KVM: nSVM: clear events pending from svm_complete_interrupts() when exiting to L1

kvm-unit-tests' eventinj "NMI failing on IDT" test results in NMI being
delivered to the host (L1) when it's running nested. The problem seems to
be: svm_complete_interrupts() raises 'nmi_injected' flag but later we
decide to reflect EXIT_NPF to L1. The flag remains pending and we do NMI
injection upon entry so it got delivered to L1 instead of L2.

It seems that VMX code solves the same issue in prepare_vmcs12(), this was
introduced with code refactoring in commit c69f4060ea7b ("KVM: nVMX: Rework
event injection and recovery").

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8a0c9a1f6ac8a4e4e7e68e696a297cdd533f2dfe..9caf1252c64aeb976b7e27da5d209ced30f278e3 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3414,6 +3414,14 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
        kvm_mmu_reset_context(&svm->vcpu);
        kvm_mmu_load(&svm->vcpu);
 
+       /*
+        * Drop what we picked up for L2 via svm_complete_interrupts() so it
+        * doesn't end up in L1.
+        */
+       svm->vcpu.arch.nmi_injected = false;
+       kvm_clear_exception_queue(&svm->vcpu);
+       kvm_clear_interrupt_queue(&svm->vcpu);
+
        return 0;
 }