[PATCH RFC 02/21] KVM: x86: check against irqchip_mode in kvm_set_routing_entry()

[David Hildenbrand <david@redhat.com>]

Let's replace the checks for pic_in_kernel() and ioapic_in_kernel() by
checks against irqchip_mode. Add another state, indicating that the
caller is currently initializing the irqchip.

This is necessary to switch pic_in_kernel() and ioapic_in_kernel() to
irqchip_mode, too.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/irq.h              | 8 +++++++-
 arch/x86/kvm/irq_comm.c         | 8 ++------
 arch/x86/kvm/x86.c              | 2 ++
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 74ef58c..c8cdcc3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -727,6 +727,7 @@ struct kvm_hv {
 
 enum kvm_irqchip_mode {
 	KVM_IRQCHIP_NONE,
+	KVM_IRQCHIP_KERNEL_INIT,  /* KVM_CREATE_IRQCHIP in progress */
 	KVM_IRQCHIP_KERNEL,       /* created with KVM_CREATE_IRQCHIP */
 	KVM_IRQCHIP_SPLIT,        /* created with KVM_CAP_SPLIT_IRQCHIP */
 };
diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index 40d5b2c..9ebb6f5 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -96,6 +96,11 @@ static inline int irqchip_split(struct kvm *kvm)
 	return kvm->arch.irqchip_mode == KVM_IRQCHIP_SPLIT;
 }
 
+static inline int irqchip_kernel_init(struct kvm *kvm)
+{
+	return kvm->arch.irqchip_mode == KVM_IRQCHIP_KERNEL_INIT;
+}
+
 static inline int irqchip_kernel(struct kvm *kvm)
 {
 	return kvm->arch.irqchip_mode == KVM_IRQCHIP_KERNEL;
@@ -103,7 +108,8 @@ static inline int irqchip_kernel(struct kvm *kvm)
 
 static inline int irqchip_in_kernel(struct kvm *kvm)
 {
-	bool ret = kvm->arch.irqchip_mode != KVM_IRQCHIP_NONE;
+	bool ret = kvm->arch.irqchip_mode == KVM_IRQCHIP_KERNEL ||
+		   kvm->arch.irqchip_mode == KVM_IRQCHIP_SPLIT;
 
 	/* Matches with wmb after initializing kvm->irq_routing. */
 	smp_rmb();
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index b96d389..4e4a67a 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -282,22 +282,18 @@ int kvm_set_routing_entry(struct kvm *kvm,
 
 	switch (ue->type) {
 	case KVM_IRQ_ROUTING_IRQCHIP:
+		if (!irqchip_kernel(kvm) && !irqchip_kernel_init(kvm))
+			goto out;
 		delta = 0;
 		switch (ue->u.irqchip.irqchip) {
 		case KVM_IRQCHIP_PIC_SLAVE:
 			delta = 8;
 			/* fall through */
 		case KVM_IRQCHIP_PIC_MASTER:
-			if (!pic_in_kernel(kvm))
-				goto out;
-
 			e->set = kvm_set_pic_irq;
 			max_pin = PIC_NUM_PINS;
 			break;
 		case KVM_IRQCHIP_IOAPIC:
-			if (!ioapic_in_kernel(kvm))
-				goto out;
-
 			max_pin = KVM_IOAPIC_NUM_PINS;
 			e->set = kvm_set_ioapic_irq;
 			break;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b2a4b11..c69940c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4022,8 +4022,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 			goto create_irqchip_unlock;
 		}
 
+		kvm->arch.irqchip_mode = KVM_IRQCHIP_KERNEL_INIT;
 		r = kvm_setup_default_irq_routing(kvm);
 		if (r) {
+			kvm->arch.irqchip_mode = KVM_IRQCHIP_NONE;
 			mutex_lock(&kvm->slots_lock);
 			mutex_lock(&kvm->irq_lock);
 			kvm_ioapic_destroy(kvm);
-- 
2.9.3