Re: [PATCH v13 18/26] target/riscv: add 'rva22u64' CPU

[Alistair Francis]

On Mon, Dec 18, 2023 at 10:56 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> This CPU was suggested by Alistair [1] and others during the profile
> design discussions. It consists of the bare 'rv64i' CPU with rva22u64
> enabled by default, like an alias of '-cpu rv64i,rva22u64=true'.
>
> Users now have an even easier way of consuming this user-mode profile by
> doing '-cpu rva22u64'. Extensions can be enabled/disabled at will on top
> of it.
>
> We can boot Linux with this "user-mode" CPU by doing:
>
> -cpu rva22u64,sv39=true,s=true,zifencei=true
>
> [1] 
> https://lore.kernel.org/qemu-riscv/CAKmqyKP7xzZ9Sx=-Lbx2Ob0qCfB7Z+JO944FQ2TQ+49mqo0q_Q@mail.gmail.com/
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu-qom.h     |  1 +
>  target/riscv/cpu.c         | 17 +++++++++++++++++
>  target/riscv/tcg/tcg-cpu.c |  9 +++++++++
>  3 files changed, 27 insertions(+)
>
> diff --git a/target/riscv/cpu-qom.h b/target/riscv/cpu-qom.h
> index 4d1aa54311..12fe78fc52 100644
> --- a/target/riscv/cpu-qom.h
> +++ b/target/riscv/cpu-qom.h
> @@ -35,6 +35,7 @@
>  #define TYPE_RISCV_CPU_BASE64           RISCV_CPU_TYPE_NAME("rv64")
>  #define TYPE_RISCV_CPU_BASE128          RISCV_CPU_TYPE_NAME("x-rv128")
>  #define TYPE_RISCV_CPU_RV64I            RISCV_CPU_TYPE_NAME("rv64i")
> +#define TYPE_RISCV_CPU_RVA22U64         RISCV_CPU_TYPE_NAME("rva22u64")
>  #define TYPE_RISCV_CPU_IBEX             RISCV_CPU_TYPE_NAME("lowrisc-ibex")
>  #define TYPE_RISCV_CPU_SHAKTI_C         RISCV_CPU_TYPE_NAME("shakti-c")
>  #define TYPE_RISCV_CPU_SIFIVE_E31       RISCV_CPU_TYPE_NAME("sifive-e31")
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index b9057c8da2..a38d78b2d6 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1576,6 +1576,15 @@ static Property riscv_cpu_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> +#if defined(TARGET_RISCV64)
> +static void rva22u64_profile_cpu_init(Object *obj)
> +{
> +    rv64i_bare_cpu_init(obj);
> +
> +    RVA22U64.enabled = true;
> +}
> +#endif
> +
>  static const gchar *riscv_gdb_arch_name(CPUState *cs)
>  {
>      RISCVCPU *cpu = RISCV_CPU(cs);
> @@ -1866,6 +1875,13 @@ void riscv_cpu_list(void)
>          .instance_init = initfn            \
>      }
>
> +#define DEFINE_PROFILE_CPU(type_name, initfn) \
> +    {                                         \
> +        .name = type_name,                    \
> +        .parent = TYPE_RISCV_BARE_CPU,        \
> +        .instance_init = initfn               \
> +    }
> +
>  static const TypeInfo riscv_cpu_type_infos[] = {
>      {
>          .name = TYPE_RISCV_CPU,
> @@ -1910,6 +1926,7 @@ static const TypeInfo riscv_cpu_type_infos[] = {
>      DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_VEYRON_V1,   rv64_veyron_v1_cpu_init),
>      DEFINE_DYNAMIC_CPU(TYPE_RISCV_CPU_BASE128,  rv128_base_cpu_init),
>      DEFINE_BARE_CPU(TYPE_RISCV_CPU_RV64I, rv64i_bare_cpu_init),
> +    DEFINE_PROFILE_CPU(TYPE_RISCV_CPU_RVA22U64, rva22u64_profile_cpu_init),
>  #endif
>  };
>
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index 005d8be26b..04aedf3840 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -1095,6 +1095,15 @@ static void riscv_cpu_add_profiles(Object *cpu_obj)
>          object_property_add(cpu_obj, profile->name, "bool",
>                              cpu_get_profile, cpu_set_profile,
>                              NULL, (void *)profile);
> +
> +        /*
> +         * CPUs might enable a profile right from the start.
> +         * Enable its mandatory extensions right away in this
> +         * case.
> +         */
> +        if (profile->enabled) {
> +            object_property_set_bool(cpu_obj, profile->name, true, NULL);
> +        }
>      }
>  }
>
> --
> 2.43.0
>
>