From: Vitaly Kuznetsov vkuznets@redhat.com
commit 99c221796a810055974b54c02e8f53297e48d146 upstream.
I noticed that apic test from kvm-unit-tests always hangs on my EPYC 7401P, the hanging test nmi-after-sti is trying to deliver 30000 NMIs and tracing shows that we're sometimes able to deliver a few but never all.
When we're trying to inject an NMI we may fail to do so immediately for various reasons, however, we still need to inject it so enable_nmi_window() arms nmi_singlestep mode. #DB occurs as expected, but we're not checking for pending NMIs before entering the guest and unless there's a different event to process, the NMI will never get delivered.
Make KVM_REQ_EVENT request on the vCPU from db_interception() to make sure pending NMIs are checked and possibly injected.
Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/svm.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2687,6 +2687,7 @@ static int npf_interception(struct vcpu_ static int db_interception(struct vcpu_svm *svm) { struct kvm_run *kvm_run = svm->vcpu.run; + struct kvm_vcpu *vcpu = &svm->vcpu;
if (!(svm->vcpu.guest_debug & (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) && @@ -2697,6 +2698,8 @@ static int db_interception(struct vcpu_s
if (svm->nmi_singlestep) { disable_nmi_singlestep(svm); + /* Make sure we check for pending NMIs upon entry */ + kvm_make_request(KVM_REQ_EVENT, vcpu); }
if (svm->vcpu.guest_debug &