Re: [PATCH] target/riscv: Wake on VS-level external interrupts

[Alistair Francis]

On Wed, Jun 1, 2022 at 7:07 AM Andrew Bresticker <abrestic@rivosinc.com> wrote:
>
> Whether or not VSEIP is pending isn't reflected in env->mip and must
> instead be determined from hstatus.vgein and hgeip. As a result a
> CPU in WFI won't wake on a VSEIP, which violates the WFI behavior as
> specified in the privileged ISA. Just use riscv_cpu_all_pending()
> instead, which already accounts for VSEIP.
>
> Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
>  target/riscv/cpu.c        | 2 +-
>  target/riscv/cpu.h        | 1 +
>  target/riscv/cpu_helper.c | 2 +-
>  3 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index a91253d4bd..c6cc08c355 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -391,7 +391,7 @@ static bool riscv_cpu_has_work(CPUState *cs)
>       * Definition of the WFI instruction requires it to ignore the privilege
>       * mode and delegation registers, but respect individual enables
>       */
> -    return (env->mip & env->mie) != 0;
> +    return riscv_cpu_all_pending(env) != 0;
>  #else
>      return true;
>  #endif
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index f08c3e8813..758ab6c90b 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -488,6 +488,7 @@ int riscv_cpu_gdb_read_register(CPUState *cpu, GByteArray 
> *buf, int reg);
>  int riscv_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
>  int riscv_cpu_hviprio_index2irq(int index, int *out_irq, int *out_rdzero);
>  uint8_t riscv_cpu_default_priority(int irq);
> +uint64_t riscv_cpu_all_pending(CPURISCVState *env);
>  int riscv_cpu_mirq_pending(CPURISCVState *env);
>  int riscv_cpu_sirq_pending(CPURISCVState *env);
>  int riscv_cpu_vsirq_pending(CPURISCVState *env);
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index d99fac9d2d..16c6045459 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -340,7 +340,7 @@ static int riscv_cpu_pending_to_irq(CPURISCVState *env,
>      return best_irq;
>  }
>
> -static uint64_t riscv_cpu_all_pending(CPURISCVState *env)
> +uint64_t riscv_cpu_all_pending(CPURISCVState *env)
>  {
>      uint32_t gein = get_field(env->hstatus, HSTATUS_VGEIN);
>      uint64_t vsgein = (env->hgeip & (1ULL << gein)) ? MIP_VSEIP : 0;
> --
> 2.25.1
>
>