On Thu, 31 Aug 2017 16:38:46 +1000 Sam Bobroff <sam.bobr...@au1.ibm.com> wrote:
> Move the calculation of a CPU's VCPU ID out of the generic PPC code
> (ppc_cpu_realizefn()) and into sPAPR specific code
> (spapr_cpu_core_realize()) where it belongs.
>
> Unfortunately, due to the way things are ordered, we still need to
> default the VCPU ID in ppc_cpu_realizfn() but at least doing that
> doesn't require any interaction with sPAPR.
>
> Signed-off-by: Sam Bobroff <sam.bobr...@au1.ibm.com>
> ---
> This is follow up work arising from my work to clean up the way CPU VCPU IDs
> are
> handled on PowerPC. It had looked like it would be difficult to move the
> actual
> VCPU ID calculation out of generic code but it turned out to be OK.
>
> It's based on dgibson/ppc-for-2.11.
>
> Cheers,
> Sam.
>
> hw/ppc/spapr_cpu_core.c | 11 +++++++++++
> target/ppc/translate_init.c | 18 +++---------------
> 2 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 5e319d9bbb..84dcc6e264 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -211,6 +211,7 @@ error:
>
> static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
> {
> + sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
> sPAPRCPUCoreClass *scc = SPAPR_CPU_CORE_GET_CLASS(OBJECT(dev));
> CPUCore *cc = CPU_CORE(OBJECT(dev));
> @@ -237,6 +238,16 @@ static void spapr_cpu_core_realize(DeviceState *dev,
> Error **errp)
> cs = CPU(obj);
> cpu = POWERPC_CPU(cs);
> cs->cpu_index = cc->core_id + i;
> + cpu->vcpu_id = (cc->core_id * spapr->vsmt / smp_threads) + i;
According to what we currently have in the generic code, this should be:
((cc->core_id + i) / smp_threads) * spapr->vsmt + ((cc->core_id + i) %
smp_threads)
but since cc->core_id is a multiple of smp_threads and i < cc->nr_threads <=
smp_threads,
then we can indeed simplify the computation as you did. :)
\o/
Reviewed-by: Greg Kurz <gr...@kaod.org>
> + if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->vcpu_id)) {
> + error_setg(&local_err, "Can't create CPU with id %d in KVM",
> + cpu->vcpu_id);
> + error_append_hint(&local_err, "Adjust the number of cpus to %d "
> + "or try to raise the number of threads per
> core\n",
> + cpu->vcpu_id * smp_threads / spapr->vsmt);
> + goto err;
> + }
> +
>
> /* Set NUMA node for the threads belonged to core */
> cpu->node_id = sc->node_id;
> diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
> index 7f6a349e43..1f7286c893 100644
> --- a/target/ppc/translate_init.c
> +++ b/target/ppc/translate_init.c
> @@ -9903,28 +9903,15 @@ static void ppc_cpu_realizefn(DeviceState *dev, Error
> **errp)
> PowerPCCPU *cpu = POWERPC_CPU(dev);
> PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> Error *local_err = NULL;
> -#if !defined(CONFIG_USER_ONLY)
> - int max_smt = kvmppc_smt_threads();
> -#endif
>
> cpu_exec_realizefn(cs, &local_err);
> if (local_err != NULL) {
> error_propagate(errp, local_err);
> return;
> }
> -
> -#if !defined(CONFIG_USER_ONLY)
> - cpu->vcpu_id = (cs->cpu_index / smp_threads) * max_smt
> - + (cs->cpu_index % smp_threads);
> -
> - if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->vcpu_id)) {
> - error_setg(errp, "Can't create CPU with id %d in KVM", cpu->vcpu_id);
> - error_append_hint(errp, "Adjust the number of cpus to %d "
> - "or try to raise the number of threads per core\n",
> - cpu->vcpu_id * smp_threads / max_smt);
> - goto unrealize;
> + if (cpu->vcpu_id == UNASSIGNED_CPU_INDEX) {
> + cpu->vcpu_id = cs->cpu_index;
> }
> -#endif
>
> if (tcg_enabled()) {
> if (ppc_fixup_cpu(cpu) != 0) {
> @@ -10625,6 +10612,7 @@ static void ppc_cpu_initfn(Object *obj)
> CPUPPCState *env = &cpu->env;
>
> cs->env_ptr = env;
> + cpu->vcpu_id = UNASSIGNED_CPU_INDEX;
>
> env->msr_mask = pcc->msr_mask;
> env->mmu_model = pcc->mmu_model;
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