On 03/12/15 06:11, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> 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.
>
> Since this only supports ARM64 (or PMUv3), add a separate config symbol
> for it.
>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 2 ++
> arch/arm64/kvm/Kconfig | 8 ++++++++
> include/kvm/arm_pmu.h | 41 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 51 insertions(+)
> create mode 100644 include/kvm/arm_pmu.h
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index a35ce72..42e15bb 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -37,6 +37,7 @@
>
> #include <kvm/arm_vgic.h>
> #include <kvm/arm_arch_timer.h>
> +#include <kvm/arm_pmu.h>
>
> #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS
>
> @@ -132,6 +133,7 @@ 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/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index a5272c0..66da9a2 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -36,6 +36,7 @@ config KVM
> select HAVE_KVM_EVENTFD
> select HAVE_KVM_IRQFD
> select KVM_ARM_VGIC_V3
> + select KVM_ARM_PMU
> ---help---
> Support hosting virtualized guest machines.
> We don't support KVM with 16K page tables yet, due to the multiple
> @@ -48,6 +49,13 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> +config KVM_ARM_PMU
> + bool
> + depends on KVM_ARM_HOST && HW_PERF_EVENTS
> + ---help---
> + Adds support for a virtual Performance Monitoring Unit (PMU) in
> + virtual machines.
> +
> source drivers/vhost/Kconfig
>
> endif # VIRTUALIZATION
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> new file mode 100644
> index 0000000..0c13470
> --- /dev/null
> +++ b/include/kvm/arm_pmu.h
> @@ -0,0 +1,41 @@
> +/*
> + * Copyright (C) 2015 Linaro Ltd.
> + * Author: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> + *
> + * 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 <linux/perf_event.h>
> +#ifdef CONFIG_KVM_ARM_PMU
> +#include <asm/pmu.h>
> +#endif
> +
> +struct kvm_pmc {
> + u8 idx;/* index into the pmu->pmc array */
> + struct perf_event *perf_event;
> + struct kvm_vcpu *vcpu;
Why do you need this? If you have the pointer to a kvm_pmc structure, it
is very cheap to compute the address of the vcpu:
static inline kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu;
pmc -= pmc->idx;
pmu = container_of(pmc, struct kvm_pmu, pmc);
return container_of(pmu, struct kvm_vcpu, pmu);
}
All of which the compiler will happily optimize for you.
> + u64 bitmask;
Looking at the code in pmu.c, there seem to be some confusion between
u64 and unsigned long (see kvm_pmu_get_counter_value). Please make sure
this is uniform.
> +};
> +
> +struct kvm_pmu {
> +#ifdef CONFIG_KVM_ARM_PMU
> + /* PMU IRQ Number per VCPU */
> + int irq_num;
> + struct kvm_pmc pmc[ARMV8_MAX_COUNTERS];
> +#endif
> +};
> +
> +#endif
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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