On Sept. 20, 2018, Paolo Bonzini wrote: > On 11/09/2018 18:50, Liran Alon wrote: > > > > > > >> On 11 Sep 2018, at 16:16, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > >> > >> On 30/08/2018 11:57, Liran Alon wrote: > >>> Consider the case L1 had a IRQ/NMI event until it executed > >>> VMLAUNCH/VMRESUME which wasn't delivered because it was disallowed > >>> (e.g. interrupts disabled). When L1 executes VMLAUNCH/VMRESUME, > >>> L0 needs to evaluate if this pending event should cause an exit from > >>> L2 to L1 or delivered directly to L2 (e.g. In case L1 don't intercept > >>> EXTERNAL_INTERRUPT). > >>> > >>> Usually this would be handled by L0 requesting a IRQ/NMI window > >>> by setting VMCS accordingly. However, this setting was done on > >>> VMCS01 and now VMCS02 is active instead. Thus, when L1 executes > >>> VMLAUNCH/VMRESUME we force L0 to perform pending event evaluation by > >>> requesting a KVM_REQ_EVENT. > >>> > >>> Note that above scenario exists when L1 KVM is about to enter L2 but > >>> requests an "immediate-exit". As in this case, L1 will > >>> disable-interrupts and then send a self-IPI before entering L2. > >>> > >>> Co-authored-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > >>> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx> > >>> --- > >>> arch/x86/kvm/vmx.c | 25 ++++++++++++++++++++++++- > >>> 1 file changed, 24 insertions(+), 1 deletion(-) > >> > >> Any chance you can write a testcase for selftests/kvm? The framework > >> should be more or less stable by now. > >> > >> Paolo > > > > Actually, I have already written one and submitted it a week ago to the mailing list. > > You can find the relevant unit-tests here: > > https://patchwork.kernel.org/project/kvm/list/?series=14789 > > > The test doesn't pass with the new patch. > > Also, the patch that was applied lacks the final hunk: > > @@ -12702,7 +12724,8 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) > * by event injection, halt vcpu. > */ > if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) && > - !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK)) { > + !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) && > + !kvm_test_request(KVM_REQ_EVENT, vcpu)) { > vmx->nested.nested_run_pending = 0; > return kvm_vcpu_halt(vcpu); > } > > and the test doesn't pass even if I add this hunk. > (The v1 patch works, but it is a much bigger hammer). Anybody has time > to take a look? I tried to reproduce the failure - I ran both linked tests on Linux master (a83f87c1d2a93) but they pass. Can you post your failure log? Upstream kernel on an Ubuntu 18.04 with QEMU 2.11.1. The tests I ran: - vmx_pending_event_test - vmx_pending_event_hlt_test Nikita
