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: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/include/asm-powerpc/kvm_ppc.h b/include/asm-powerpc/kvm_ppc.h
index 7ac8203..b35a7e3 100644
--- a/include/asm-powerpc/kvm_ppc.h
+++ b/include/asm-powerpc/kvm_ppc.h
@@ -77,12 +77,17 @@
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__ */