Re: [Qemu-devel] [PATCH v5 2/4] spapr: Implement H_PROD

[Cédric Le Goater]

On 17/07/2019 07:39, Nicholas Piggin wrote:
> H_PROD is added, and H_CEDE is modified to test the prod bit
> according to PAPR.
> 
> Signed-off-by: Nicholas Piggin <address@hidden>
> ---
>  hw/ppc/spapr_hcall.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index e615881ac4..8b208ab259 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1050,14 +1050,41 @@ static target_ulong h_cede(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>  {
>      CPUPPCState *env = &cpu->env;
>      CPUState *cs = CPU(cpu);
> +    SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
>  
>      env->msr |= (1ULL << MSR_EE);
>      hreg_compute_hflags(env);
> +
> +    if (spapr_cpu->prod) {
> +        spapr_cpu->prod = false;
> +        return H_SUCCESS;
> +    }
> +
>      if (!cpu_has_work(cs)) {
>          cs->halted = 1;
>          cs->exception_index = EXCP_HLT;

Shouldn't that be EXCP_HALTED instead ? 

commit 1dd088946cf4 seems to say that h_cede is equivalent to the hlt 
instruction on x86 but in 7 years things have changed.

C. 

>          cs->exit_request = 1;
>      }
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_prod(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           target_ulong opcode, target_ulong *args)
> +{
> +    target_long target = args[0];
> +    CPUState *cs;
> +    SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
> +
> +    cs = CPU(spapr_find_cpu(target));
> +    if (!cs) {
> +        return H_PARAMETER;
> +    }
> +
> +    spapr_cpu->prod = true;
> +    cs->halted = 0;
> +    qemu_cpu_kick(cs);
> +
>      return H_SUCCESS;
>  }
>  
> @@ -1882,6 +1909,8 @@ static void hypercall_register_types(void)
>      /* hcall-splpar */
>      spapr_register_hypercall(H_REGISTER_VPA, h_register_vpa);
>      spapr_register_hypercall(H_CEDE, h_cede);
> +    spapr_register_hypercall(H_PROD, h_prod);
> +
>      spapr_register_hypercall(H_SIGNAL_SYS_RESET, h_signal_sys_reset);
>  
>      /* processor register resource access h-calls */
>