Re: [Qemu-devel] [PATCH v4 05/11] suspend: add infrastructure

[Gleb Natapov]

On Thu, Feb 09, 2012 at 06:05:37PM +0100, Gerd Hoffmann wrote:
> This patch adds some infrastructure to handle suspend and resume to
> qemu.  First there are two functions to switch state and second there
> is a suspend notifier:
> 
>  * qemu_system_suspend_request is supposed to be called when the
>    guest asks for being be suspended, for example via ACPI.
> 
>  * qemu_system_wakeup_request is supposed to be called on events
>    which should wake up the guest.
> 
>  * qemu_register_suspend_notifier can be used to register a notifier
>    which will be called when the guest is suspended.  Machine types
>    and device models can hook in there to modify state if needed.
> 
>  * qemu_register_wakeup_notifier can be used to register a notifier
>    which will be called when the guest is woken up.  Machine types
>    and device models can hook in there to modify state if needed.
> 
>  * qemu_system_wakeup_enable can be used to enable/disable wakeup
>    events.
> 
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  sysemu.h |    9 +++++++++
>  vl.c     |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+), 0 deletions(-)
> 
> diff --git a/sysemu.h b/sysemu.h
> index 9d5ce33..af73813 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -38,7 +38,16 @@ void vm_start(void);
>  void vm_stop(RunState state);
>  void vm_stop_force_state(RunState state);
>  
> +typedef enum WakeupReason {
> +    QEMU_WAKEUP_REASON_OTHER = 0,
> +} WakeupReason;
> +
>  void qemu_system_reset_request(void);
> +void qemu_system_suspend_request(void);
> +void qemu_register_suspend_notifier(Notifier *notifier);
> +void qemu_system_wakeup_request(WakeupReason reason);
> +void qemu_system_wakeup_enable(WakeupReason reason, bool enabled);
> +void qemu_register_wakeup_notifier(Notifier *notifier);
>  void qemu_system_shutdown_request(void);
>  void qemu_system_powerdown_request(void);
>  void qemu_system_debug_request(void);
> diff --git a/vl.c b/vl.c
> index 63dd725..5095e06 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1283,6 +1283,12 @@ static int shutdown_requested, shutdown_signal = -1;
>  static pid_t shutdown_pid;
>  static int powerdown_requested;
>  static int debug_requested;
> +static bool is_suspended;
> +static NotifierList suspend_notifiers =
> +    NOTIFIER_LIST_INITIALIZER(suspend_notifiers);
> +static NotifierList wakeup_notifiers =
> +    NOTIFIER_LIST_INITIALIZER(wakeup_notifiers);
> +static uint32_t wakeup_reason_mask = ~0;
>  static RunState vmstop_requested = RUN_STATE_MAX;
>  
>  int qemu_shutdown_requested_get(void)
> @@ -1398,6 +1404,49 @@ void qemu_system_reset_request(void)
>      qemu_notify_event();
>  }
>  
> +void qemu_system_suspend_request(void)
> +{
> +    if (is_suspended) {
> +        return;
> +    }
> +    cpu_stop_current();
> +    notifier_list_notify(&suspend_notifiers, NULL);
> +    is_suspended = true;
> +}
> +
Shouldn't we stop the whole VM at some point, not only vcpu that
does ACPI IO? May be I missed where it is done in the patch series.

> +void qemu_register_suspend_notifier(Notifier *notifier)
> +{
> +    notifier_list_add(&suspend_notifiers, notifier);
> +}
> +
> +void qemu_system_wakeup_request(WakeupReason reason)
> +{
> +    if (!is_suspended) {
> +        return;
> +    }
> +    if (!(wakeup_reason_mask & (1 << reason))) {
> +        return;
> +    }
> +    notifier_list_notify(&wakeup_notifiers, &reason);
> +    reset_requested = 1;
> +    qemu_notify_event();
> +    is_suspended = false;
> +}
> +
> +void qemu_system_wakeup_enable(WakeupReason reason, bool enabled)
> +{
> +    if (enabled) {
> +        wakeup_reason_mask |= (1 << reason);
> +    } else {
> +        wakeup_reason_mask &= ~(1 << reason);
> +    }
> +}
> +
> +void qemu_register_wakeup_notifier(Notifier *notifier)
> +{
> +    notifier_list_add(&wakeup_notifiers, notifier);
> +}
> +
>  void qemu_system_killed(int signal, pid_t pid)
>  {
>      shutdown_signal = signal;
> -- 
> 1.7.1

--
                        Gleb.