linux-kernel - [PATCH v4 33/34] KVM: selftests: Print out guest RIP on unhandled exception

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Date:   Fri, 28 Jul 2023 17:36:42 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Thomas Huth <thuth@...hat.com>,
        "Philippe Mathieu-Daudé" <philmd@...aro.org>,
        Aaron Lewis <aaronlewis@...gle.com>
Subject: [PATCH v4 33/34] KVM: selftests: Print out guest RIP on unhandled exception

Use the newfanged printf-based guest assert framework to spit out the
guest RIP when an unhandled exception is detected, which makes debugging
such failures *much* easier.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 .../selftests/kvm/lib/x86_64/processor.c       | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index d4a0b504b1e0..d8288374078e 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1074,11 +1074,6 @@ static bool kvm_fixup_exception(struct ex_regs *regs)
 	return true;
 }
 
-void kvm_exit_unexpected_vector(uint32_t value)
-{
-	ucall(UCALL_UNHANDLED, 1, value);
-}
-
 void route_exception(struct ex_regs *regs)
 {
 	typedef void(*handler)(struct ex_regs *);
@@ -1092,7 +1087,10 @@ void route_exception(struct ex_regs *regs)
 	if (kvm_fixup_exception(regs))
 		return;
 
-	kvm_exit_unexpected_vector(regs->vector);
+	ucall_assert(UCALL_UNHANDLED,
+		     "Unhandled exception in guest", __FILE__, __LINE__,
+		     "Unhandled exception '0x%lx' at guest RIP '0x%lx'",
+		     regs->vector, regs->rip);
 }
 
 void vm_init_descriptor_tables(struct kvm_vm *vm)
@@ -1135,12 +1133,8 @@ void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
 {
 	struct ucall uc;
 
-	if (get_ucall(vcpu, &uc) == UCALL_UNHANDLED) {
-		uint64_t vector = uc.args[0];
-
-		TEST_FAIL("Unexpected vectored event in guest (vector:0x%lx)",
-			  vector);
-	}
+	if (get_ucall(vcpu, &uc) == UCALL_UNHANDLED)
+		REPORT_GUEST_ASSERT(uc);
 }
 
 const struct kvm_cpuid_entry2 *get_cpuid_entry(const struct kvm_cpuid2 *cpuid,
-- 
2.41.0.487.g6d72f3e995-goog