Commit eb41238c authored by Andrew Murray's avatar Andrew Murray Committed by Marc Zyngier
Browse files

arm64: KVM: Add accessors to track guest/host only counters 



In order to effeciently switch events_{guest,host} perf counters at
guest entry/exit we add bitfields to kvm_cpu_context for guest and host
events as well as accessors for updating them.

A function is also provided which allows the PMU driver to determine
if a counter should start counting when it is enabled. With exclude_host,
we may only start counting when entering the guest.

Signed-off-by: default avatarAndrew Murray <andrew.murray@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 630a1685

arch/arm64/include/asm/kvm_host.h

+17 −0
Original line number Diff line number Diff line
@@ -233,8 +233,14 @@ struct kvm_cpu_context { 
	struct kvm_vcpu *__hyp_running_vcpu;

};



struct kvm_pmu_events {

	u32 events_host;

	u32 events_guest;

};



struct kvm_host_data {

	struct kvm_cpu_context host_ctxt;

	struct kvm_pmu_events pmu_events;

};



typedef struct kvm_host_data kvm_host_data_t;
@@ -572,11 +578,22 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); 
void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);



static inline bool kvm_pmu_counter_deferred(struct perf_event_attr *attr)

{

	return attr->exclude_host;

}



#ifdef CONFIG_KVM /* Avoid conflicts with core headers if CONFIG_KVM=n */

static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)

{

	return kvm_arch_vcpu_run_map_fp(vcpu);

}



void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr);

void kvm_clr_pmu_events(u32 clr);

#else

static inline void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) {}

static inline void kvm_clr_pmu_events(u32 clr) {}

#endif



static inline void kvm_arm_vhe_guest_enter(void)

arch/arm64/kvm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o 
kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o

kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o

kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o

kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o fpsimd.o

kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o fpsimd.o pmu.o

kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/aarch32.o



kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic.o

arch/arm64/kvm/pmu.c

0 → 100644
+45 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright 2019 Arm Limited

 * Author: Andrew Murray <Andrew.Murray@arm.com>

 */

#include <linux/kvm_host.h>

#include <linux/perf_event.h>



/*

 * Given the exclude_{host,guest} attributes, determine if we are going

 * to need to switch counters at guest entry/exit.

 */

static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)

{

	/* Only switch if attributes are different */

	return (attr->exclude_host != attr->exclude_guest);

}



/*

 * Add events to track that we may want to switch at guest entry/exit

 * time.

 */

void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)

{

	struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);



	if (!kvm_pmu_switch_needed(attr))

		return;



	if (!attr->exclude_host)

		ctx->pmu_events.events_host |= set;

	if (!attr->exclude_guest)

		ctx->pmu_events.events_guest |= set;

}



/*

 * Stop tracking events

 */

void kvm_clr_pmu_events(u32 clr)

{

	struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);



	ctx->pmu_events.events_host &= ~clr;

	ctx->pmu_events.events_guest &= ~clr;

}

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