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

From: Paolo Bonzini
Date: Mon Sep 28 2015 - 06:44:35 EST


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@xxxxxxxxxx>
---
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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