Re: [Qemu-devel] [PATCH v2 3/7] s390x: add css_migration_enabled to machine class

[Cornelia Huck]

On Mon, 29 May 2017 15:55:16 +0200
Halil Pasic <address@hidden> wrote:

> Currently the migration of the channel subsystem (css) is only partial
> and is done by the virtio ccw proxies -- the only migratable  css devices

extra blank ---------------------------------------------------^

> existing at the moment.
> 
> With the current work on emulated and passthrough devices we need to
> decouple the migration of the channel subsystem state from virtio ccw,
> and have a separate section for it. A new section  however necessarily
> breaks the migration compatibility.
> 
> So let us introduce a switch at the machine class, and put it in 'off'
> state for now. We will turn the switch 'on' for future machines once all
> preparations are met. For compatibility  machines the switch will stay
> 'off'.
> 
> Signed-off-by: Halil Pasic <address@hidden>
> ---
>  hw/s390x/s390-virtio-ccw.c         | 13 +++++++++++++
>  include/hw/s390x/s390-virtio-ccw.h |  7 +++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 04148916ed..95256d3982 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -196,6 +196,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void 
> *data)
> 
>      s390mc->ri_allowed = true;
>      s390mc->cpu_model_allowed = true;
> +    s390mc->css_migration_enabled = false; /* TODO: set to true */
>      mc->init = ccw_init;
>      mc->reset = s390_machine_reset;
>      mc->hot_add_cpu = s390_hot_add_cpu;
> @@ -344,6 +345,11 @@ static const TypeInfo ccw_machine_info = {
>      },
>  };
> 
> +bool css_migration_enabled(void)
> +{
> +    return get_machine_class()->css_migration_enabled;
> +}
> +
>  #define DEFINE_CCW_MACHINE(suffix, verstr, latest)                           
>  \
>      static void ccw_machine_##suffix##_class_init(ObjectClass *oc,           
>  \
>                                                    void *data)                
>  \
> @@ -445,6 +451,10 @@ static const TypeInfo ccw_machine_info = {
> 
>  static void ccw_machine_2_10_instance_options(MachineState *machine)
>  {
> +    /*
> +     * TODO Once preparations are done register vmstate for the css if
> +     * css_migration_enabled().
> +     */
>  }
> 
>  static void ccw_machine_2_10_class_options(MachineClass *mc)
> @@ -459,8 +469,11 @@ static void 
> ccw_machine_2_9_instance_options(MachineState *machine)
> 
>  static void ccw_machine_2_9_class_options(MachineClass *mc)
>  {
> +    S390CcwMachineClass *s390mc = S390_MACHINE_CLASS(mc);
> +
>      ccw_machine_2_10_class_options(mc);
>      SET_MACHINE_COMPAT(mc, CCW_COMPAT_2_9);
> +    s390mc->css_migration_enabled = false;
>  }
>  DEFINE_CCW_MACHINE(2_9, "2.9", false);
> 
> diff --git a/include/hw/s390x/s390-virtio-ccw.h 
> b/include/hw/s390x/s390-virtio-ccw.h
> index 7b8a3e4d74..e9c4f4182b 100644
> --- a/include/hw/s390x/s390-virtio-ccw.h
> +++ b/include/hw/s390x/s390-virtio-ccw.h
> @@ -38,6 +38,7 @@ typedef struct S390CcwMachineClass {
>      /*< public >*/
>      bool ri_allowed;
>      bool cpu_model_allowed;
> +    bool css_migration_enabled;
>  } S390CcwMachineClass;
> 
>  /* runtime-instrumentation allowed by the machine */
> @@ -45,4 +46,10 @@ bool ri_allowed(void);
>  /* cpu model allowed by the machine */
>  bool cpu_model_allowed(void);
> 
> +/**
> + * Returns true if (vmstate based) migration of the channel subsystem
> + * is enabled, false if it is disabled.
> + */
> +bool css_migration_enabled(void);
> +
>  #endif

Acked-by: Cornelia Huck <address@hidden>