From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: [patch 3/4] KVM: introduce irq_lock, use it to protect ioapic Date: Wed, 20 May 2009 15:48:44 -0300 Message-ID: <20090520185134.748295218@localhost.localdomain> References: <20090520184841.954066003@localhost.localdomain> Cc: Gregory Haskins , Marcelo Tosatti To: Avi Kivity , kvm@vger.kernel.org Return-path: Received: from mx2.redhat.com ([66.187.237.31]:50265 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754904AbZETSy6 (ORCPT ); Wed, 20 May 2009 14:54:58 -0400 Content-Disposition: inline; filename=ioapic-lock Sender: kvm-owner@vger.kernel.org List-ID: Subject says it all. Signed-off-by: Marcelo Tosatti Index: kvm-irqlock/include/linux/kvm_host.h =================================================================== --- kvm-irqlock.orig/include/linux/kvm_host.h +++ kvm-irqlock/include/linux/kvm_host.h @@ -123,7 +123,6 @@ struct kvm_kernel_irq_routing_entry { }; struct kvm { - struct mutex lock; /* protects the vcpus array and APIC accesses */ spinlock_t mmu_lock; struct rw_semaphore slots_lock; struct mm_struct *mm; /* userspace tied to this vm */ @@ -132,6 +131,12 @@ struct kvm { KVM_PRIVATE_MEM_SLOTS]; struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; struct list_head vm_list; + struct mutex lock; /* + * - protects mmio_bus, pio_bus. + * - protects a few concurrent ioctl's (FIXME). + * - protects concurrent create_vcpu, but + * kvm->vcpus walkers do it locklessly (FIXME). + */ struct kvm_io_bus mmio_bus; struct kvm_io_bus pio_bus; struct list_head irqfds; @@ -143,6 +148,7 @@ struct kvm { struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; #endif + struct mutex irq_lock; /* protects high level irq logic, ioapic */ #ifdef CONFIG_HAVE_KVM_IRQCHIP struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */ struct hlist_head mask_notifier_list; Index: kvm-irqlock/virt/kvm/ioapic.c =================================================================== --- kvm-irqlock.orig/virt/kvm/ioapic.c +++ kvm-irqlock/virt/kvm/ioapic.c @@ -225,6 +225,10 @@ static int ioapic_in_range(struct kvm_io { struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private; + /* + * Lockless check for ioapic->base_address on the hazy assumption + * it does not change during the lifetime of a VM. + */ return ((addr >= ioapic->base_address && (addr < ioapic->base_address + IOAPIC_MEM_LENGTH))); } @@ -238,6 +242,7 @@ static void ioapic_mmio_read(struct kvm_ 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: @@ -264,6 +269,7 @@ static void ioapic_mmio_read(struct kvm_ 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, @@ -275,6 +281,8 @@ static void ioapic_mmio_write(struct kvm 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 { @@ -300,6 +308,7 @@ static void ioapic_mmio_write(struct kvm default: break; } + mutex_unlock(&ioapic->kvm->irq_lock); } void kvm_ioapic_reset(struct kvm_ioapic *ioapic) Index: kvm-irqlock/virt/kvm/kvm_main.c =================================================================== --- kvm-irqlock.orig/virt/kvm/kvm_main.c +++ kvm-irqlock/virt/kvm/kvm_main.c @@ -985,6 +985,7 @@ static struct kvm *kvm_create_vm(void) kvm_io_bus_init(&kvm->pio_bus); INIT_LIST_HEAD(&kvm->irqfds); 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); --