Re: [PATCH v2 03/10] target/riscv: add rva22u64 profile definition

[Alistair Francis <alistair23@gmail.com>]

On Fri, Oct 6, 2023 at 11:23 PM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> The rva22U64 profile, described in:
>
> https://github.com/riscv/riscv-profiles/blob/main/profiles.adoc#rva22-profiles
>
> Contains a set of CPU extensions aimed for 64-bit userspace
> applications. Enabling this set to be enabled via a single user flag
> makes it convenient to enable a predictable set of features for the CPU,
> giving users more predicability when running/testing their workloads.
>
> QEMU implements all possible extensions of this profile. The exception
> is Zicbop (Cache-Block Prefetch Operations) that is not available since
> QEMU RISC-V does not implement a cache model. For this same reason all
> the so called 'synthetic extensions' described in the profile that are
> cache related are ignored (Za64rs, Zic64b, Ziccif, Ziccrse, Ziccamoa,
> Zicclsm).
>
> An abstraction called RISCVCPUProfile is created to store the profile.
> 'ext_offsets' contains mandatory extensions that QEMU supports. Same
> thing with the 'misa_ext' mask. Optional extensions must be enabled
> manually in the command line if desired.
>
> The design here is to use the common target/riscv/cpu.c file to store
> the profile declaration and export it to the accelerator files. Each
> accelerator is then responsible to expose it (or not) to users and how
> to enable the extensions.
>
> Next patches will implement the profile for TCG and KVM.
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

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

Alistair

> ---
>  target/riscv/cpu.c | 20 ++++++++++++++++++++
>  target/riscv/cpu.h | 12 ++++++++++++
>  2 files changed, 32 insertions(+)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index b3befccf89..a439ff57a4 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1376,6 +1376,26 @@ Property riscv_cpu_options[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> +/* Optional extensions left out: RVV, zfh, zkn, zks */
> +static RISCVCPUProfile RVA22U64 = {
> +    .name = "rva22u64",
> +    .misa_ext = RVM | RVA | RVF | RVD | RVC,
> +    .ext_offsets = {
> +        CPU_CFG_OFFSET(ext_icsr), CPU_CFG_OFFSET(ext_zihintpause),
> +        CPU_CFG_OFFSET(ext_zba), CPU_CFG_OFFSET(ext_zbb),
> +        CPU_CFG_OFFSET(ext_zbs), CPU_CFG_OFFSET(ext_zfhmin),
> +        CPU_CFG_OFFSET(ext_zkt), CPU_CFG_OFFSET(ext_icntr),
> +        CPU_CFG_OFFSET(ext_ihpm), CPU_CFG_OFFSET(ext_icbom),
> +        CPU_CFG_OFFSET(ext_icboz),
> +
> +        RISCV_PROFILE_EXT_LIST_END
> +    }
> +};
> +
> +RISCVCPUProfile *riscv_profiles[] = {
> +    &RVA22U64, NULL,
> +};
> +
>  static Property riscv_cpu_properties[] = {
>      DEFINE_PROP_BOOL("debug", RISCVCPU, cfg.debug, true),
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 3f11e69223..216bbbe7cd 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -66,6 +66,18 @@ const char *riscv_get_misa_ext_description(uint32_t bit);
>
>  #define CPU_CFG_OFFSET(_prop) offsetof(struct RISCVCPUConfig, _prop)
>
> +typedef struct riscv_cpu_profile {
> +    const char *name;
> +    uint32_t misa_ext;
> +    bool enabled;
> +    bool user_set;
> +    const int32_t ext_offsets[];
> +} RISCVCPUProfile;
> +
> +#define RISCV_PROFILE_EXT_LIST_END -1
> +
> +extern RISCVCPUProfile *riscv_profiles[];
> +
>  /* Privileged specification version */
>  enum {
>      PRIV_VERSION_1_10_0 = 0,
> --
> 2.41.0
>
>