From 45405155d876c326da89162b8173b8cc9ab7ed75 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 7 Jun 2024 10:26:09 -0700 Subject: [PATCH] KVM: x86: WARN if a vCPU gets a valid wakeup that KVM can't yet inject WARN if a blocking vCPU is awakened by a valid wake event that KVM can't inject, e.g. because KVM needs to complete a nested VM-enter, or needs to re-inject an exception. For the nested VM-Enter case, KVM is supposed to clear "nested_run_pending" if L1 puts L2 into HLT, i.e. entering HLT "completes" the nested VM-Enter. And for already-injected exceptions, it should be impossible for the vCPU to be in a blocking state if a VM-Exit occurred while an exception was being vectored. Link: https://lore.kernel.org/r/20240607172609.3205077-7-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cacca83b06aa..aab69647c3b6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11208,7 +11208,10 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu) * causes a spurious wakeup from HLT). */ if (is_guest_mode(vcpu)) { - if (kvm_check_nested_events(vcpu) < 0) + int r = kvm_check_nested_events(vcpu); + + WARN_ON_ONCE(r == -EBUSY); + if (r < 0) return 0; } -- 2.49.0