[PATCH 08/16] KVM: arm64: Add tracepoint for failed MMIO guard check

[Marc Zyngier]

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

Signed-off-by: Marc Zyngier <m...@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

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