Re: [Qemu-devel] [PATCH v5 02/10] accel: introduce AccelClass.global_props

[Eduardo Habkost <ehabkost@redhat.com>]

On Fri, Jun 23, 2017 at 12:46:38PM +0800, Peter Xu wrote:
> Introduce this new field for the accelerator classes so that each
> specific accelerator in the future can register its own global
> properties to be used further by the system. It works just like how the
> old machine compatible properties do, but only tailored for
> accelerators.
> 
> Introduce register_compat_props_array() for it. Export it so that it may
> be used in other codes as well in the future.
> 
> Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  accel/accel.c                |  6 ++++++
>  hw/core/qdev-properties.c    |  7 +++++++
>  include/hw/qdev-properties.h |  1 +
>  include/sysemu/accel.h       | 10 ++++++++++
>  vl.c                         |  1 +
>  5 files changed, 25 insertions(+)
> 
> diff --git a/accel/accel.c b/accel/accel.c
> index 7c079a5..fa85844 100644
> --- a/accel/accel.c
> +++ b/accel/accel.c
> @@ -120,6 +120,12 @@ void configure_accelerator(MachineState *ms)
>      }
>  }
>  
> +void accel_register_compat_props(AccelState *accel)
> +{
> +    AccelClass *class = ACCEL_GET_CLASS(accel);
> +    register_compat_props_array(class->global_props);
> +}
> +
>  static void register_accel_types(void)
>  {
>      type_register_static(&accel_type);
> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
> index 6ff1ac3..19fa335 100644
> --- a/hw/core/qdev-properties.c
> +++ b/hw/core/qdev-properties.c
> @@ -1060,6 +1060,13 @@ void register_compat_prop(const char *driver,
>      qdev_prop_register_global(p);
>  }
>  
> +void register_compat_props_array(GlobalProperty *prop)

Note for a later: we need to stop reusing struct GlobalProperty here,
because the 'user_provided', 'used', and 'errp' fields are ignored by
register_compat_prop(), but people may believe the are not.

I suggest defining:

  struct GlobalPropertyValue {
      const char *driver, *property, *value;
  };

and use it instead of GlobalProperty for MachineClass::compat_props,
AccelClass::global_props, and register_compat_prop().

> +{
> +    for (; prop && prop->driver; prop++) {
> +        register_compat_prop(prop->driver, prop->property, prop->value);
> +    }
> +}
> +
>  void qdev_prop_register_global_list(GlobalProperty *props)
>  {
>      int i;
> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> index 1722ca4..2bac6a0 100644
> --- a/include/hw/qdev-properties.h
> +++ b/include/hw/qdev-properties.h
> @@ -203,6 +203,7 @@ void error_set_from_qdev_prop_error(Error **errp, int ret, DeviceState *dev,
>  
>  void register_compat_prop(const char *driver, const char *property,
>                            const char *value);

I suggest documenting here that this function will call
register_compat_prop(), so it will register internal (not user-provided)
global properties.

> +void register_compat_props_array(GlobalProperty *prop);
>  
>  /**
>   * qdev_property_add_static:
> diff --git a/include/sysemu/accel.h b/include/sysemu/accel.h
> index 15944c1..effcd7f 100644
> --- a/include/sysemu/accel.h
> +++ b/include/sysemu/accel.h
> @@ -24,6 +24,7 @@
>  #define HW_ACCEL_H
>  
>  #include "qom/object.h"
> +#include "hw/qdev-properties.h"
>  
>  typedef struct AccelState {
>      /*< private >*/
> @@ -40,6 +41,13 @@ typedef struct AccelClass {
>      int (*available)(void);
>      int (*init_machine)(MachineState *ms);
>      bool *allowed;
> +    /*
> +     * Array of global properties that would be applied when specific
> +     * accelerator is chosen. It works just like
> +     * MachineClass.compat_props but it's for accelerators not
> +     * machines.

I suggest adding this:

"Accelerator-provided global properties may be overridden by
machine-type compat_props or user-provided global properties."

> +     */
> +    GlobalProperty *global_props;
>  } AccelClass;
>  
>  #define TYPE_ACCEL "accel"
> @@ -57,5 +65,7 @@ typedef struct AccelClass {
>  extern int tcg_tb_size;
>  
>  void configure_accelerator(MachineState *ms);
> +/* Register accelerator specific global properties */
> +void accel_register_compat_props(AccelState *accel);
>  
>  #endif
> diff --git a/vl.c b/vl.c
> index 59fea15..4452d7a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4571,6 +4571,7 @@ int main(int argc, char **argv, char **envp)
>              exit (i == 1 ? 1 : 0);
>      }
>  
> +    accel_register_compat_props(current_machine->accelerator);
>      machine_register_compat_props(current_machine);
>  
>      qemu_opts_foreach(qemu_find_opts("global"),
> -- 
> 2.7.4
> 
> 

-- 
Eduardo