus: if we add a new value to the ShutdownCause enumeration,
how annoying is it if we decide we don't want it later? I guess
we can just leave it in the enum unused... (In this case we're
using it for purely internal purposes and it won't ever actually
wind up in any QMP events.)
thanks
-- PMM
