Re: [PATCH 6/7] hw/arm/virt: spe: Add SPE fdt binding for virt machine

[Andrew Jones]

On Fri, Aug 07, 2020 at 08:10:36AM +0000, Haibo Xu wrote:
> Add a virtual SPE device for virt machine while using PPI 
> 5 for SPE overflow interrupt number.

Any reason PPI 5 was selected?

> 
> Signed-off-by: Haibo Xu <haibo.xu@linaro.org>
> ---
>  hw/arm/virt-acpi-build.c    |  3 +++ 
>  hw/arm/virt.c               | 42 +++++++++++++++++++++++++++++++++++++
>  include/hw/acpi/acpi-defs.h |  1 + 
>  include/hw/arm/virt.h       |  1 + 
>  target/arm/cpu.c            |  2 ++
>  target/arm/cpu.h            |  2 ++
>  target/arm/kvm.c            |  6 ++++++
>  7 files changed, 57 insertions(+)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 91f0df7b13..5073ba22a5 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -666,6 +666,9 @@ build_madt(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>          if (arm_feature(&armcpu->env, ARM_FEATURE_PMU)) {
>              gicc->performance_interrupt = cpu_to_le32(PPI(VIRTUAL_PMU_IRQ));
>          }
> +        if (arm_feature(&armcpu->env, ARM_FEATURE_SPE)) {
> +            gicc->spe_interrupt = cpu_to_le32(PPI(VIRTUAL_SPE_IRQ));
> +        }
>          if (vms->virt) {
>              gicc->vgic_interrupt = cpu_to_le32(PPI(ARCH_GIC_MAINT_IRQ));
>          }
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index ecfee362a1..c40819705d 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -555,6 +555,42 @@ static void fdt_add_pmu_nodes(const VirtMachineState 
> *vms)
>      }
>  }
> 
> +static void fdt_add_spe_nodes(const VirtMachineState *vms)
> +{
> +    CPUState *cpu;
> +    ARMCPU *armcpu;
> +    uint32_t irqflags = GIC_FDT_IRQ_FLAGS_LEVEL_HI;
> +
> +    CPU_FOREACH(cpu) {
> +        armcpu = ARM_CPU(cpu);
> +        if (!arm_feature(&armcpu->env, ARM_FEATURE_SPE)) {
> +            return;
> +        }
> +        if (kvm_enabled()) {
> +            if (kvm_irqchip_in_kernel()) {
> +                kvm_arm_spe_set_irq(cpu, PPI(VIRTUAL_SPE_IRQ));
> +            }
> +            kvm_arm_spe_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, "/spe");
> +    if (arm_feature(&armcpu->env, ARM_FEATURE_V8)) {
> +        const char compat[] = "arm,statistical-profiling-extension-v1";
> +        qemu_fdt_setprop(vms->fdt, "/spe", "compatible",
> +                         compat, sizeof(compat));
> +        qemu_fdt_setprop_cells(vms->fdt, "/spe", "interrupts",
> +                               GIC_FDT_IRQ_TYPE_PPI, VIRTUAL_SPE_IRQ, 
> irqflags);
> +    }
> +}

Please look at [1]. I've refactored fdt_add_pmu_nodes(), so it no longer
makes a good pattern for this function.

[1] https://www.mail-archive.com/qemu-devel@nongnu.org/msg727588.html


> +
>  static inline DeviceState *create_acpi_ged(VirtMachineState *vms)
>  {
>      DeviceState *dev;
> @@ -727,6 +763,10 @@ static void create_gic(VirtMachineState *vms)
>                                      qdev_get_gpio_in(vms->gic, ppibase
>                                                       + VIRTUAL_PMU_IRQ));
> 
> +        qdev_connect_gpio_out_named(cpudev, "spe-interrupt", 0,
> +                                    qdev_get_gpio_in(vms->gic, ppibase
> +                                                     + VIRTUAL_SPE_IRQ));
> +
>          sysbus_connect_irq(gicbusdev, i, qdev_get_gpio_in(cpudev, 
> ARM_CPU_IRQ));
>          sysbus_connect_irq(gicbusdev, i + smp_cpus,
>                             qdev_get_gpio_in(cpudev, ARM_CPU_FIQ));
> @@ -1915,6 +1955,8 @@ static void machvirt_init(MachineState *machine)
> 
>      fdt_add_pmu_nodes(vms);
> 
> +    fdt_add_spe_nodes(vms);
> +

You didn't add any compat code, which means all virt machine types are now
getting an SPE FDT node, ACPI table change, and, most importantly, PPI 5
has gone from unallocated to allocated. We definitely need compat code.

>      create_uart(vms, VIRT_UART, sysmem, serial_hd(0));
> 
>      if (vms->secure) {
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index 38a42f409a..56a7f38ae4 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -302,6 +302,7 @@ struct AcpiMadtGenericCpuInterface {
>      uint32_t vgic_interrupt;
>      uint64_t gicr_base_address;
>      uint64_t arm_mpidr;
> +    uint16_t spe_interrupt; /* ACPI 6.3 */
>  } QEMU_PACKED;
> 
>  typedef struct AcpiMadtGenericCpuInterface AcpiMadtGenericCpuInterface;
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index dff67e1bef..56c83224d2 100644
> --- a/include/hw/arm/virt.h
> +++ b/include/hw/arm/virt.h
> @@ -49,6 +49,7 @@
>  #define ARCH_TIMER_NS_EL1_IRQ 14
>  #define ARCH_TIMER_NS_EL2_IRQ 10
> 
> +#define VIRTUAL_SPE_IRQ 5
>  #define VIRTUAL_PMU_IRQ 7
> 
>  #define PPI(irq) ((irq) + 16)
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 40768b4d19..67ab0089fd 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -1038,6 +1038,8 @@ static void arm_cpu_initfn(Object *obj)
>                               "gicv3-maintenance-interrupt", 1);
>      qdev_init_gpio_out_named(DEVICE(cpu), &cpu->pmu_interrupt,
>                               "pmu-interrupt", 1);
> +    qdev_init_gpio_out_named(DEVICE(cpu), &cpu->spe_interrupt,
> +                             "spe-interrupt", 1);
>  #endif
> 
>      /* DTB consumers generally don't in fact care what the 'compatible'
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index fe0ac14386..4bf8591df8 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -790,6 +790,8 @@ struct ARMCPU {
>      qemu_irq gicv3_maintenance_interrupt;
>      /* GPIO output for the PMU interrupt */
>      qemu_irq pmu_interrupt;
> +    /* GPIO output for the SPE interrupt */
> +    qemu_irq spe_interrupt;
> 
>      /* MemoryRegion to use for secure physical accesses */
>      MemoryRegion *secure_memory;
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 58f991e890..ecafdda364 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -820,6 +820,12 @@ MemTxAttrs kvm_arch_post_run(CPUState *cs, struct 
> kvm_run *run)
>              switched_level &= ~KVM_ARM_DEV_PMU;
>          }
> 
> +        if (switched_level & KVM_ARM_DEV_SPE) {
> +            qemu_set_irq(cpu->spe_interrupt,
> +                         !!(run->s.regs.device_irq_level & KVM_ARM_DEV_SPE));
> +            switched_level &= ~KVM_ARM_DEV_SPE;
> +        }
> +

Did you test with a userspace irqchip?

>          if (switched_level) {
>              qemu_log_mask(LOG_UNIMP, "%s: unhandled in-kernel device IRQ 
> %x\n",
>                            __func__, switched_level);
> -- 
> 2.17.1
> 
>

Thanks,
drew