Re: [Qemu-devel] [PATCH v2 1/3] machine: Add wakeup method to MachineClass

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jul 22, 2019 at 03:32:13PM +1000, Nicholas Piggin wrote:
> Waking from suspend is not logically a machine reset on all machines,
> particularly in the paravirtualized case rather than hardware
> emulated. The ppc spapr machine for example just invokes hypervisor
> to suspend, and expects that call to return with the machine in the
> same state (modulo some possible migration and reconfiguration
> details).
> 
> Implement a machine ->wakeup method and use that if it exists.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  include/hw/boards.h |  1 +
>  vl.c                | 18 +++++++++++++++++-
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index a71d1a53a5..915ac3352b 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -180,6 +180,7 @@ struct MachineClass {
>  
>      void (*init)(MachineState *state);
>      void (*reset)(MachineState *state);
> +    void (*wakeup)(MachineState *state);
>      void (*hot_add_cpu)(MachineState *state, const int64_t id, Error **errp);
>      int (*kvm_type)(MachineState *machine, const char *arg);
>      void (*smp_parse)(MachineState *ms, QemuOpts *opts);
> diff --git a/vl.c b/vl.c
> index cefe5a3968..45ea034410 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1556,6 +1556,22 @@ void qemu_system_reset(ShutdownCause reason)
>      cpu_synchronize_all_post_reset();
>  }
>  
> +/*
> + * Wake the VM after suspend.
> + */
> +static void qemu_system_wakeup(void)
> +{
> +    MachineClass *mc;
> +
> +    mc = current_machine ? MACHINE_GET_CLASS(current_machine) : NULL;
> +
> +    if (mc && mc->wakeup) {
> +        mc->wakeup(current_machine);
> +    } else {
> +        qemu_system_reset(SHUTDOWN_CAUSE_NONE);
> +    }
> +}
> +
>  void qemu_system_guest_panicked(GuestPanicInformation *info)
>  {
>      qemu_log_mask(LOG_GUEST_ERROR, "Guest crashed");
> @@ -1764,7 +1780,7 @@ static bool main_loop_should_exit(void)
>      }
>      if (qemu_wakeup_requested()) {
>          pause_all_vcpus();
> -        qemu_system_reset(SHUTDOWN_CAUSE_NONE);
> +        qemu_system_wakeup();
>          notifier_list_notify(&wakeup_notifiers, &wakeup_reason);
>          wakeup_reason = QEMU_WAKEUP_REASON_NONE;
>          resume_all_vcpus();

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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