linux-kernel - [PATCH] KVM: vmx: expose more information for KVM_INTERNAL_ERROR_DELIVERY

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Date:   Wed,  5 Jul 2017 12:38:44 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH] KVM: vmx: expose more information for KVM_INTERNAL_ERROR_DELIVERY_EV exits

This exit ended up being reported, but the currently exposed data does not provide
much of a starting point for debugging.  In the reported case, the vmexit was
an EPT misconfiguration (MMIO access).  Let userspace report ethe exit qualification
and, if relevant, the GPA.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6dcc4873e435..4be80c3ac24d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8408,9 +8408,15 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
 			exit_reason != EXIT_REASON_TASK_SWITCH)) {
 		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV;
-		vcpu->run->internal.ndata = 2;
+		vcpu->run->internal.ndata = 3;
 		vcpu->run->internal.data[0] = vectoring_info;
 		vcpu->run->internal.data[1] = exit_reason;
+		vcpu->run->internal.data[2] = vcpu->arch.exit_qualification;
+		if (exit_reason == EXIT_REASON_EPT_MISCONFIG) {
+			vcpu->run->internal.ndata++;
+			vcpu->run->internal.data[3] =
+				vmcs_read64(GUEST_PHYSICAL_ADDRESS);
+		}
 		return 0;
 	}
 
-- 
1.8.3.1