KVM: VMX: Use vmx_interrupt_blocked() directly from vmx_handle_exit()

Use vmx_interrupt_blocked() instead of bouncing through
vmx_interrupt_allowed() when handling edge cases in vmx_handle_exit().
The nested_run_pending check in vmx_interrupt_allowed() should never
evaluate true in the VM-Exit path.

Hoist the WARN in handle_invalid_guest_state() up to vmx_handle_exit()
to enforce the above assumption for the !enable_vnmi case, and to detect
any other potential bugs with nested VM-Enter.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-12-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a5140ed..50a2e46 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5285,18 +5285,11 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
        bool intr_window_requested;
        unsigned count = 130;
 
-       /*
-        * We should never reach the point where we are emulating L2
-        * due to invalid guest state as that means we incorrectly
-        * allowed a nested VMEntry with an invalid vmcs12.
-        */
-       WARN_ON_ONCE(vmx->emulation_required && vmx->nested.nested_run_pending);
-
        intr_window_requested = exec_controls_get(vmx) &
                                CPU_BASED_INTR_WINDOW_EXITING;
 
        while (vmx->emulation_required && count-- != 0) {
-               if (intr_window_requested && vmx_interrupt_allowed(vcpu))
+               if (intr_window_requested && !vmx_interrupt_blocked(vcpu))
                        return handle_interrupt_window(&vmx->vcpu);
 
                if (kvm_test_request(KVM_REQ_EVENT, vcpu))
@@ -5913,6 +5906,14 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
        if (enable_pml)
                vmx_flush_pml_buffer(vcpu);
 
+       /*
+        * We should never reach this point with a pending nested VM-Enter, and
+        * more specifically emulation of L2 due to invalid guest state (see
+        * below) should never happen as that means we incorrectly allowed a
+        * nested VM-Enter with an invalid vmcs12.
+        */
+       WARN_ON_ONCE(vmx->nested.nested_run_pending);
+
        /* If guest state is invalid, start emulating */
        if (vmx->emulation_required)
                return handle_invalid_guest_state(vcpu);
@@ -5979,7 +5980,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
 
        if (unlikely(!enable_vnmi &&
                     vmx->loaded_vmcs->soft_vnmi_blocked)) {
-               if (vmx_interrupt_allowed(vcpu)) {
+               if (!vmx_interrupt_blocked(vcpu)) {
                        vmx->loaded_vmcs->soft_vnmi_blocked = 0;
                } else if (vmx->loaded_vmcs->vnmi_blocked_time > 1000000000LL &&
                           vcpu->arch.nmi_pending) {