Re: [Qemu-devel] [Qemu-ppc] [PATCH 3/3] ppc/spapr: implement H_SIGNAL_SYS_RESET

[Greg Kurz <groug@kaod.org>]

On Thu, 20 Oct 2016 17:59:12 +1100
Nicholas Piggin <npiggin@gmail.com> wrote:

> The H_SIGNAL_SYS_RESET hcall allows a guest CPU to raise a system
> reset exception on other CPUs in the same guest.
> 

Actually on all CPUs or all-but-self CPUs or a specific CPU (including self).

> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  hw/ppc/spapr_hcall.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |  8 +++++++-
>  2 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index c5e7e8c..5ae84f0 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -880,6 +880,47 @@ static target_ulong h_set_mode(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>      return ret;
>  }
>  
> +static void do_sys_reset(CPUState *cs, void *arg)
> +{
> +    cpu_synchronize_state(cs);
> +    ppc_cpu_do_system_reset(cs);
> +}
> +

We already have the following function in hw/ppc/spapr.c, which serves the
same purpose:

static void ppc_cpu_do_nmi_on_cpu(CPUState *cs, void *arg)
{
    cpu_synchronize_state(cs);
    ppc_cpu_do_system_reset(cs);
}

What about using it ?

> +static target_ulong h_signal_sys_reset(PowerPCCPU *cpu,
> +                                       sPAPRMachineState *spapr,
> +                                       target_ulong opcode, target_ulong *args)
> +{
> +    target_long target = args[0];
> +    CPUState *cs;
> +
> +    if (target < H_SIGNAL_SYS_RESET_ALLBUTSELF) {
> +        return H_PARAMETER;
> +    }
> +
> +    CPU_FOREACH(cs) {
> +        PowerPCCPU *c = POWERPC_CPU(cs);
> +
> +        if (cpu->cpu_dt_id == target) {
> +            run_on_cpu(cs, do_sys_reset, NULL);
> +            return H_SUCCESS;
> +        }
> +
> +        if (target == H_SIGNAL_SYS_RESET_ALLBUTSELF) {
> +            if (c == cpu) {
> +                continue;
> +            }
> +        }
> +
> +        run_on_cpu(cs, do_sys_reset, NULL);
> +    }
> +
> +    if (target >= 0) {
> +        return H_PARAMETER;
> +    }
> +
> +    return H_SUCCESS;
> +}
> +
>  /*
>   * Return the offset to the requested option vector @vector in the
>   * option vector table @table.
> @@ -1113,6 +1154,7 @@ 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_SIGNAL_SYS_RESET, h_signal_sys_reset);
>  
>      /* processor register resource access h-calls */
>      spapr_register_hypercall(H_SET_SPRG0, h_set_sprg0);
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index aeaba3e..a28538b 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -339,7 +339,13 @@ struct sPAPRMachineState {
>  #define H_XIRR_X                0x2FC
>  #define H_RANDOM                0x300
>  #define H_SET_MODE              0x31C
> -#define MAX_HCALL_OPCODE        H_SET_MODE
> +#define H_SIGNAL_SYS_RESET      0x380
> +#define MAX_HCALL_OPCODE        H_SIGNAL_SYS_RESET
> +
> +/* Parameters to H_SIGNAL_SYS_RESET */
> +#define H_SIGNAL_SYS_RESET_ALL         -1
> +#define H_SIGNAL_SYS_RESET_ALLBUTSELF  -2
> +

I'd rather move these to hw/ppc/spapr_hcall.c just above h_signal_sys_reset(),
the same way it is done for h_bulk_remove().

>  
>  /* The hcalls above are standardized in PAPR and implemented by pHyp
>   * as well.