Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Marc Zyngier <maz@kernel.org>
To:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     will@kernel.org, qperret@google.com, dbrazdil@google.com,
        Srivatsa Vaddagiri <vatsa@codeaurora.org>,
        Shanker R Donthineni <sdonthineni@nvidia.com>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        kernel-team@android.com
Subject: [PATCH 08/16] KVM: arm64: Add tracepoint for failed MMIO guard check
Date:   Thu, 15 Jul 2021 17:31:51 +0100
Message-Id: <20210715163159.1480168-9-maz@kernel.org>
In-Reply-To: <20210715163159.1480168-1-maz@kernel.org>
References: <20210715163159.1480168-1-maz@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In order to make debugging easier, expose a new trace point
that triggers when a MMIO check fails.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/mmu.c       |  4 +++-
 arch/arm64/kvm/trace_arm.h | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 638827c8842b..c2a23457552b 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1229,8 +1229,10 @@ bool kvm_check_ioguard_page(struct kvm_vcpu *vcpu, gpa_t ipa)
 	ret = __check_ioguard_page(vcpu, ipa & PAGE_MASK);
 	spin_unlock(&vcpu->kvm->mmu_lock);
 
-	if (!ret)
+	if (!ret) {
+		trace_kvm_failed_mmio_check(*vcpu_pc(vcpu), ipa);
 		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
+	}
 
 	return ret;
 }
diff --git a/arch/arm64/kvm/trace_arm.h b/arch/arm64/kvm/trace_arm.h
index 33e4e7dd2719..e40cfeb251ad 100644
--- a/arch/arm64/kvm/trace_arm.h
+++ b/arch/arm64/kvm/trace_arm.h
@@ -89,6 +89,23 @@ TRACE_EVENT(kvm_access_fault,
 	TP_printk("IPA: %lx", __entry->ipa)
 );
 
+TRACE_EVENT(kvm_failed_mmio_check,
+	TP_PROTO(unsigned long vcpu_pc, unsigned long ipa),
+	TP_ARGS(vcpu_pc, ipa),
+
+	TP_STRUCT__entry(
+		__field(	unsigned long,	vcpu_pc		)
+		__field(	unsigned long,	ipa		)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_pc	= vcpu_pc;
+		__entry->ipa		= ipa;
+	),
+
+	TP_printk("PC: %lx IPA: %lx", __entry->vcpu_pc, __entry->ipa)
+);
+
 TRACE_EVENT(kvm_irq_line,
 	TP_PROTO(unsigned int type, int vcpu_idx, int irq_num, int level),
 	TP_ARGS(type, vcpu_idx, irq_num, level),
-- 
2.30.2