Re: [Qemu-devel] [PATCH] ppc/spapr: Add H_PROD and H_CONFER

[Cédric Le Goater]

On 4/12/19 5:28 AM, Nicholas Piggin wrote:
> Cédric Le Goater's on April 11, 2019 4:34 pm:
>> From: Benjamin Herrenschmidt <address@hidden>
>>
>> H_PROD should be fully functional, H_CEDE is modified to
>> ignore a proded CPU. H_CONFER is a stub to avoid returning
>> an error.
> 
> Huh, I just implemented these a couple of days ago to test pseries
> suspend, also H_JOIN.

Cool. Can you send your version instead ?

Thanks,

C.

> 
> ---
>  hw/ppc/spapr_hcall.c | 79 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 8a736797b9..47ee933333 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1065,6 +1065,81 @@ static target_ulong h_cede(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>      return H_SUCCESS;
>  }
>  
> +static target_ulong h_join(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           target_ulong opcode, target_ulong *args)
> +{
> +    CPUPPCState *env = &cpu->env;
> +    CPUState *cs = CPU(cpu);
> +
> +    if (env->msr & (1ULL << MSR_EE))
> +        return H_BAD_MODE;
> +
> +    /*
> +     * This should check for single-threaded mode. In practice, Linux
> +     * does not try to H_JOIN all CPUs.
> +     */
> +
> +    cs->halted = 1;
> +    cs->exception_index = EXCP_HALTED;
> +    cs->exit_request = 1;
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_confer(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           target_ulong opcode, target_ulong *args)
> +{
> +    target_long target = args[0];
> +    CPUState *cs = CPU(cpu);
> +
> +    /*
> +     * This does not do a targeted yield, but check the parameter anyway.
> +     */
> +    if (target != -1 && !CPU(spapr_find_cpu(target)))
> +        return H_PARAMETER;
> +
> +    /*
> +     * H_CONFER with target == this is not exactly the same as H_JOIN
> +     * according to PAPR (e.g., MSR[EE] check and single threaded check
> +     * is not done in this case), but unlikely to matter.
> +     */
> +    if (cpu == spapr_find_cpu(target))
> +        return h_join(cpu, spapr, opcode, args);
> +
> +    /*
> +     * This does not implement the dispatch sequence check.
> +     */
> +    cs->exception_index = EXCP_YIELD;
> +    cpu_loop_exit(cs);
> +
> +    return H_SUCCESS;
> +}
> +
> +/*
> + * H_PROD and H_CONFER are specified to only modify GPR r3, which is not
> + * achievable running under KVM, although KVM already implements H_CONFER
> + * this way.
> + */
> +static target_ulong h_prod(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           target_ulong opcode, target_ulong *args)
> +{
> +    target_long target = args[0];
> +    CPUState *cs;
> +
> +    /*
> +     * Should set the prod flag in the VPA.
> +     */
> +
> +    cs = CPU(spapr_find_cpu(target));
> +    if (!cs)
> +        return H_PARAMETER;
> +
> +    cs->halted = 0;
> +    qemu_cpu_kick(cs);
> +
> +    return H_SUCCESS;
> +}
> +
>  static target_ulong h_rtas(PowerPCCPU *cpu, SpaprMachineState *spapr,
>                             target_ulong opcode, target_ulong *args)
>  {
> @@ -1860,6 +1935,10 @@ 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_CONFER, h_confer);
> +    spapr_register_hypercall(H_JOIN, h_join);
> +    spapr_register_hypercall(H_PROD, h_prod);
> +
>      spapr_register_hypercall(H_SIGNAL_SYS_RESET, h_signal_sys_reset);
>  
>      /* processor register resource access h-calls */
>