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KVM: ppc: Handle guest idle by emulating MSR[WE] writes

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This reduces host CPU usage when the guest is idle. However, the guest must
set MSR[WE] in its idle loop, which Linux did not do until 2.6.26.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Hollis Blanchard
2008-04-25 17:55:49 -05:00
committed by Avi Kivity
parent 3fe913e7c5
commit 45c5eb67da
4 changed files with 24 additions and 3 deletions
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20
arch/powerpc/kvm/powerpc.c
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@@ -36,13 +36,12 @@ gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
{
/* XXX implement me */
return 0;
return !!(v->arch.pending_exceptions);
}
int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
{
return 1;
return !(v->arch.msr & MSR_WE);
}
@@ -214,6 +213,11 @@ static void kvmppc_decrementer_func(unsigned long data)
struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;
kvmppc_queue_exception(vcpu, BOOKE_INTERRUPT_DECREMENTER);
if (waitqueue_active(&vcpu->wq)) {
wake_up_interruptible(&vcpu->wq);
vcpu->stat.halt_wakeup++;
}
}
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
@@ -339,6 +343,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
int r;
sigset_t sigsaved;
vcpu_load(vcpu);
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
@@ -363,12 +369,20 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
vcpu_put(vcpu);
return r;
}
int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq)
{
kvmppc_queue_exception(vcpu, BOOKE_INTERRUPT_EXTERNAL);
if (waitqueue_active(&vcpu->wq)) {
wake_up_interruptible(&vcpu->wq);
vcpu->stat.halt_wakeup++;
}
return 0;
}