[PATCH v2] KVM: Factor out kvm_vcpu_kick to arch-generic code

[Christoffer Dall <c.dall@virtualopensystems.com>]

The kvm_vcpu_kick function performs roughly the same funcitonality on
most all architectures, so we shouldn't have separate copies.

PowerPC keeps a pointer to interchanging waitqueues on the vcpu_arch
structure and to accomodate this special need a
__KVM_HAVE_ARCH_VCPU_GET_WQ define and accompanying function
kvm_arch_vcpu_wq have been defined. For all other architectures this
is a generic inline that just returns &vcpu->wq;

This patch applies to Linus' tree on the Linux 3.3-rc1 tag.

Changes since v1:
 - Abstact CPU mode check into arch-specific function
 - Remove redundant vcpu->cpu assignment

Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
 arch/ia64/include/asm/kvm_host.h    |    1 +
 arch/ia64/kvm/kvm-ia64.c            |   16 ----------------
 arch/powerpc/include/asm/kvm_host.h |    6 ++++++
 arch/powerpc/kvm/powerpc.c          |   18 +++++++-----------
 arch/s390/kvm/kvm-s390.c            |    8 ++++++++
 arch/x86/kvm/x86.c                  |   17 ++---------------
 include/linux/kvm_host.h            |    9 +++++++++
 virt/kvm/kvm_main.c                 |   23 +++++++++++++++++++++++
 8 files changed, 56 insertions(+), 42 deletions(-)

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 2689ee5..06a5e91 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -365,6 +365,7 @@ struct thash_cb {
 };
 
 struct kvm_vcpu_stat {
+	u32 halt_wakeup;
 };
 
 struct kvm_vcpu_arch {
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 43f4c92..428eb0b 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1402,7 +1402,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	if (cpu != vcpu->cpu) {
-		vcpu->cpu = cpu;
 		if (vcpu->arch.ht_active)
 			kvm_migrate_hlt_timer(vcpu);
 	}
@@ -1851,21 +1850,6 @@ void kvm_arch_hardware_unsetup(void)
 {
 }
 
-void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
-{
-	int me;
-	int cpu = vcpu->cpu;
-
-	if (waitqueue_active(&vcpu->wq))
-		wake_up_interruptible(&vcpu->wq);
-
-	me = get_cpu();
-	if (cpu != me && (unsigned) cpu < nr_cpu_ids && cpu_online(cpu))
-		if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests))
-			smp_send_reschedule(cpu);
-	put_cpu();
-}
-
 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq)
 {
 	return __apic_accept_irq(vcpu, irq->vector);
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index bf8af5d..b687444 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -438,4 +438,10 @@ struct kvm_vcpu_arch {
 #define KVMPPC_VCPU_BUSY_IN_HOST	1
 #define KVMPPC_VCPU_RUNNABLE		2
 
+#define __KVM_HAVE_ARCH_VCPU_GET_WQ 1
+static inline wait_queue_head *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.wqp;
+}
+
 #endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 607fbdf..dd0c929 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -42,6 +42,11 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
 	       !!(v->arch.pending_exceptions);
 }
 
+int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
+}
+
 int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
 {
 	int nr = kvmppc_get_gpr(vcpu, 11);
@@ -311,10 +316,7 @@ static void kvmppc_decrementer_func(unsigned long data)
 
 	kvmppc_core_queue_dec(vcpu);
 
-	if (waitqueue_active(vcpu->arch.wqp)) {
-		wake_up_interruptible(vcpu->arch.wqp);
-		vcpu->stat.halt_wakeup++;
-	}
+	kvm_vcpu_kick(vcpu);
 }
 
 /*
@@ -363,7 +365,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	mtspr(SPRN_VRSAVE, vcpu->arch.vrsave);
 #endif
 	kvmppc_core_vcpu_load(vcpu, cpu);
-	vcpu->cpu = smp_processor_id();
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
@@ -572,12 +573,7 @@ int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq)
 
 	kvmppc_core_queue_external(vcpu, irq);
 
-	if (waitqueue_active(vcpu->arch.wqp)) {
-		wake_up_interruptible(vcpu->arch.wqp);
-		vcpu->stat.halt_wakeup++;
-	} else if (vcpu->cpu != -1) {
-		smp_send_reschedule(vcpu->cpu);
-	}
+	kvm_vcpu_kick(vcpu);
 
 	return 0;
 }
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index d1c44573..5e2217f 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -380,6 +380,14 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *vcpu)
+{
+	/* kvm common code refers to this, but never calls it */
+	BUG();
+	return 0;
+}
+
+
 static int kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
 {
 	kvm_s390_vcpu_initial_reset(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c38efd7..a1761ff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2252,7 +2252,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 		if (vcpu->cpu != cpu)
 			kvm_migrate_timers(vcpu);
-		vcpu->cpu = cpu;
 	}
 
 	accumulate_steal_time(vcpu);
@@ -6688,21 +6687,9 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 		 kvm_cpu_has_interrupt(vcpu));
 }
 
-void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *vcpu)
 {
-	int me;
-	int cpu = vcpu->cpu;
-
-	if (waitqueue_active(&vcpu->wq)) {
-		wake_up_interruptible(&vcpu->wq);
-		++vcpu->stat.halt_wakeup;
-	}
-
-	me = get_cpu();
-	if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
-		if (kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE)
-			smp_send_reschedule(cpu);
-	put_cpu();
+	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
 }
 
 int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d526231..b1339ee 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -407,6 +407,7 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot,
 			     gfn_t gfn);
 
 void kvm_vcpu_block(struct kvm_vcpu *vcpu);
+void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu);
 void kvm_resched(struct kvm_vcpu *vcpu);
 void kvm_load_guest_fpu(struct kvm_vcpu *vcpu);
@@ -474,6 +475,7 @@ int kvm_arch_hardware_setup(void);
 void kvm_arch_hardware_unsetup(void);
 void kvm_arch_check_processor_compat(void *rtn);
 int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu);
+int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *vcpu);
 
 void kvm_free_physmem(struct kvm *kvm);
 
@@ -489,6 +491,13 @@ static inline void kvm_arch_free_vm(struct kvm *kvm)
 }
 #endif
 
+#ifndef __KVM_HAVE_ARCH_VCPU_GET_WQ
+static inline wait_queue_head_t *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
+{
+	return &vcpu->wq;
+}
+#endif
+
 int kvm_arch_init_vm(struct kvm *kvm);
 void kvm_arch_destroy_vm(struct kvm *kvm);
 void kvm_free_all_assigned_devices(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d9cfb78..c9109bd 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -153,6 +153,7 @@ void vcpu_load(struct kvm_vcpu *vcpu)
 	cpu = get_cpu();
 	preempt_notifier_register(&vcpu->preempt_notifier);
 	kvm_arch_vcpu_load(vcpu, cpu);
+	vcpu->cpu = cpu;
 	put_cpu();
 }
 
@@ -1528,6 +1529,28 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 	finish_wait(&vcpu->wq, &wait);
 }
 
+/*
+ * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
+ */
+void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+{
+	int me;
+	int cpu = vcpu->cpu;
+	wait_queue_head_t *wqp;
+
+	wqp = kvm_arch_vcpu_wq(vcpu);
+	if (waitqueue_active(wqp)) {
+		wake_up_interruptible(wqp);
+		++vcpu->stat.halt_wakeup;
+	}
+
+	me = get_cpu();
+	if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
+		if (kvm_arch_vcpu_in_guest_mode(vcpu))
+			smp_send_reschedule(cpu);
+	put_cpu();
+}
+
 void kvm_resched(struct kvm_vcpu *vcpu)
 {
 	if (!need_resched())