[PATCH v2 3/3] KVM: arm64: Add irq_exit counter for kvm_stat

[Yoan Picchi]

This counter is meant to detect when the guest vm exits due to an
interrupt. Those interrupts might be unrelated to the guest VM (say, some
network packet arrived, and such) but they still trigger an exit which is
recorded by the "exit" counter. The main purpose of this counter is to
give some more granularity to this base exit counter so that one can have
a rough idea of where those exits comes from and so, if those general
exits happen because of the host or of the guest.

Signed-off-by: Yoan Picchi <yoan.picchi at arm.com>
---
 arch/arm64/include/asm/kvm_host.h | 1 +
 arch/arm64/kvm/guest.c            | 1 +
 arch/arm64/kvm/handle_exit.c      | 1 +
 3 files changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 8f9d27571..185e707fb 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -565,6 +565,7 @@ struct kvm_vcpu_stat {
 	u64 mmio_exit_kernel;
 	u64 stage2_abort_exit;
 	u64 exits;
+	u64 irq_exits;
 };
 
 int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init);
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 41316b30e..eb4c24b7a 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -42,6 +42,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	VCPU_STAT("exits", exits),
 	VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
 	VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),
+	VCPU_STAT("irq_exits", irq_exits),
 	VM_STAT("regular_page_mapped", regular_page_mapped),
 	VM_STAT("huge_page_mapped", huge_page_mapped),
 	{ NULL }
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index cebe39f3b..7e5dbc5ff 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -244,6 +244,7 @@ int handle_exit(struct kvm_vcpu *vcpu, int exception_index)
 
 	switch (exception_index) {
 	case ARM_EXCEPTION_IRQ:
+		vcpu->stat.irq_exits++;
 		return 1;
 	case ARM_EXCEPTION_EL1_SERROR:
 		return 1;
-- 
2.17.1