From: Shannon Zhao <redacted>

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 <redacted>
---
 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.

+
 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;

+	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