[PATCH v7 19/19] KVM: ARM64: Add a new kvm ARM PMU device

Marc Zyngier
2015-12-15T15:33:01Z

On 15/12/15 08:49, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
>
> Add a new kvm device type KVM_DEV_TYPE_ARM_PMU_V3 for ARM PMU. Implement
> the kvm_device_ops for it.
>
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> ---
> Documentation/virtual/kvm/devices/arm-pmu.txt | 16 ++++
> arch/arm64/include/uapi/asm/kvm.h | 3 +
> include/linux/kvm_host.h | 1 +
> include/uapi/linux/kvm.h | 2 +
> virt/kvm/arm/pmu.c | 115 ++++++++++++++++++++++++++
> virt/kvm/kvm_main.c | 4 +
> 6 files changed, 141 insertions(+)
> create mode 100644 Documentation/virtual/kvm/devices/arm-pmu.txt
>
> diff --git a/Documentation/virtual/kvm/devices/arm-pmu.txt b/Documentation/virtual/kvm/devices/arm-pmu.txt
> new file mode 100644
> index 0000000..5121f1f
> --- /dev/null
> +++ b/Documentation/virtual/kvm/devices/arm-pmu.txt
> @@ -0,0 +1,16 @@
> +ARM Virtual Performance Monitor Unit (vPMU)
> +===========================================
> +
> +Device types supported:
> + KVM_DEV_TYPE_ARM_PMU_V3 ARM Performance Monitor Unit v3
> +
> +Instantiate one PMU instance for per VCPU through this API.
> +
> +Groups:
> + KVM_DEV_ARM_PMU_GRP_IRQ
> + Attributes:
> + A value describing the interrupt number of PMU overflow interrupt. This
> + interrupt should be a PPI.
> +
> + Errors:
> + -EINVAL: Value set is out of the expected range (from 16 to 31)
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 2d4ca4b..568afa2 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -204,6 +204,9 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_GRP_CTRL 4
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
>
> +/* Device Control API: ARM PMU */
> +#define KVM_DEV_ARM_PMU_GRP_IRQ 0
> +
> /* KVM_IRQ_LINE irq field index values */
> #define KVM_ARM_IRQ_TYPE_SHIFT 24
> #define KVM_ARM_IRQ_TYPE_MASK 0xff
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index c923350..608dea6 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1161,6 +1161,7 @@ extern struct kvm_device_ops kvm_mpic_ops;
> extern struct kvm_device_ops kvm_xics_ops;
> extern struct kvm_device_ops kvm_arm_vgic_v2_ops;
> extern struct kvm_device_ops kvm_arm_vgic_v3_ops;
> +extern struct kvm_device_ops kvm_arm_pmu_ops;
>
> #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 03f3618..4ba6fdd 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1032,6 +1032,8 @@ enum kvm_device_type {
> #define KVM_DEV_TYPE_FLIC KVM_DEV_TYPE_FLIC
> KVM_DEV_TYPE_ARM_VGIC_V3,
> #define KVM_DEV_TYPE_ARM_VGIC_V3 KVM_DEV_TYPE_ARM_VGIC_V3
> + KVM_DEV_TYPE_ARM_PMU_V3,
> +#define KVM_DEV_TYPE_ARM_PMU_V3 KVM_DEV_TYPE_ARM_PMU_V3
> KVM_DEV_TYPE_MAX,
> };
>
> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
> index d113ee4..1965d0d 100644
> --- a/virt/kvm/arm/pmu.c
> +++ b/virt/kvm/arm/pmu.c
> @@ -19,6 +19,7 @@
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> #include <linux/perf_event.h>
> +#include <linux/uaccess.h>
> #include <asm/kvm_emulate.h>
> #include <kvm/arm_pmu.h>
> #include <kvm/arm_vgic.h>
> @@ -357,3 +358,117 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
>
> pmc->perf_event = event;
> }
> +
> +static inline bool kvm_arm_pmu_initialized(struct kvm_vcpu *vcpu)
> +{
> + return vcpu->arch.pmu.irq_num != -1;
> +}
> +
> +static int kvm_arm_pmu_irq_access(struct kvm *kvm, int *irq, bool is_set)
> +{
> + int j;
> + struct kvm_vcpu *vcpu;
> +
> + kvm_for_each_vcpu(j, vcpu, kvm) {
> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
> +
> + if (!is_set) {
> + if (!kvm_arm_pmu_initialized(vcpu))
> + return -EBUSY;

Returning -EBUSY is a bit odd. Maybe -EINVAL? But this seems weird
anyway. Actually, why would you return an error in this case?

> +
> + *irq = pmu->irq_num;
> + break;
> + }
> +
> + if (kvm_arm_pmu_initialized(vcpu))
> + return -EBUSY;
> +
> + kvm_debug("Set kvm ARM PMU irq: %d\n", *irq);
> + pmu->irq_num = *irq;
> + }
> +
> + return 0;
> +}
> +
> +static int kvm_arm_pmu_create(struct kvm_device *dev, u32 type)
> +{
> + int i;
> + struct kvm_vcpu *vcpu;
> + struct kvm *kvm = dev->kvm;
> +
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
> +
> + memset(pmu, 0, sizeof(*pmu));
> + kvm_pmu_vcpu_reset(vcpu);
> + pmu->irq_num = -1;
> + }
> +
> + return 0;
> +}
> +
> +static void kvm_arm_pmu_destroy(struct kvm_device *dev)
> +{
> + kfree(dev);
> +}
> +
> +static int kvm_arm_pmu_set_attr(struct kvm_device *dev,
> + struct kvm_device_attr *attr)
> +{
> + switch (attr->group) {
> + case KVM_DEV_ARM_PMU_GRP_IRQ: {
> + int __user *uaddr = (int __user *)(long)attr->addr;
> + int reg;
> +
> + if (get_user(reg, uaddr))
> + return -EFAULT;
> +
> + if (reg < VGIC_NR_SGIS || reg >= VGIC_NR_PRIVATE_IRQS)
> + return -EINVAL;
> +
> + return kvm_arm_pmu_irq_access(dev->kvm, &reg, true);
> + }
> + }
> +
> + return -ENXIO;
> +}
> +
> +static int kvm_arm_pmu_get_attr(struct kvm_device *dev,
> + struct kvm_device_attr *attr)
> +{
> + int ret;
> +
> + switch (attr->group) {
> + case KVM_DEV_ARM_PMU_GRP_IRQ: {
> + int __user *uaddr = (int __user *)(long)attr->addr;
> + int reg = -1;
> +
> + ret = kvm_arm_pmu_irq_access(dev->kvm, &reg, false);
> + if (ret)
> + return ret;
> + return put_user(reg, uaddr);
> + }
> + }
> +
> + return -ENXIO;
> +}
> +
> +static int kvm_arm_pmu_has_attr(struct kvm_device *dev,
> + struct kvm_device_attr *attr)
> +{
> + switch (attr->group) {
> + case KVM_DEV_ARM_PMU_GRP_IRQ:
> + return 0;
> + }
> +
> + return -ENXIO;
> +}
> +
> +struct kvm_device_ops kvm_arm_pmu_ops = {
> + .name = "kvm-arm-pmu",
> + .create = kvm_arm_pmu_create,
> + .destroy = kvm_arm_pmu_destroy,
> + .set_attr = kvm_arm_pmu_set_attr,
> + .get_attr = kvm_arm_pmu_get_attr,
> + .has_attr = kvm_arm_pmu_has_attr,
> +};
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 484079e..81a42cc 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2647,6 +2647,10 @@ static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
> #ifdef CONFIG_KVM_XICS
> [KVM_DEV_TYPE_XICS] = &kvm_xics_ops,
> #endif
> +
> +#ifdef CONFIG_KVM_ARM_PMU
> + [KVM_DEV_TYPE_ARM_PMU_V3] = &kvm_arm_pmu_ops,
> +#endif
> };
>
> int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
>

Thanks,

M.
--
Jazz is not dead. It just smells funny...