Re: [Qemu-devel] [PATCH v6 2/4] spapr: Implement H_PROD

[Greg Kurz <groug@kaod.org>]

On Thu, 18 Jul 2019 13:42:12 +1000
Nicholas Piggin <npiggin@gmail.com> wrote:

> H_PROD is added, and H_CEDE is modified to test the prod bit
> according to PAPR.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

> Changes since v5:
> - Add the prod bit here
> - Fix target CPU
> 
>  hw/ppc/spapr.c                  |  1 +
>  hw/ppc/spapr_hcall.c            | 32 ++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr_cpu_core.h |  1 +
>  3 files changed, 34 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 3e5678d467..68341c128d 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4309,6 +4309,7 @@ static void spapr_cpu_exec_enter(PPCVirtualHypervisor *vhyp, PowerPCCPU *cpu)
>  
>      /* These are only called by TCG, KVM maintains dispatch state */
>  
> +    spapr_cpu->prod = false;
>      if (spapr_cpu->vpa_addr) {
>          CPUState *cs = CPU(cpu);
>          uint32_t dispatch;
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index e615881ac4..098b3dda22 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1050,14 +1050,44 @@ 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;
>          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];
> +    PowerPCCPU *tcpu;
> +    CPUState *cs;
> +    SpaprCpuState *spapr_cpu;
> +
> +    tcpu = spapr_find_cpu(target);
> +    cs = CPU(tcpu);
> +    if (!cs) {
> +        return H_PARAMETER;
> +    }
> +
> +    spapr_cpu = spapr_cpu_state(tcpu);
> +    spapr_cpu->prod = true;
> +    cs->halted = 0;
> +    qemu_cpu_kick(cs);
> +
>      return H_SUCCESS;
>  }
>  
> @@ -1882,6 +1912,8 @@ 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 */
> diff --git a/include/hw/ppc/spapr_cpu_core.h b/include/hw/ppc/spapr_cpu_core.h
> index f9645a7290..a40cd08ea0 100644
> --- a/include/hw/ppc/spapr_cpu_core.h
> +++ b/include/hw/ppc/spapr_cpu_core.h
> @@ -46,6 +46,7 @@ typedef struct SpaprCpuState {
>      uint64_t vpa_addr;
>      uint64_t slb_shadow_addr, slb_shadow_size;
>      uint64_t dtl_addr, dtl_size;
> +    bool prod; /* not migrated, only used to improve dispatch latencies */
>      struct ICPState *icp;
>      struct XiveTCTX *tctx;
>  } SpaprCpuState;