Re: [PATCH 2/3] hw/arm/virt: Move kvm pmu setup to virt_cpu_post_init

[Peter Maydell <peter.maydell@linaro.org>]

On Sat, 11 Jul 2020 at 11:10, Andrew Jones <drjones@redhat.com> wrote:
>
> Move the KVM PMU setup part of fdt_add_pmu_nodes() to
> virt_cpu_post_init(), which is a more appropriate location. Now
> fdt_add_pmu_nodes() is also named more appropriately, because it
> no longer does anything but fdt node creation.
>
> No functional change intended.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  hw/arm/virt.c | 33 +++++++++++++++------------------
>  1 file changed, 15 insertions(+), 18 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index cb2fa99b1ef5..63ef530933e5 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -521,30 +521,15 @@ static void fdt_add_gic_node(VirtMachineState *vms)
>
>  static void fdt_add_pmu_nodes(const VirtMachineState *vms)
>  {
> -    CPUState *cpu;
> -    ARMCPU *armcpu;
> +    ARMCPU *armcpu = ARM_CPU(first_cpu);
>      uint32_t irqflags = GIC_FDT_IRQ_FLAGS_LEVEL_HI;
>
> -    CPU_FOREACH(cpu) {
> -        armcpu = ARM_CPU(cpu);
> -        if (!arm_feature(&armcpu->env, ARM_FEATURE_PMU)) {
> -            return;
> -        }

So previously we would say "if the CPU doesn't actually have
a PMU, don't put the PMU nodes in the FDT", but in the new logic
it looks like we put the PMU nodes in the FDT unconditionally ?

> -        if (kvm_enabled()) {
> -            if (kvm_irqchip_in_kernel()) {
> -                kvm_arm_pmu_set_irq(cpu, PPI(VIRTUAL_PMU_IRQ));
> -            }
> -            kvm_arm_pmu_init(cpu);
> -        }
> -    }
> -
>      if (vms->gic_version == VIRT_GIC_VERSION_2) {
>          irqflags = deposit32(irqflags, GIC_FDT_IRQ_PPI_CPU_START,
>                               GIC_FDT_IRQ_PPI_CPU_WIDTH,
>                               (1 << vms->smp_cpus) - 1);
>      }
>
> -    armcpu = ARM_CPU(qemu_get_cpu(0));
>      qemu_fdt_add_subnode(vms->fdt, "/pmu");
>      if (arm_feature(&armcpu->env, ARM_FEATURE_V8)) {
>          const char compat[] = "arm,armv8-pmuv3";
> @@ -1678,11 +1663,23 @@ static void finalize_gic_version(VirtMachineState *vms)
>   */
>  static void virt_cpu_post_init(VirtMachineState *vms)
>  {
> -    bool aarch64;
> +    bool aarch64, pmu;
> +    CPUState *cpu;
>
>      aarch64 = object_property_get_bool(OBJECT(first_cpu), "aarch64", NULL);
> +    pmu = object_property_get_bool(OBJECT(first_cpu), "pmu", NULL);
>
> -    if (!kvm_enabled()) {
> +    if (kvm_enabled()) {
> +        CPU_FOREACH(cpu) {
> +            if (pmu) {
> +                assert(arm_feature(&ARM_CPU(cpu)->env, ARM_FEATURE_PMU));
> +                if (kvm_irqchip_in_kernel()) {
> +                    kvm_arm_pmu_set_irq(cpu, PPI(VIRTUAL_PMU_IRQ));
> +                }
> +                kvm_arm_pmu_init(cpu);
> +            }
> +        }
> +    } else {
>          if (aarch64 && vms->highmem) {
>              int requested_pa_size = 64 - clz64(vms->highest_gpa);
>              int pamax = arm_pamax(ARM_CPU(first_cpu));

thanks
-- PMM