KVM: introduce irq_lock, use it to protect ioapic

Introduce irq_lock, and use to protect ioapic data structures.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

include/linux/kvm_host.h

@@ -124,7 +124,6 @@ struct kvm_kernel_irq_routing_entry {
 };
 
 struct kvm {
-	struct mutex lock; /* protects the vcpus array and APIC accesses */
 	spinlock_t mmu_lock;
 	spinlock_t requests_lock;
 	struct rw_semaphore slots_lock;
@@ -134,6 +133,7 @@ struct kvm {
 					KVM_PRIVATE_MEM_SLOTS];
 	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
 	struct list_head vm_list;
+	struct mutex lock;
 	struct kvm_io_bus mmio_bus;
 	struct kvm_io_bus pio_bus;
 #ifdef CONFIG_HAVE_KVM_EVENTFD
@@ -150,6 +150,7 @@ struct kvm {
 	struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
 #endif
 
+	struct mutex irq_lock;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
 	struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */
 	struct hlist_head mask_notifier_list;

virt/kvm/ioapic.c

@@ -243,6 +243,7 @@ static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 	ioapic_debug("addr %lx\n", (unsigned long)addr);
 	ASSERT(!(addr & 0xf));	/* check alignment */
 
+	mutex_lock(&ioapic->kvm->irq_lock);
 	addr &= 0xff;
 	switch (addr) {
 	case IOAPIC_REG_SELECT:
@@ -269,6 +270,7 @@ static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 	default:
 		printk(KERN_WARNING "ioapic: wrong length %d\n", len);
 	}
+	mutex_unlock(&ioapic->kvm->irq_lock);
 }
 
 static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
@@ -280,6 +282,8 @@ static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 	ioapic_debug("ioapic_mmio_write addr=%p len=%d val=%p\n",
 		     (void*)addr, len, val);
 	ASSERT(!(addr & 0xf));	/* check alignment */
+
+	mutex_lock(&ioapic->kvm->irq_lock);
 	if (len == 4 || len == 8)
 		data = *(u32 *) val;
 	else {
@@ -305,6 +309,7 @@ static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 	default:
 		break;
 	}
+	mutex_unlock(&ioapic->kvm->irq_lock);
 }
 
 void kvm_ioapic_reset(struct kvm_ioapic *ioapic)

virt/kvm/kvm_main.c

@@ -982,6 +982,7 @@ static struct kvm *kvm_create_vm(void)
 	kvm_io_bus_init(&kvm->pio_bus);
 	kvm_irqfd_init(kvm);
 	mutex_init(&kvm->lock);
+	mutex_init(&kvm->irq_lock);
 	kvm_io_bus_init(&kvm->mmio_bus);
 	init_rwsem(&kvm->slots_lock);
 	atomic_set(&kvm->users_count, 1);