linux-kernel - [FYI PATCH 05/20] KVM: x86: unify handling of interrupt window

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Message-Id: <1443436745-38086-6-git-send-email-pbonzini@redhat.com>
Date:	Mon, 28 Sep 2015 12:38:50 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:	bsd@...hat.com
Subject: [FYI PATCH 05/20] KVM: x86: unify handling of interrupt window

The interrupt window is currently checked twice, once in vmx.c/svm.c and
once in dm_request_for_irq_injection.  The only difference is the extra
check for kvm_arch_interrupt_allowed in dm_request_for_irq_injection,
and the different return value (EINTR/KVM_EXIT_INTR for vmx.c/svm.c vs.
0/KVM_EXIT_IRQ_WINDOW_OPEN for dm_request_for_irq_injection).

However, dm_request_for_irq_injection is basically dead code!  Revive it
by removing the checks in vmx.c and svm.c's vmexit handlers, and
fixing the returned values for the dm_request_for_irq_injection case.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm.c | 13 -------------
 arch/x86/kvm/vmx.c | 11 -----------
 arch/x86/kvm/x86.c |  4 ++--
 3 files changed, 2 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 89d278a0ad37..7d7bbe2651d2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3398,24 +3398,11 @@ static int msr_interception(struct vcpu_svm *svm)
 
 static int interrupt_window_interception(struct vcpu_svm *svm)
 {
-	struct kvm_run *kvm_run = svm->vcpu.run;
-
 	kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
 	svm_clear_vintr(svm);
 	svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
 	mark_dirty(svm->vmcb, VMCB_INTR);
 	++svm->vcpu.stat.irq_window_exits;
-	/*
-	 * If the user space waits to inject interrupts, exit as soon as
-	 * possible
-	 */
-	if (!lapic_in_kernel(&svm->vcpu) &&
-	    kvm_run->request_interrupt_window &&
-	    !kvm_cpu_has_interrupt(&svm->vcpu)) {
-		kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
-		return 0;
-	}
-
 	return 1;
 }
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d5b87be89631..90605f70a7d0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5524,17 +5524,6 @@ static int handle_interrupt_window(struct kvm_vcpu *vcpu)
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 
 	++vcpu->stat.irq_window_exits;
-
-	/*
-	 * If the user space waits to inject interrupts, exit as soon as
-	 * possible
-	 */
-	if (!lapic_in_kernel(vcpu) &&
-	    vcpu->run->request_interrupt_window &&
-	    !kvm_cpu_has_interrupt(vcpu)) {
-		vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
-		return 0;
-	}
 	return 1;
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e25bc4e2b7a9..080aaa7a4d91 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6473,8 +6473,8 @@ static int vcpu_run(struct kvm_vcpu *vcpu)
 			kvm_inject_pending_timer_irqs(vcpu);
 
 		if (dm_request_for_irq_injection(vcpu)) {
-			r = -EINTR;
-			vcpu->run->exit_reason = KVM_EXIT_INTR;
+			r = 0;
+			vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
 			++vcpu->stat.request_irq_exits;
 			break;
 		}
-- 
1.8.3.1


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