Re: [PATCH v4 03/28] cpu: Introduce cpu_virtio_is_big_endian()

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 03, 2021 at 10:46:43PM +0100, Philippe Mathieu-Daudé wrote:
> Introduce the cpu_virtio_is_big_endian() generic helper to avoid
> calling CPUClass internal virtio_is_big_endian() one.
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Using virtio in the name here probably because virtio wants this?
That doesn't sound like a good naming strategy, name should
tell us what function does not how it's used.

> ---
>  include/hw/core/cpu.h | 9 +++++++++
>  hw/core/cpu.c         | 8 ++++++--
>  hw/virtio/virtio.c    | 4 +---
>  3 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index 2d43f78819f..b12028c3c03 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -602,6 +602,15 @@ hwaddr cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
>   */
>  int cpu_asidx_from_attrs(CPUState *cpu, MemTxAttrs attrs);
>  
> +/**
> + * cpu_virtio_is_big_endian:
> + * @cpu: CPU
> +
> + * Returns %true if a CPU which supports runtime configurable endianness
> + * is currently big-endian.
> + */
> +bool cpu_virtio_is_big_endian(CPUState *cpu);
> +
>  #endif /* CONFIG_USER_ONLY */
>  
>  /**
> diff --git a/hw/core/cpu.c b/hw/core/cpu.c
> index 4dce35f832f..daaff56a79e 100644
> --- a/hw/core/cpu.c
> +++ b/hw/core/cpu.c
> @@ -218,8 +218,13 @@ static int cpu_common_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg)
>      return 0;
>  }
>  
> -static bool cpu_common_virtio_is_big_endian(CPUState *cpu)
> +bool cpu_virtio_is_big_endian(CPUState *cpu)
>  {
> +    CPUClass *cc = CPU_GET_CLASS(cpu);
> +
> +    if (cc->virtio_is_big_endian) {
> +        return cc->virtio_is_big_endian(cpu);
> +    }
>      return target_words_bigendian();
>  }
>  
> @@ -438,7 +443,6 @@ static void cpu_class_init(ObjectClass *klass, void *data)
>      k->write_elf64_note = cpu_common_write_elf64_note;
>      k->gdb_read_register = cpu_common_gdb_read_register;
>      k->gdb_write_register = cpu_common_gdb_write_register;
> -    k->virtio_is_big_endian = cpu_common_virtio_is_big_endian;
>      set_bit(DEVICE_CATEGORY_CPU, dc->categories);
>      dc->realize = cpu_common_realizefn;
>      dc->unrealize = cpu_common_unrealizefn;
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 1fd1917ca0f..fe6a4be99e4 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -1973,9 +1973,7 @@ static enum virtio_device_endian virtio_default_endian(void)
>  
>  static enum virtio_device_endian virtio_current_cpu_endian(void)
>  {
> -    CPUClass *cc = CPU_GET_CLASS(current_cpu);
> -
> -    if (cc->virtio_is_big_endian(current_cpu)) {
> +    if (cpu_virtio_is_big_endian(current_cpu)) {
>          return VIRTIO_DEVICE_ENDIAN_BIG;
>      } else {
>          return VIRTIO_DEVICE_ENDIAN_LITTLE;
> -- 
> 2.26.2