Re: [RFC v7 12/22] cpu: Introduce TCGCpuOperations struct

[Philippe Mathieu-Daudé]

On 11/30/20 3:35 AM, Claudio Fontana wrote:
> From: Eduardo Habkost <ehabkost@redhat.com>
> 
> The TCG-specific CPU methods will be moved to a separate struct,
> to make it easier to move accel-specific code outside generic CPU
> code in the future.  Start by moving tcg_initialize().

Good idea! One minor comment below.

> 
> The new CPUClass.tcg_opts field may eventually become a pointer,
> but keep it an embedded struct for now, to make code conversion
> easier.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  MAINTAINERS                     |  1 +
>  cpu.c                           |  2 +-
>  include/hw/core/cpu.h           |  9 ++++++++-
>  include/hw/core/tcg-cpu-ops.h   | 25 +++++++++++++++++++++++++
>  target/alpha/cpu.c              |  2 +-
>  target/arm/cpu.c                |  2 +-
>  target/avr/cpu.c                |  2 +-
>  target/cris/cpu.c               | 12 ++++++------
>  target/hppa/cpu.c               |  2 +-
>  target/i386/tcg-cpu.c           |  2 +-
>  target/lm32/cpu.c               |  2 +-
>  target/m68k/cpu.c               |  2 +-
>  target/microblaze/cpu.c         |  2 +-
>  target/mips/cpu.c               |  2 +-
>  target/moxie/cpu.c              |  2 +-
>  target/nios2/cpu.c              |  2 +-
>  target/openrisc/cpu.c           |  2 +-
>  target/ppc/translate_init.c.inc |  2 +-
>  target/riscv/cpu.c              |  2 +-
>  target/rx/cpu.c                 |  2 +-
>  target/s390x/cpu.c              |  2 +-
>  target/sh4/cpu.c                |  2 +-
>  target/sparc/cpu.c              |  2 +-
>  target/tilegx/cpu.c             |  2 +-
>  target/tricore/cpu.c            |  2 +-
>  target/unicore32/cpu.c          |  2 +-
>  target/xtensa/cpu.c             |  2 +-
>  27 files changed, 63 insertions(+), 30 deletions(-)
>  create mode 100644 include/hw/core/tcg-cpu-ops.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f53f2678d8..d876f504a6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1535,6 +1535,7 @@ F: qapi/machine.json
>  F: qapi/machine-target.json
>  F: include/hw/boards.h
>  F: include/hw/core/cpu.h
> +F: include/hw/core/tcg-cpu-ops.h
>  F: include/hw/cpu/cluster.h
>  F: include/sysemu/numa.h
>  T: git https://github.com/ehabkost/qemu.git machine-next
> diff --git a/cpu.c b/cpu.c
> index 0be5dcb6f3..d02c2a17f1 100644
> --- a/cpu.c
> +++ b/cpu.c
> @@ -180,7 +180,7 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
>  
>      if (tcg_enabled() && !tcg_target_initialized) {
>          tcg_target_initialized = true;
> -        cc->tcg_initialize();
> +        cc->tcg_ops.initialize();
>      }
>      tlb_init(cpu);
>  
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index 3d92c967ff..c93b08a0fb 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -76,6 +76,10 @@ typedef struct CPUWatchpoint CPUWatchpoint;
>  
>  struct TranslationBlock;
>  
> +#ifdef CONFIG_TCG
> +#include "tcg-cpu-ops.h"
> +#endif /* CONFIG_TCG */
> +
>  /**
>   * CPUClass:
>   * @class_by_name: Callback to map -cpu command line model name to an
> @@ -221,12 +225,15 @@ struct CPUClass {
>  
>      void (*disas_set_info)(CPUState *cpu, disassemble_info *info);
>      vaddr (*adjust_watchpoint_address)(CPUState *cpu, vaddr addr, int len);
> -    void (*tcg_initialize)(void);
>  
>      const char *deprecation_note;
>      /* Keep non-pointer data at the end to minimize holes.  */
>      int gdb_num_core_regs;
>      bool gdb_stop_before_watchpoint;
> +
> +#ifdef CONFIG_TCG
> +    TcgCpuOperations tcg_ops;
> +#endif /* CONFIG_TCG */
>  };
>  
>  /*
> diff --git a/include/hw/core/tcg-cpu-ops.h b/include/hw/core/tcg-cpu-ops.h
> new file mode 100644
> index 0000000000..4475ef0996
> --- /dev/null
> +++ b/include/hw/core/tcg-cpu-ops.h
> @@ -0,0 +1,25 @@
> +/*
> + * TCG-Specific operations that are not meaningful for hardware accelerators
> + *
> + * Copyright 2020 SUSE LLC
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef TCG_CPU_OPS_H
> +#define TCG_CPU_OPS_H
> +
> +/**
> + * struct TcgCpuOperations: TCG operations specific to a CPU class
> + */
> +typedef struct TcgCpuOperations {
> +    /**
> +     * @initialize: Initalize TCG state
> +     *
> +     * Called when the first CPU is realized.
> +     */
> +    void (*initialize)(void);
> +} TcgCpuOperations;
> +
> +#endif /* TCG_CPU_OPS_H */
...

> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 07492e9f9a..1fa9382a7c 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -2261,7 +2261,7 @@ static void arm_cpu_class_init(ObjectClass *oc, void 
> *data)
>      cc->gdb_stop_before_watchpoint = true;
>      cc->disas_set_info = arm_disas_set_info;
>  #ifdef CONFIG_TCG
> -    cc->tcg_initialize = arm_translate_init;
> +    cc->tcg_ops.initialize = arm_translate_init;

This one is correctly guarded by '#ifdef CONFIG_TCG'.

For the other targets, can you either place it within
the '#ifdef CONFIG_TCG' block or if there is none, add
one please?

With that change:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Thanks,

Phil.