KVM: nVMX: Make an event request if INIT or SIPI is pending on VM-Enter

Evaluate interrupts, i.e. set KVM_REQ_EVENT, if INIT or SIPI is pending
when emulating nested VM-Enter.  INIT is blocked while the CPU is in VMX
root mode, but not in VMX non-root, i.e. becomes unblocked on VM-Enter.
This bug has been masked by KVM calling ->check_nested_events() in the
core run loop, but that hack will be fixed in the near future.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220921003201.1441511-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3a08005..5922531 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3377,6 +3377,8 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
                (CPU_BASED_INTR_WINDOW_EXITING | CPU_BASED_NMI_WINDOW_EXITING);
        if (likely(!evaluate_pending_interrupts) && kvm_vcpu_apicv_active(vcpu))
                evaluate_pending_interrupts |= vmx_has_apicv_interrupt(vcpu);
+       if (!evaluate_pending_interrupts)
+               evaluate_pending_interrupts |= kvm_apic_has_pending_init_or_sipi(vcpu);
 
        if (!vmx->nested.nested_run_pending ||
            !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
@@ -3457,18 +3459,10 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
        }
 
        /*
-        * If L1 had a pending IRQ/NMI until it executed
-        * VMLAUNCH/VMRESUME which wasn't delivered because it was
-        * disallowed (e.g. interrupts disabled), 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 the processor noticing an
-        * IRQ/NMI window request, or checking RVI during evaluation of
-        * pending virtual interrupts.  However, this setting was done
-        * on VMCS01 and now VMCS02 is active instead. Thus, we force L0
-        * to perform pending event evaluation by requesting a KVM_REQ_EVENT.
+        * Re-evaluate pending events if L1 had a pending IRQ/NMI/INIT/SIPI
+        * when it executed VMLAUNCH/VMRESUME, as entering non-root mode can
+        * effectively unblock various events, e.g. INIT/SIPI cause VM-Exit
+        * unconditionally.
         */
        if (unlikely(evaluate_pending_interrupts))
                kvm_make_request(KVM_REQ_EVENT, vcpu);