[26/36] remove preconfig state

The preconfig state is only used if -incoming is not specified, which
makes the RunState state machine more tricky than it need be.  However
there is already an equivalent condition which works even with -incoming,
namely qdev_hotplug.  Use it instead of a separate runstate.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/core/machine-qmp-cmds.c    |  5 ++---
 include/qapi/qmp/dispatch.h   |  1 +
 monitor/hmp.c                 |  7 ++++---
 monitor/qmp-cmds.c            |  5 ++---
 qapi/qmp-dispatch.c           |  5 +----
 qapi/run-state.json           |  5 +----
 softmmu/qdev-monitor.c        | 12 ++++++++++++
 softmmu/vl.c                  | 13 ++-----------
 stubs/meson.build             |  1 +
 stubs/qmp-command-available.c |  7 +++++++
 tests/qtest/qmp-test.c        |  2 +-
 11 files changed, 34 insertions(+), 29 deletions(-)
 create mode 100644 stubs/qmp-command-available.c

On Mon, 23 Nov 2020 09:14:25 -0500
Paolo Bonzini <pbonzini@redhat.com> wrote:

> The preconfig state is only used if -incoming is not specified, which
> makes the RunState state machine more tricky than it need be.  However
> there is already an equivalent condition which works even with -incoming,
> namely qdev_hotplug.  Use it instead of a separate runstate.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/core/machine-qmp-cmds.c    |  5 ++---
>  include/qapi/qmp/dispatch.h   |  1 +
>  monitor/hmp.c                 |  7 ++++---
>  monitor/qmp-cmds.c            |  5 ++---
>  qapi/qmp-dispatch.c           |  5 +----
>  qapi/run-state.json           |  5 +----
>  softmmu/qdev-monitor.c        | 12 ++++++++++++
>  softmmu/vl.c                  | 13 ++-----------
>  stubs/meson.build             |  1 +
>  stubs/qmp-command-available.c |  7 +++++++
>  tests/qtest/qmp-test.c        |  2 +-
>  11 files changed, 34 insertions(+), 29 deletions(-)
>  create mode 100644 stubs/qmp-command-available.c
> 
> diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
> index 5362c80a18..cb9387c5f5 100644
> --- a/hw/core/machine-qmp-cmds.c
> +++ b/hw/core/machine-qmp-cmds.c
> @@ -286,9 +286,8 @@ HotpluggableCPUList *qmp_query_hotpluggable_cpus(Error **errp)
>  
>  void qmp_set_numa_node(NumaOptions *cmd, Error **errp)
>  {
> -    if (!runstate_check(RUN_STATE_PRECONFIG)) {
> -        error_setg(errp, "The command is permitted only in '%s' state",
> -                   RunState_str(RUN_STATE_PRECONFIG));
> +    if (qdev_hotplug) {

that would work only as long as qemu_init_board() hasn't been called,
and fall apart as soon as we permit creating cold-pluged devices
(qemu_create_cli_devices()) at preconfig stage.

for qmp_set_numa_node() the better fit would something like
  if(is_board_created)
     error_out
so it won't break silently when we start extending list of
commands allowed at preconfig time.

> +         error_setg(errp, "The command is permitted only before the machine has been created");
>           return;
>      }
>  
> diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
> index af8d96c570..1486cac3ef 100644
> --- a/include/qapi/qmp/dispatch.h
> +++ b/include/qapi/qmp/dispatch.h
> @@ -48,6 +48,7 @@ void qmp_disable_command(QmpCommandList *cmds, const char *name);
>  void qmp_enable_command(QmpCommandList *cmds, const char *name);
>  
>  bool qmp_command_is_enabled(const QmpCommand *cmd);
> +bool qmp_command_available(const QmpCommand *cmd, Error **errp);
>  const char *qmp_command_name(const QmpCommand *cmd);
>  bool qmp_has_success_response(const QmpCommand *cmd);
>  QDict *qmp_error_response(Error *err);
> diff --git a/monitor/hmp.c b/monitor/hmp.c
> index d40f4f4391..f2fe192d69 100644
> --- a/monitor/hmp.c
> +++ b/monitor/hmp.c
> @@ -24,6 +24,7 @@
>  
>  #include "qemu/osdep.h"
>  #include <dirent.h>
> +#include "hw/qdev-core.h"
>  #include "monitor-internal.h"
>  #include "qapi/error.h"
>  #include "qapi/qmp/qdict.h"
> @@ -215,7 +216,7 @@ static bool cmd_can_preconfig(const HMPCommand *cmd)
>  
>  static bool cmd_available(const HMPCommand *cmd)
>  {
> -    return !runstate_check(RUN_STATE_PRECONFIG) || cmd_can_preconfig(cmd);
> +    return qdev_hotplug || cmd_can_preconfig(cmd);
>  }
>  
>  static void help_cmd_dump_one(Monitor *mon,
> @@ -658,8 +659,8 @@ static const HMPCommand *monitor_parse_command(MonitorHMP *hmp_mon,
>          return NULL;
>      }
>      if (!cmd_available(cmd)) {
> -        monitor_printf(mon, "Command '%.*s' not available with -preconfig "
> -                            "until after exit_preconfig.\n",
> +        monitor_printf(mon, "Command '%.*s' not available "
> +                            "until machine initialization has completed.\n",
>                         (int)(p - cmdp_start), cmdp_start);
>          return NULL;
>      }
> diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
> index 6299c0c8c7..501a3024c7 100644
> --- a/monitor/qmp-cmds.c
> +++ b/monitor/qmp-cmds.c
> @@ -104,9 +104,8 @@ void qmp_system_powerdown(Error **errp)
>  
>  void qmp_x_exit_preconfig(Error **errp)
>  {
> -    if (!runstate_check(RUN_STATE_PRECONFIG)) {
> -        error_setg(errp, "The command is permitted only in '%s' state",
> -                   RunState_str(RUN_STATE_PRECONFIG));
> +    if (qdev_hotplug) {
> +        error_setg(errp, "The command is permitted only before machine initialization");
>          return;
>      }
>      qemu_exit_preconfig_request();
> diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
> index 9a2d7dd29a..0a2b20a4e4 100644
> --- a/qapi/qmp-dispatch.c
> +++ b/qapi/qmp-dispatch.c
> @@ -167,10 +167,7 @@ QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request,
>          goto out;
>      }
>  
> -    if (runstate_check(RUN_STATE_PRECONFIG) &&
> -        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
> -        error_setg(&err, "The command '%s' isn't permitted in '%s' state",
> -                   cmd->name, RunState_str(RUN_STATE_PRECONFIG));
> +    if (!qmp_command_available(cmd, &err)) {
>          goto out;
>      }
>  
> diff --git a/qapi/run-state.json b/qapi/run-state.json
> index 964c8ef391..38194b0e44 100644
> --- a/qapi/run-state.json
> +++ b/qapi/run-state.json
> @@ -50,15 +50,12 @@
>  # @colo: guest is paused to save/restore VM state under colo checkpoint,
>  #        VM can not get into this state unless colo capability is enabled
>  #        for migration. (since 2.8)
> -# @preconfig: QEMU is paused before board specific init callback is executed.
> -#             The state is reachable only if the --preconfig CLI option is used.
> -#             (Since 3.0)
>  ##
>  { 'enum': 'RunState',
>    'data': [ 'debug', 'inmigrate', 'internal-error', 'io-error', 'paused',
>              'postmigrate', 'prelaunch', 'finish-migrate', 'restore-vm',
>              'running', 'save-vm', 'shutdown', 'suspended', 'watchdog',
> -            'guest-panicked', 'colo', 'preconfig' ] }
> +            'guest-panicked', 'colo' ] }
>  
>  ##
>  # @ShutdownCause:
> diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
> index d060e765da..e967d13bd0 100644
> --- a/softmmu/qdev-monitor.c
> +++ b/softmmu/qdev-monitor.c
> @@ -25,6 +25,7 @@
>  #include "sysemu/arch_init.h"
>  #include "qapi/error.h"
>  #include "qapi/qapi-commands-qdev.h"
> +#include "qapi/qmp/dispatch.h"
>  #include "qapi/qmp/qdict.h"
>  #include "qapi/qmp/qerror.h"
>  #include "qemu/config-file.h"
> @@ -997,3 +998,14 @@ int qemu_global_option(const char *str)
>  
>      return 0;
>  }
> +
> +bool qmp_command_available(const QmpCommand *cmd, Error **errp)
> +{
> +    if (!qdev_hotplug &&
> +        !(cmd->options & QCO_ALLOW_PRECONFIG)) {
> +        error_setg(errp, "The command '%s' is permitted only after machine initialization has completed",
> +                   cmd->name);
> +        return false;
> +    }
> +    return true;
> +}
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index ecfe16c4c4..95c62bdad4 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -573,7 +573,7 @@ static int default_driver_check(void *opaque, QemuOpts *opts, Error **errp)
>  /***********************************************************/
>  /* QEMU state */
>  
> -static RunState current_run_state = RUN_STATE_PRECONFIG;
> +static RunState current_run_state = RUN_STATE_PRELAUNCH;
>  
>  /* We use RUN_STATE__MAX but any invalid value will do */
>  static RunState vmstop_requested = RUN_STATE__MAX;
> @@ -585,13 +585,7 @@ typedef struct {
>  } RunStateTransition;
>  
>  static const RunStateTransition runstate_transitions_def[] = {
> -    /*     from      ->     to      */
> -    { RUN_STATE_PRECONFIG, RUN_STATE_PRELAUNCH },
> -      /* Early switch to inmigrate state to allow  -incoming CLI option work
> -       * as it used to. TODO: delay actual switching to inmigrate state to
> -       * the point after machine is built and remove this hack.
> -       */
> -    { RUN_STATE_PRECONFIG, RUN_STATE_INMIGRATE },
> +    { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
>  
>      { RUN_STATE_DEBUG, RUN_STATE_RUNNING },
>      { RUN_STATE_DEBUG, RUN_STATE_FINISH_MIGRATE },
> @@ -1633,9 +1627,6 @@ static bool main_loop_should_exit(void)
>      ShutdownCause request;
>  
>      if (preconfig_exit_requested) {
> -        if (runstate_check(RUN_STATE_PRECONFIG)) {
> -            runstate_set(RUN_STATE_PRELAUNCH);
> -        }
>          preconfig_exit_requested = false;
>          return true;
>      }
> diff --git a/stubs/meson.build b/stubs/meson.build
> index 82b7ba60ab..cc56c83063 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -29,6 +29,7 @@ stub_ss.add(files('pci-bus.c'))
>  stub_ss.add(files('pci-host-piix.c'))
>  stub_ss.add(files('qemu-timer-notify-cb.c'))
>  stub_ss.add(files('qmp_memory_device.c'))
> +stub_ss.add(files('qmp-command-available.c'))
>  stub_ss.add(files('qtest.c'))
>  stub_ss.add(files('ram-block.c'))
>  stub_ss.add(files('ramfb.c'))
> diff --git a/stubs/qmp-command-available.c b/stubs/qmp-command-available.c
> new file mode 100644
> index 0000000000..46540af7bf
> --- /dev/null
> +++ b/stubs/qmp-command-available.c
> @@ -0,0 +1,7 @@
> +#include "qemu/osdep.h"
> +#include "qapi/qmp/dispatch.h"
> +
> +bool qmp_command_available(const QmpCommand *cmd, Error **errp)
> +{
> +    return true;
> +}
> diff --git a/tests/qtest/qmp-test.c b/tests/qtest/qmp-test.c
> index eb1cd8abb8..11614bf63f 100644
> --- a/tests/qtest/qmp-test.c
> +++ b/tests/qtest/qmp-test.c
> @@ -295,7 +295,7 @@ static void test_qmp_preconfig(void)
>      rsp = qtest_qmp(qs, "{ 'execute': 'query-status' }");
>      ret = qdict_get_qdict(rsp, "return");
>      g_assert(ret);
> -    g_assert_cmpstr(qdict_get_try_str(ret, "status"), ==, "preconfig");
> +    g_assert_cmpstr(qdict_get_try_str(ret, "status"), ==, "prelaunch");
>      qobject_unref(rsp);
>  
>      /* exit preconfig state */

On 26/11/20 19:55, Igor Mammedov wrote:
> On Mon, 23 Nov 2020 09:14:25 -0500
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> The preconfig state is only used if -incoming is not specified, which
>> makes the RunState state machine more tricky than it need be.  However
>> there is already an equivalent condition which works even with -incoming,
>> namely qdev_hotplug.  Use it instead of a separate runstate.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>   hw/core/machine-qmp-cmds.c    |  5 ++---
>>   include/qapi/qmp/dispatch.h   |  1 +
>>   monitor/hmp.c                 |  7 ++++---
>>   monitor/qmp-cmds.c            |  5 ++---
>>   qapi/qmp-dispatch.c           |  5 +----
>>   qapi/run-state.json           |  5 +----
>>   softmmu/qdev-monitor.c        | 12 ++++++++++++
>>   softmmu/vl.c                  | 13 ++-----------
>>   stubs/meson.build             |  1 +
>>   stubs/qmp-command-available.c |  7 +++++++
>>   tests/qtest/qmp-test.c        |  2 +-
>>   11 files changed, 34 insertions(+), 29 deletions(-)
>>   create mode 100644 stubs/qmp-command-available.c
>>
>> diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
>> index 5362c80a18..cb9387c5f5 100644
>> --- a/hw/core/machine-qmp-cmds.c
>> +++ b/hw/core/machine-qmp-cmds.c
>> @@ -286,9 +286,8 @@ HotpluggableCPUList *qmp_query_hotpluggable_cpus(Error **errp)
>>   
>>   void qmp_set_numa_node(NumaOptions *cmd, Error **errp)
>>   {
>> -    if (!runstate_check(RUN_STATE_PRECONFIG)) {
>> -        error_setg(errp, "The command is permitted only in '%s' state",
>> -                   RunState_str(RUN_STATE_PRECONFIG));
>> +    if (qdev_hotplug) {
> 
> that would work only as long as qemu_init_board() hasn't been called,
> and fall apart as soon as we permit creating cold-pluged devices
> (qemu_create_cli_devices()) at preconfig stage.
> 
> for qmp_set_numa_node() the better fit would something like
>    if(is_board_created)
>       error_out
> so it won't break silently when we start extending list of
> commands allowed at preconfig time.
> 
>> +         error_setg(errp, "The command is permitted only before the machine has been created");
>>            return;
>>       }

I don't understand...  qdev_hotplug is a bad name for is_board_created, 
it is set by qdev_machine_creation_done which is called after preconfig 
is left.  As of this patch that happens after the early 
qemu_main_loop(); the next patch moves it to qmp_x_exit_preconfig.

Cold-plugged devices would (by definition) be created while qdev_hotplug 
is false.  But before we get there, I will have replaced the two states 
permitted by qdev_hotplug with five separate phases (PHASE_NO_MACHINE, 
PHASE_MACHINE_CREATED, PHASE_ACCEL_CREATED, PHASE_MACHINE_INITIALIZED, 
PHASE_MACHINE_READY) to clarify the QMP command implementation and to 
assert that various functions are called in the right phase.

Thanks,

Paolo

On Fri, 27 Nov 2020 06:19:51 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 26/11/20 19:55, Igor Mammedov wrote:
> > On Mon, 23 Nov 2020 09:14:25 -0500
> > Paolo Bonzini <pbonzini@redhat.com> wrote:
> >   
> >> The preconfig state is only used if -incoming is not specified, which
> >> makes the RunState state machine more tricky than it need be.  However
> >> there is already an equivalent condition which works even with -incoming,
> >> namely qdev_hotplug.  Use it instead of a separate runstate.
> >>
> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >> ---
> >>   hw/core/machine-qmp-cmds.c    |  5 ++---
> >>   include/qapi/qmp/dispatch.h   |  1 +
> >>   monitor/hmp.c                 |  7 ++++---
> >>   monitor/qmp-cmds.c            |  5 ++---
> >>   qapi/qmp-dispatch.c           |  5 +----
> >>   qapi/run-state.json           |  5 +----
> >>   softmmu/qdev-monitor.c        | 12 ++++++++++++
> >>   softmmu/vl.c                  | 13 ++-----------
> >>   stubs/meson.build             |  1 +
> >>   stubs/qmp-command-available.c |  7 +++++++
> >>   tests/qtest/qmp-test.c        |  2 +-
> >>   11 files changed, 34 insertions(+), 29 deletions(-)
> >>   create mode 100644 stubs/qmp-command-available.c
> >>
> >> diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
> >> index 5362c80a18..cb9387c5f5 100644
> >> --- a/hw/core/machine-qmp-cmds.c
> >> +++ b/hw/core/machine-qmp-cmds.c
> >> @@ -286,9 +286,8 @@ HotpluggableCPUList *qmp_query_hotpluggable_cpus(Error **errp)
> >>   
> >>   void qmp_set_numa_node(NumaOptions *cmd, Error **errp)
> >>   {
> >> -    if (!runstate_check(RUN_STATE_PRECONFIG)) {
> >> -        error_setg(errp, "The command is permitted only in '%s' state",
> >> -                   RunState_str(RUN_STATE_PRECONFIG));
> >> +    if (qdev_hotplug) {  
> > 
> > that would work only as long as qemu_init_board() hasn't been called,
> > and fall apart as soon as we permit creating cold-pluged devices
> > (qemu_create_cli_devices()) at preconfig stage.
> > 
> > for qmp_set_numa_node() the better fit would something like
> >    if(is_board_created)
> >       error_out
> > so it won't break silently when we start extending list of
> > commands allowed at preconfig time.
> >   
> >> +         error_setg(errp, "The command is permitted only before the machine has been created");
> >>            return;
> >>       }  
> 
> I don't understand...  qdev_hotplug is a bad name for is_board_created, 
> it is set by qdev_machine_creation_done which is called after preconfig 
> is left.  As of this patch that happens after the early 
> qemu_main_loop(); the next patch moves it to qmp_x_exit_preconfig.
it works in context of this series since

  +    qemu_init_board();
  +    qemu_create_cli_devices();
  +    qemu_machine_creation_done();

are called within the same command qmp_x_exit_preconfig, 
if preconfig is enabled we happen to call qmp_set_numa_node()
and if (qdev_hotplug) {error} work as expected, since qemu_init_board()
hasn't been called yet.

but I'm thinking about what happens beyond this series, when we start
splitting qmp_x_exit_preconfig() after this series on separate stages.

By using qdev_hotplug here, we practically loose dependency tracking
on qemu_init_board() not being yet called. And if later we forget that,
then it would allow to call qmp_set_numa_node() after qemu_init_board()
but before qemu_machine_creation_done()

So for this intermediate stage, instead of abusing qdev_hotplug adding
a temporary is_board_created might be used. And when we introduce
new phases you've described below, is_board_created could be replaced
with appropriate phase check.


> Cold-plugged devices would (by definition) be created while qdev_hotplug 
> is false.  But before we get there, I will have replaced the two states 
> permitted by qdev_hotplug with five separate phases (PHASE_NO_MACHINE, 
> PHASE_MACHINE_CREATED, PHASE_ACCEL_CREATED, PHASE_MACHINE_INITIALIZED, 
> PHASE_MACHINE_READY) to clarify the QMP command implementation and to 
> assert that various functions are called in the right phase.
> 
> Thanks,
> 
> Paolo
>

On 27/11/20 11:50, Igor Mammedov wrote:
> it works in context of this series since
> 
>    +    qemu_init_board();
>    +    qemu_create_cli_devices();
>    +    qemu_machine_creation_done();
> 
> are called within the same command qmp_x_exit_preconfig,
> if preconfig is enabled we happen to call qmp_set_numa_node()
> and if (qdev_hotplug) {error} work as expected, since qemu_init_board()
> hasn't been called yet.
> 
> but I'm thinking about what happens beyond this series, when we start
> splitting qmp_x_exit_preconfig() after this series on separate stages.

Ok, so that's the source of confusion.  I don't think anymore that 
x-exit-preconfig should be split in separate stages; I'm not looking 
anymore at being able to do device-add from "qemu-system-x86_64 
-preconfig".  Instead, I'm looking at having a completely separate 
executable for QMP-only machine creation, which would not use vl.c 
command line parsing at all.

For this reason I've left MachinePhase to a separate series, which I 
still plan for 6.0.  But I will add it here instead.

FWIW I intend to have four parts: 1) this 2) QemuOpts->keyval switch for 
-object/-M/-accel 3) making Machine's memdev property a 
link<memory-backend> 4) making -smp/-boot/-m sugar for non-scalar 
properties of Machine.  I'll definitely need your review on part 3 too!

Thanks,

Paolo

> By using qdev_hotplug here, we practically loose dependency tracking
> on qemu_init_board() not being yet called. And if later we forget that,
> then it would allow to call qmp_set_numa_node() after qemu_init_board()
> but before qemu_machine_creation_done()
> 
> So for this intermediate stage, instead of abusing qdev_hotplug adding
> a temporary is_board_created might be used. And when we introduce
> new phases you've described below, is_board_created could be replaced
> with appropriate phase check.

On Fri, 27 Nov 2020 12:50:39 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 27/11/20 11:50, Igor Mammedov wrote:
> > it works in context of this series since
> > 
> >    +    qemu_init_board();
> >    +    qemu_create_cli_devices();
> >    +    qemu_machine_creation_done();
> > 
> > are called within the same command qmp_x_exit_preconfig,
> > if preconfig is enabled we happen to call qmp_set_numa_node()
> > and if (qdev_hotplug) {error} work as expected, since qemu_init_board()
> > hasn't been called yet.
> > 
> > but I'm thinking about what happens beyond this series, when we start
> > splitting qmp_x_exit_preconfig() after this series on separate stages.  
> 
> Ok, so that's the source of confusion.  I don't think anymore that 
> x-exit-preconfig should be split in separate stages; I'm not looking 
> anymore at being able to do device-add from "qemu-system-x86_64 
> -preconfig".  Instead, I'm looking at having a completely separate 
> executable for QMP-only machine creation, which would not use vl.c 
> command line parsing at all.
> 
> For this reason I've left MachinePhase to a separate series, which I 
> still plan for 6.0.  But I will add it here instead.
Assuming that qmp_x_exit_preconfig() won't be split:

 Reviewed-by: Igor Mammedov <imammedo@redhat.com>


> FWIW I intend to have four parts: 1) this 2) QemuOpts->keyval switch for 
> -object/-M/-accel 3) making Machine's memdev property a 
> link<memory-backend> 4) making -smp/-boot/-m sugar for non-scalar 
> properties of Machine.  I'll definitely need your review on part 3 too!

I can review #3, #4 and your ram_size cleanup, which I'm somewhat familiar with.

> 
> Thanks,
> 
> Paolo
> 
> > By using qdev_hotplug here, we practically loose dependency tracking
> > on qemu_init_board() not being yet called. And if later we forget that,
> > then it would allow to call qmp_set_numa_node() after qemu_init_board()
> > but before qemu_machine_creation_done()
> > 
> > So for this intermediate stage, instead of abusing qdev_hotplug adding
> > a temporary is_board_created might be used. And when we introduce
> > new phases you've described below, is_board_created could be replaced
> > with appropriate phase check.  
>