[02/18] KVM: ARM64: Add initial support for PMU

Message ID 1436149068-3784-3-git-send-email-shannon.zhao@linaro.org
State New
Headers show

Commit Message

Shannon Zhao July 6, 2015, 2:17 a.m.
From: Shannon Zhao <shannon.zhao@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@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

Comments

Christoffer Dall July 16, 2015, 6:25 p.m. | #1
On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao@linaro.org wrote:
> From: Shannon Zhao <shannon.zhao@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@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@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?

> +	u64 counter;
> +	u64 eventsel;

does this map to PMEVTYPER<n>_EL0.evtCount?

> +	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@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 Zhao July 17, 2015, 8:13 a.m. | #2
On 2015/7/17 2:25, Christoffer Dall wrote:
> On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao@linaro.org wrote:
>> From: Shannon Zhao <shannon.zhao@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@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@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@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
>>
Christoffer Dall July 17, 2015, 9:58 a.m. | #3
On Fri, Jul 17, 2015 at 04:13:35PM +0800, Shannon Zhao wrote:
> 
> 
> On 2015/7/17 2:25, Christoffer Dall wrote:
> > On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao@linaro.org wrote:
> >> From: Shannon Zhao <shannon.zhao@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@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@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.
> 

sorry, I don't feel this answers my question? ;)

> >> +	u64 counter;
> >> +	u64 eventsel;
> > 
> > does this map to PMEVTYPER<n>_EL0.evtCount?
> > 
> No, it just stores the event type.
> 

can you specify more clearly what this maps to/how I derive its meaning?

Is this a perf (Linux) event type number, or an architecturally defined
thing?


Thanks,
-Christoffer
Shannon Zhao July 17, 2015, 11:34 a.m. | #4
On 2015/7/17 17:58, Christoffer Dall wrote:
> On Fri, Jul 17, 2015 at 04:13:35PM +0800, Shannon Zhao wrote:
>>
>>
>> On 2015/7/17 2:25, Christoffer Dall wrote:
>>> On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao@linaro.org wrote:
>>>> From: Shannon Zhao <shannon.zhao@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@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@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.
>>
>
> sorry, I don't feel this answers my question? ;)
>

This index is only used for kvm_pmu_perf_overflow to locate the index of 
this PMU counter and kvm_pmu_perf_overflow will set the corresponding 
bit of overflow_status to show whether this counter overflows.

See patch 17/18:

+static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
+				  struct perf_sample_data *data,
+				  struct pt_regs *regs)
+{
+	struct kvm_pmc *pmc = perf_event->overflow_handler_context;
+	struct kvm_vcpu *vcpu = pmc->vcpu;
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+
+	if (pmc->interrupt == true) {
+		__set_bit(pmc->idx, (unsigned long *)&pmu->overflow_status);

>>>> +	u64 counter;
>>>> +	u64 eventsel;
>>>
>>> does this map to PMEVTYPER<n>_EL0.evtCount?
>>>
>> No, it just stores the event type.
>>
>
> can you specify more clearly what this maps to/how I derive its meaning?
>
> Is this a perf (Linux) event type number, or an architecturally defined
> thing?
>

Yes, it stores a perf event type number. This is used for 
kvm_pmu_set_counter_event_type to check whether event type of this time 
is same with the previous one. If they are same, it will return and 
doesn't create a new perf event for it and just reuses the previous one.

See PATCH 07/18:

+void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, unsigned 
long data,
+				    unsigned long select_idx)
+{
+	struct kvm_pmu *pmu = &vcpu->arch.pmu;
+	struct kvm_pmc *pmc = &pmu->pmc[select_idx];
+	struct perf_event *event;
+	struct perf_event_attr attr;
+	unsigned config, type = PERF_TYPE_RAW;
+
+	if ((data & ARMV8_EVTYPE_EVENT) == pmc->eventsel)
+		return;

>
> Thanks,
> -Christoffer
>
Christoffer Dall July 17, 2015, 12:48 p.m. | #5
On Fri, Jul 17, 2015 at 07:34:58PM +0800, Shannon Zhao wrote:
> 
> 
> On 2015/7/17 17:58, Christoffer Dall wrote:
> >On Fri, Jul 17, 2015 at 04:13:35PM +0800, Shannon Zhao wrote:
> >>
> >>
> >>On 2015/7/17 2:25, Christoffer Dall wrote:
> >>>On Mon, Jul 06, 2015 at 10:17:32AM +0800, shannon.zhao@linaro.org wrote:
> >>>>From: Shannon Zhao <shannon.zhao@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@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@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.
> >>
> >
> >sorry, I don't feel this answers my question? ;)
> >
> 
> This index is only used for kvm_pmu_perf_overflow to locate the
> index of this PMU counter and kvm_pmu_perf_overflow will set the
> corresponding bit of overflow_status to show whether this counter
> overflows.
> 
> See patch 17/18:
> 
> +static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
> +				  struct perf_sample_data *data,
> +				  struct pt_regs *regs)
> +{
> +	struct kvm_pmc *pmc = perf_event->overflow_handler_context;
> +	struct kvm_vcpu *vcpu = pmc->vcpu;
> +	struct kvm_pmu *pmu = &vcpu->arch.pmu;
> +
> +	if (pmc->interrupt == true) {
> +		__set_bit(pmc->idx, (unsigned long *)&pmu->overflow_status);
> 
> >>>>+	u64 counter;
> >>>>+	u64 eventsel;
> >>>
> >>>does this map to PMEVTYPER<n>_EL0.evtCount?
> >>>
> >>No, it just stores the event type.
> >>
> >
> >can you specify more clearly what this maps to/how I derive its meaning?
> >
> >Is this a perf (Linux) event type number, or an architecturally defined
> >thing?
> >
> 
> Yes, it stores a perf event type number. This is used for
> kvm_pmu_set_counter_event_type to check whether event type of this
> time is same with the previous one. If they are same, it will return
> and doesn't create a new perf event for it and just reuses the
> previous one.
> 
> See PATCH 07/18:
> 
> +void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, unsigned
> long data,
> +				    unsigned long select_idx)
> +{
> +	struct kvm_pmu *pmu = &vcpu->arch.pmu;
> +	struct kvm_pmc *pmc = &pmu->pmc[select_idx];
> +	struct perf_event *event;
> +	struct perf_event_attr attr;
> +	unsigned config, type = PERF_TYPE_RAW;
> +
> +	if ((data & ARMV8_EVTYPE_EVENT) == pmc->eventsel)
> +		return;
> 

ok, thanks for the explanation of both:

I think it would be helpful, especially for the review, to have a
one-line comment on the struct definition, along the lines of:


struct kvm_pmc {
	u8 idx;		/* index into the pmu->pmc array */
	u64 eventsel;	/* perf event number, see ARMV8_EVTYPE_EVENT */
	...
};

Thanks,
-Christoffer

Patch

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.
+
 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@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;
+	u64 counter;
+	u64 eventsel;
+	bool interrupt;
+	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@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
+ * @vcpu: The vcpu pointer
+ *
+ * Initialize PMC and Set all the PMU IRQ numbers to invalid
+ * 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;
+}