Re: [Qemu-devel] [QEMU-PPC] [PATCH 1/2] ppc/spapr: Add implementation of hcall H_PURR

[David Gibson]

On Mon, Jun 24, 2019 at 03:58:11PM +1000, Suraj Jitindar Singh wrote:
> The hcall H_PURR is used by a guest to read the PURR (processor
> utilisation of resources register). A guest expects that this register
> will count at a rate of timebase scaled by the number of guest vcpus
> present in the vcore. That is the per vcpu purr will count at a rate of
> timebase / # vcpus per vcore.
> 
> Implement a handler for the H_PURR hcall and return the purr value
> divided by smp_threads so that the sum of the purr deltas across the
> vcpus of a vcore equals the timebase delta
> 
> Signed-off-by: Suraj Jitindar Singh <address@hidden>

Does this need something new advertised in the hypertas DT entry?

> ---
>  hw/ppc/spapr_hcall.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index aae9fd2b3e..88b3343f04 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1819,6 +1819,27 @@ static target_ulong h_update_dt(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>      return H_SUCCESS;
>  }
>  
> +static target_ulong h_purr(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                           target_ulong opcode, target_ulong *args)
> +{
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong purr;
> +
> +    if (kvm_enabled()) {
> +        cpu_synchronize_state(CPU(cpu));
> +        /*
> +         * Divide by smp_threads so that the sum of the purr deltas across 
> the
> +         * vcpus of a vcore equal the timebase delta.
> +         */
> +        purr = env->spr[SPR_PURR] / smp_threads;
> +    } else {
> +        purr = cpu_ppc_load_purr(env);
> +    }
> +    args[0] = purr;
> +
> +    return H_SUCCESS;
> +}
> +
>  static spapr_hcall_fn papr_hypercall_table[(MAX_HCALL_OPCODE / 4) + 1];
>  static spapr_hcall_fn kvmppc_hypercall_table[KVMPPC_HCALL_MAX - 
> KVMPPC_HCALL_BASE + 1];
>  
> @@ -1915,6 +1936,9 @@ static void hypercall_register_types(void)
>      spapr_register_hypercall(H_LOGICAL_DCBF, h_logical_dcbf);
>      spapr_register_hypercall(KVMPPC_H_LOGICAL_MEMOP, h_logical_memop);
>  
> +    /* hcall-purr */
> +    spapr_register_hypercall(H_PURR, h_purr);
> +
>      /* qemu/KVM-PPC specific hcalls */
>      spapr_register_hypercall(KVMPPC_H_RTAS, h_rtas);
>  

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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