[PATCH v2 06/10] KVM: nVMX: Drop a superfluous WARN on reflecting EXTERNAL_INTERRUPT

From: Sean Christopherson
Date: Wed Apr 15 2020 - 13:57:03 EST


Drop the WARN in nested_vmx_reflect_vmexit() that fires if KVM attempts
to reflect an external interrupt. The WARN is blatantly impossible to
hit now that nested_vmx_l0_wants_exit() is called from
nested_vmx_reflect_vmexit() unconditionally returns true for
EXTERNAL_INTERRUPT.

Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index c2745cd9e022..e8db560ee3eb 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5863,12 +5863,11 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason)
return false;

/*
- * At this point, the exit interruption info in exit_intr_info
- * is only valid for EXCEPTION_NMI exits. For EXTERNAL_INTERRUPT
- * we need to query the in-kernel LAPIC.
+ * vmcs.VM_EXIT_INTR_INFO is only valid for EXCEPTION_NMI exits. For
+ * EXTERNAL_INTERRUPT, the value for vmcs12->vm_exit_intr_info would
+ * need to be synthesized by querying the in-kernel LAPIC, but external
+ * interrupts are never reflected to L1 so it's a non-issue.
*/
- WARN_ON(exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT);
-
if ((exit_intr_info &
(INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK)) ==
(INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK)) {
--
2.26.0