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Date:   Thu, 29 Jul 2021 19:56:30 +0000
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Subject: [PATCH 1/3] KVM: arm64: Record number of signal exits as a vCPU stat
From:   Oliver Upton <oupton@google.com>
To:     kvmarm@lists.cs.columbia.edu
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        Peter Shier <pshier@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        Guangyu Shi <guangyus@google.com>,
        Oliver Upton <oupton@google.com>,
        Jing Zhang <jingzhangos@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Most other architectures that implement KVM record a statistic
indicating the number of times a vCPU has exited due to a pending
signal. Add support for that stat to arm64.

Cc: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/arm64/include/asm/kvm_host.h | 1 +
 arch/arm64/kvm/arm.c              | 1 +
 arch/arm64/kvm/guest.c            | 3 ++-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 41911585ae0c..70e129f2b574 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -576,6 +576,7 @@ struct kvm_vcpu_stat {
 	u64 wfi_exit_stat;
 	u64 mmio_exit_user;
 	u64 mmio_exit_kernel;
+	u64 signal_exits;
 	u64 exits;
 };
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e9a2b8f27792..60d0a546d7fd 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -783,6 +783,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		if (signal_pending(current)) {
 			ret = -EINTR;
 			run->exit_reason = KVM_EXIT_INTR;
+			++vcpu->stat.signal_exits;
 		}
 
 		/*
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 1dfb83578277..50fc16ad872f 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -50,7 +50,8 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
 	STATS_DESC_COUNTER(VCPU, wfi_exit_stat),
 	STATS_DESC_COUNTER(VCPU, mmio_exit_user),
 	STATS_DESC_COUNTER(VCPU, mmio_exit_kernel),
-	STATS_DESC_COUNTER(VCPU, exits)
+	STATS_DESC_COUNTER(VCPU, exits),
+	STATS_DESC_COUNTER(VCPU, signal_exits),
 };
 static_assert(ARRAY_SIZE(kvm_vcpu_stats_desc) ==
 		sizeof(struct kvm_vcpu_stat) / sizeof(u64));
-- 
2.32.0.554.ge1b32706d8-goog