[PATCH 02/18] KVM: ARM64: Add initial support for PMU
Shannon Zhao
shannon.zhao at linaro.org
Fri Jul 17 01:13:35 PDT 2015
On 2015/7/17 2:25, Christoffer Dall wrote:
> On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao at linaro.org wrote:
>> From: Shannon Zhao <shannon.zhao at linaro.org>
>>
>> Here we plan to support virtual PMU for guest by full software
>> emulation, so define some basic structs and functions preparing for
>> futher steps. Define struct kvm_pmc for performance monitor counter and
>> struct kvm_pmu for performance monitor unit for each vcpu. According to
>> ARMv8 spec, the PMU contains at most 32(ARMV8_MAX_COUNTERS) counters.
>> Initialize PMU for each vcpu when kvm initialize vcpus, while reset PMU
>> when kvm reset vcpus.
>> Since this only supports ARM64 (or PMUv3), add a separate config symbol
>> for it.
>>
>> Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
>> ---
>> arch/arm/kvm/arm.c | 4 +++
>> arch/arm64/include/asm/kvm_host.h | 2 ++
>> arch/arm64/include/asm/pmu.h | 2 ++
>> arch/arm64/kvm/Kconfig | 7 +++++
>> arch/arm64/kvm/Makefile | 1 +
>> arch/arm64/kvm/reset.c | 3 +++
>> include/kvm/arm_pmu.h | 54 ++++++++++++++++++++++++++++++++++++++
>> virt/kvm/arm/pmu.c | 55 +++++++++++++++++++++++++++++++++++++++
>> 8 files changed, 128 insertions(+)
>> create mode 100644 include/kvm/arm_pmu.h
>> create mode 100644 virt/kvm/arm/pmu.c
>>
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index bc738d2..4e82625 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -28,6 +28,7 @@
>> #include <linux/sched.h>
>> #include <linux/kvm.h>
>> #include <trace/events/kvm.h>
>> +#include <kvm/arm_pmu.h>
>>
>> #define CREATE_TRACE_POINTS
>> #include "trace.h"
>> @@ -278,6 +279,9 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
>> /* Set up the timer */
>> kvm_timer_vcpu_init(vcpu);
>>
>> + /* Set up the PMU */
>> + kvm_pmu_init(vcpu);
>> +
>> return 0;
>> }
>>
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>> index 2709db2..3c88873 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -42,6 +42,7 @@
>>
>> #include <kvm/arm_vgic.h>
>> #include <kvm/arm_arch_timer.h>
>> +#include <kvm/arm_pmu.h>
>>
>> #define KVM_VCPU_MAX_FEATURES 3
>>
>> @@ -116,6 +117,7 @@ struct kvm_vcpu_arch {
>> /* VGIC state */
>> struct vgic_cpu vgic_cpu;
>> struct arch_timer_cpu timer_cpu;
>> + struct kvm_pmu pmu;
>>
>> /*
>> * Anything that is not used directly from assembly code goes
>> diff --git a/arch/arm64/include/asm/pmu.h b/arch/arm64/include/asm/pmu.h
>> index b9f394a..95681e6 100644
>> --- a/arch/arm64/include/asm/pmu.h
>> +++ b/arch/arm64/include/asm/pmu.h
>> @@ -19,6 +19,8 @@
>> #ifndef __ASM_PMU_H
>> #define __ASM_PMU_H
>>
>> +#include <linux/perf_event.h>
>> +
>> #define ARMV8_MAX_COUNTERS 32
>> #define ARMV8_COUNTER_MASK (ARMV8_MAX_COUNTERS - 1)
>>
>> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
>> index bfffe8f..eae3a1b 100644
>> --- a/arch/arm64/kvm/Kconfig
>> +++ b/arch/arm64/kvm/Kconfig
>> @@ -31,6 +31,7 @@ config KVM
>> select KVM_VFIO
>> select HAVE_KVM_EVENTFD
>> select HAVE_KVM_IRQFD
>> + select KVM_ARM_PMU
>> ---help---
>> Support hosting virtualized guest machines.
>>
>> @@ -52,4 +53,10 @@ config KVM_ARM_MAX_VCPUS
>> large, so only choose a reasonable number that you expect to
>> actually use.
>>
>> +config KVM_ARM_PMU
>> + bool
>> + depends on KVM_ARM_HOST
>> + ---help---
>> + Adds support for the Performance Monitoring in virtual machines.
>
> Adds support for a virtual Performance Monitoring Unit (PMU) in virtual
> machines.
>
>> +
>> endif # VIRTUALIZATION
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index f90f4aa..78db4ee 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -27,3 +27,4 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3-emul.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += vgic-v3-switch.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o
>> +kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o
>> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
>> index 0b43265..ee2c2e9 100644
>> --- a/arch/arm64/kvm/reset.c
>> +++ b/arch/arm64/kvm/reset.c
>> @@ -107,5 +107,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>> /* Reset timer */
>> kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq);
>>
>> + /* Reset PMU */
>> + kvm_pmu_vcpu_reset(vcpu);
>> +
>> return 0;
>> }
>> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
>> new file mode 100644
>> index 0000000..27d14ca
>> --- /dev/null
>> +++ b/include/kvm/arm_pmu.h
>> @@ -0,0 +1,54 @@
>> +/*
>> + * Copyright (C) 2015 Linaro Ltd.
>> + * Author: Shannon Zhao <shannon.zhao at linaro.org>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef __ASM_ARM_KVM_PMU_H
>> +#define __ASM_ARM_KVM_PMU_H
>> +
>> +#include <asm/pmu.h>
>> +#include <linux/irq_work.h>
>> +
>> +struct kvm_pmc {
>> + u8 idx;
>
> which index is this? Does it map to something architecturally or is it
> just the array index number?
>
It's the index of the PMU counter.
>> + u64 counter;
>> + u64 eventsel;
>
> does this map to PMEVTYPER<n>_EL0.evtCount?
>
No, it just stores the event type.
>> + bool interrupt;
>
> is this that an interrupt which is pending or which is enabled?
>
>> + bool enable;
>> + struct perf_event *perf_event;
>> + struct kvm_vcpu *vcpu;
>> +};
>> +
>> +struct kvm_pmu {
>> +#ifdef CONFIG_KVM_ARM_PMU
>> + /* PMU IRQ Number per VCPU */
>> + int irq_num;
>> + int overflow_status;
>> + /* IRQ pending flag */
>> + bool irq_pending;
>> + struct irq_work irq_work;
>> + struct kvm_pmc pmc[ARMV8_MAX_COUNTERS];
>> +#endif
>> +};
>> +
>> +#ifdef CONFIG_KVM_ARM_PMU
>> +void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu);
>> +void kvm_pmu_init(struct kvm_vcpu *vcpu);
>> +#else
>> +static inline void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) {}
>> +static inline void kvm_pmu_init(struct kvm_vcpu *vcpu) {}
>> +#endif
>> +
>> +#endif
>> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
>> new file mode 100644
>> index 0000000..dc252d0
>> --- /dev/null
>> +++ b/virt/kvm/arm/pmu.c
>> @@ -0,0 +1,55 @@
>> +/*
>> + * Copyright (C) 2015 Linaro Ltd.
>> + * Author: Shannon Zhao <shannon.zhao at linaro.org>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/cpu.h>
>> +#include <linux/kvm.h>
>> +#include <linux/kvm_host.h>
>> +#include <kvm/arm_pmu.h>
>> +
>> +/**
>> + * kvm_pmu_vcpu_reset - reset pmu state for cpu
>> + * @vcpu: The vcpu pointer
>> + *
>> + */
>> +void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
>> +{
>> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
>> +
>> + pmu->irq_pending = false;
>> +}
>> +
>> +/**
>> + * kvm_pmu_init - Initialize global PMU state for per vcpu
>
> how is this both global and per VCPU?
>
>> + * @vcpu: The vcpu pointer
>> + *
>> + * Initialize PMC and Set all the PMU IRQ numbers to invalid
>
> s/Set/set/
>
>> + * value so that user space has to explicitly provide PMU
>> + * IRQ numbers using set device address ioctl.
>> + */
>> +void kvm_pmu_init(struct kvm_vcpu *vcpu)
>> +{
>> + int i;
>> + struct kvm_pmu *pmu = &vcpu->arch.pmu;
>> +
>> + memset(pmu, 0, sizeof(*pmu));
>> + for (i = 0; i < ARMV8_MAX_COUNTERS; i++) {
>> + pmu->pmc[i].idx = i;
>> + pmu->pmc[i].vcpu = vcpu;
>> + }
>> +
>> + pmu->irq_num = -1;
>> +}
>> --
>> 2.1.0
>>
--
Shannon
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