Re: [Qemu-devel] [PATCH v2 2/3] hw/arm/virt: Add PMU node for virt machine

[Andrew Jones <drjones@redhat.com>]

On Sat, Apr 23, 2016 at 06:04:14PM +0800, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
> 
> Add a virtual PMU device for virt machine while use PPI 7 for PMU
> overflow interrupt number.
> 
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> ---
>  hw/arm/virt.c         | 31 +++++++++++++++++++++++++++++++
>  include/hw/arm/virt.h |  4 ++++
>  include/sysemu/kvm.h  |  1 +
>  stubs/kvm.c           |  5 +++++
>  target-arm/kvm64.c    | 39 +++++++++++++++++++++++++++++++++++++++
>  5 files changed, 80 insertions(+)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 56d35c7..d77b314 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -428,6 +428,35 @@ static void fdt_add_gic_node(VirtBoardInfo *vbi, int type)
>      qemu_fdt_setprop_cell(vbi->fdt, "/intc", "phandle", vbi->gic_phandle);
>  }
>  
> +static void fdt_add_pmu_nodes(const VirtBoardInfo *vbi)
> +{
> +    CPUState *cpu;
> +    ARMCPU *armcpu;
> +    uint32_t irqflags = GIC_FDT_IRQ_FLAGS_LEVEL_HI;
> +
> +    CPU_FOREACH(cpu) {
> +        armcpu = ARM_CPU(cpu);
> +        if (!armcpu->has_pmu) {
> +            return;
> +        }
> +
> +        kvm_arm_pmu_create(cpu, PPI(VIRTUAL_PMU_IRQ));
> +    }
> +
> +    irqflags = deposit32(irqflags, GIC_FDT_IRQ_PPI_CPU_START,
> +                         GIC_FDT_IRQ_PPI_CPU_WIDTH, (1 << vbi->smp_cpus) - 1);

The shift will overflow when configuring a machine to have more than
32 cpus. You should confirm smp_cpus is <= GIC_FDT_IRQ_PPI_CPU_WIDTH
before generating a mask this way, otherwise you can just pass in 0xff.

> +
> +    armcpu = ARM_CPU(qemu_get_cpu(0));
> +    qemu_fdt_add_subnode(vbi->fdt, "/pmu");
> +    if (arm_feature(&armcpu->env, ARM_FEATURE_V8)) {
> +        const char compat[] = "arm,armv8-pmuv3";
> +        qemu_fdt_setprop(vbi->fdt, "/pmu", "compatible",
> +                         compat, sizeof(compat));
> +        qemu_fdt_setprop_cells(vbi->fdt, "/pmu", "interrupts",
> +                               GIC_FDT_IRQ_TYPE_PPI, VIRTUAL_PMU_IRQ, irqflags);
> +    }
> +}
> +
>  static void create_v2m(VirtBoardInfo *vbi, qemu_irq *pic)
>  {
>      int i;
> @@ -1246,6 +1275,8 @@ static void machvirt_init(MachineState *machine)
>  
>      create_gic(vbi, pic, gic_version, vms->secure);
>  
> +    fdt_add_pmu_nodes(vbi);
> +
>      create_uart(vbi, pic, VIRT_UART, sysmem);
>  
>      if (vms->secure) {
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index ecd8589..b50f095 100644
> --- a/include/hw/arm/virt.h
> +++ b/include/hw/arm/virt.h
> @@ -40,6 +40,10 @@
>  #define ARCH_TIMER_NS_EL1_IRQ 14
>  #define ARCH_TIMER_NS_EL2_IRQ 10
>  
> +#define VIRTUAL_PMU_IRQ 7
> +
> +#define PPI(irq) ((irq) + 16)
> +
>  enum {
>      VIRT_FLASH,
>      VIRT_MEM,
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 0e18f15..90c2c54 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -523,4 +523,5 @@ int kvm_set_one_reg(CPUState *cs, uint64_t id, void *source);
>   * Returns: 0 on success, or a negative errno on failure.
>   */
>  int kvm_get_one_reg(CPUState *cs, uint64_t id, void *target);
> +void kvm_arm_pmu_create(CPUState *cs, int irq);
>  #endif
> diff --git a/stubs/kvm.c b/stubs/kvm.c
> index ddd6204..58a348a 100644
> --- a/stubs/kvm.c
> +++ b/stubs/kvm.c
> @@ -6,3 +6,8 @@ int kvm_arch_irqchip_create(MachineState *ms, KVMState *s)
>  {
>      return 0;
>  }
> +
> +void kvm_arm_pmu_create(CPUState *cs, int irq)
> +{
> +    return;
> +}
> diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
> index b364789..faec4fa 100644
> --- a/target-arm/kvm64.c
> +++ b/target-arm/kvm64.c
> @@ -382,6 +382,45 @@ static CPUWatchpoint *find_hw_watchpoint(CPUState *cpu, target_ulong addr)
>      return NULL;
>  }
>  
> +static bool kvm_arm_pmu_support_ctrl(CPUState *cs, struct kvm_device_attr *attr)
> +{
> +    return kvm_vcpu_ioctl(cs, KVM_HAS_DEVICE_ATTR, attr) == 0;
> +}
> +
> +void kvm_arm_pmu_create(CPUState *cs, int irq)
> +{
> +    int err;
> +
> +    struct kvm_device_attr attr = {
> +        .group = KVM_ARM_VCPU_PMU_V3_CTRL,
> +        .addr = (intptr_t)&irq,
> +        .attr = KVM_ARM_VCPU_PMU_V3_IRQ,
> +        .flags = 0,
> +    };
> +
> +    if (!kvm_arm_pmu_support_ctrl(cs, &attr)) {
> +        return;
> +    }
> +
> +    err = kvm_vcpu_ioctl(cs, KVM_SET_DEVICE_ATTR, &attr);
> +    if (err < 0) {
> +        fprintf(stderr, "KVM_{SET/GET}_DEVICE_ATTR failed: %s\n",

You know it's a KVM_SET_DEVICE_ATTR here, so why report SET/GET?

> +                strerror(-err));
> +        abort();
> +    }
> +
> +    attr.group = KVM_ARM_VCPU_PMU_V3_CTRL;
> +    attr.attr = KVM_ARM_VCPU_PMU_V3_INIT;
> +    attr.addr = 0;
> +    attr.flags = 0;
> +
> +    err = kvm_vcpu_ioctl(cs, KVM_SET_DEVICE_ATTR, &attr);
> +    if (err < 0) {
> +        fprintf(stderr, "KVM_{SET/GET}_DEVICE_ATTR failed: %s\n",

Same SET comment as above.

> +                strerror(-err));
> +        abort();
> +    }
> +}
>  
>  static inline void set_feature(uint64_t *features, int feature)
>  {
> -- 
> 2.0.4
> 
>

Thanks,
drew