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/arch/powerpc/kvm/booke_guest.c b/arch/powerpc/kvm/booke_guest.c
index 6d9884a..b3db6f4 100644
--- a/arch/powerpc/kvm/booke_guest.c
+++ b/arch/powerpc/kvm/booke_guest.c
@@ -49,6 +49,7 @@
{ "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 }
};
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index bad40bd..777e0f3 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -36,13 +36,12 @@
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 @@
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 r;
sigset_t sigsaved;
+ vcpu_load(vcpu);
+
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
@@ -363,12 +369,20 @@
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;
}
diff --git a/include/asm-powerpc/kvm_host.h b/include/asm-powerpc/kvm_host.h
index 04ffbb8..81a69d7 100644
--- a/include/asm-powerpc/kvm_host.h
+++ b/include/asm-powerpc/kvm_host.h
@@ -59,6 +59,7 @@
u32 emulated_inst_exits;
u32 dec_exits;
u32 ext_intr_exits;
+ u32 halt_wakeup;
};
struct tlbe {
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__ */