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

From: Sean Christopherson
Date: Fri Jul 28 2023 - 20:41:00 EST


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@xxxxxxxxxx>
---
.../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