Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 45c5eb67 authored by Hollis Blanchard's avatar Hollis Blanchard Committed by Avi Kivity
Browse files

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



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: default avatarHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: default avatarJerone Young <jyoung5@us.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 3fe913e7

arch/powerpc/kvm/booke_guest.c

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "inst_emu",   VCPU_STAT(emulated_inst_exits) },

	{ "dec",        VCPU_STAT(dec_exits) },

	{ "ext_intr",   VCPU_STAT(ext_intr_exits) },

	{ "halt_wakeup", VCPU_STAT(halt_wakeup) },

	{ NULL }

};

arch/powerpc/kvm/powerpc.c

+17 −3
Original line number Diff line number Diff line
@@ -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;

}

include/asm-powerpc/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ struct kvm_vcpu_stat { 
	u32 emulated_inst_exits;

	u32 dec_exits;

	u32 ext_intr_exits;

	u32 halt_wakeup;

};



struct tlbe {

include/asm-powerpc/kvm_ppc.h

+5 −0
Original line number Diff line number Diff line
@@ -77,12 +77,17 @@ static inline void kvmppc_clear_exception(struct kvm_vcpu *vcpu, int exception) 
	clear_bit(priority, &vcpu->arch.pending_exceptions);

}



/* Helper function for "full" MSR writes. No need to call this if only EE is

 * changing. */

static inline void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)

{

	if ((new_msr & MSR_PR) != (vcpu->arch.msr & MSR_PR))

		kvmppc_mmu_priv_switch(vcpu, new_msr & MSR_PR);



	vcpu->arch.msr = new_msr;



	if (vcpu->arch.msr & MSR_WE)

		kvm_vcpu_block(vcpu);

}



#endif /* __POWERPC_KVM_PPC_H__ */