linux-kernel - [PATCH 2/6] kvm: nVMX: move nested events check to kvm_vcpu

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Date:   Mon, 19 Dec 2016 17:17:08 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH 2/6] kvm: nVMX: move nested events check to kvm_vcpu_running

vcpu_run calls kvm_vcpu_running, not kvm_arch_vcpu_runnable,
and the former does not call check_nested_events.

Once KVM_REQ_EVENT is removed from the APICv interrupt injection
path, however, this would leave no place to trigger a vmexit
from L2 to L1, causing a missed interrupt delivery while in guest
mode.  This is caught by the "ack interrupt on exit" test in
vmx.flat.

[This does not change the calls to check_nested_events in
 inject_pending_event.  That is material for a separate cleanup.]

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/x86.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d5a5fc2f8758..32e5f54a8eba 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6920,6 +6920,9 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
 
 static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
 {
+	if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events)
+		kvm_x86_ops->check_nested_events(vcpu, false);
+
 	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
 		!vcpu->arch.apf.halted);
 }
@@ -8286,9 +8289,6 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 {
-	if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events)
-		kvm_x86_ops->check_nested_events(vcpu, false);
-
 	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
 }
 
-- 
1.8.3.1