Marcelo Tosatti wrote: > Switch irq injection/acking to irq_lock, and change PIO/MMIO paths > so that the device search is protected by kvm->lock, but not the > read/write callbacks (which is responsability of the device). > > Fix for http://article.gmane.org/gmane.comp.emulators.kvm.devel/32286. > > Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> > > Index: kvm/arch/x86/kvm/i8254.c > =================================================================== > --- kvm.orig/arch/x86/kvm/i8254.c > +++ kvm/arch/x86/kvm/i8254.c > @@ -634,10 +634,10 @@ static void __inject_pit_timer_intr(stru > struct kvm_vcpu *vcpu; > int i; > > - mutex_lock(&kvm->lock); > + mutex_lock(&kvm->irq_lock); > There would be advantages to having irq_lock be interrupt/nonpreempt-friendly design, such as s/mutex/spinlock. For instance, irqfd could inject the interrupt directly without deferring to a workqueue. I'm not sure if this is possible/easy, but its something to consider. -Greg > kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1); > kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0); > - mutex_unlock(&kvm->lock); > + mutex_unlock(&kvm->irq_lock); > > /* > * Provides NMI watchdog support via Virtual Wire mode. > Index: kvm/arch/x86/kvm/x86.c > =================================================================== > --- kvm.orig/arch/x86/kvm/x86.c > +++ kvm/arch/x86/kvm/x86.c > @@ -1909,10 +1909,10 @@ long kvm_arch_vm_ioctl(struct file *filp > goto out; > if (irqchip_in_kernel(kvm)) { > __s32 status; > - mutex_lock(&kvm->lock); > + mutex_lock(&kvm->irq_lock); > status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, > irq_event.irq, irq_event.level); > - mutex_unlock(&kvm->lock); > + mutex_unlock(&kvm->irq_lock); > if (ioctl == KVM_IRQ_LINE_STATUS) { > irq_event.status = status; > if (copy_to_user(argp, &irq_event, > @@ -2158,12 +2158,11 @@ mmio: > */ > mutex_lock(&vcpu->kvm->lock); > mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0); > + mutex_unlock(&vcpu->kvm->lock); > if (mmio_dev) { > kvm_iodevice_read(mmio_dev, gpa, bytes, val); > - mutex_unlock(&vcpu->kvm->lock); > return X86EMUL_CONTINUE; > } > - mutex_unlock(&vcpu->kvm->lock); > > vcpu->mmio_needed = 1; > > vcpu->mmio_phys_addr = gpa; > @@ -2541,7 +2540,6 @@ static void kernel_pio(struct kvm_io_dev > { > /* TODO: String I/O for in kernel device */ > > - mutex_lock(&vcpu->kvm->lock); > if (vcpu->arch.pio.in) > kvm_iodevice_read(pio_dev, vcpu->arch.pio.port, > vcpu->arch.pio.size, > @@ -2550,7 +2548,6 @@ static void kernel_pio(struct kvm_io_dev > kvm_iodevice_write(pio_dev, vcpu->arch.pio.port, > vcpu->arch.pio.size, > pd); > - mutex_unlock(&vcpu->kvm->lock); > } > > static void pio_string_write(struct kvm_io_device *pio_dev, > @@ -2560,14 +2557,12 @@ static void pio_string_write(struct kvm_ > void *pd = vcpu->arch.pio_data; > int i; > > - mutex_lock(&vcpu->kvm->lock); > for (i = 0; i < io->cur_count; i++) { > kvm_iodevice_write(pio_dev, io->port, > io->size, > pd); > pd += io->size; > } > - mutex_unlock(&vcpu->kvm->lock); > } > > static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu, > @@ -2604,7 +2599,9 @@ int kvm_emulate_pio(struct kvm_vcpu *vcp > val = kvm_register_read(vcpu, VCPU_REGS_RAX); > memcpy(vcpu->arch.pio_data, &val, 4); > > + mutex_lock(&vcpu->kvm->lock); > pio_dev = vcpu_find_pio_dev(vcpu, port, size, !in); > + mutex_unlock(&vcpu->kvm->lock); > if (pio_dev) { > kernel_pio(pio_dev, vcpu, vcpu->arch.pio_data); > complete_pio(vcpu); > @@ -2668,9 +2665,11 @@ int kvm_emulate_pio_string(struct kvm_vc > > vcpu->arch.pio.guest_gva = address; > > + mutex_lock(&vcpu->kvm->lock); > pio_dev = vcpu_find_pio_dev(vcpu, port, > vcpu->arch.pio.cur_count, > !vcpu->arch.pio.in); > + mutex_unlock(&vcpu->kvm->lock); > if (!vcpu->arch.pio.in) { > /* string PIO write */ > ret = pio_copy_data(vcpu); > Index: kvm/virt/kvm/kvm_main.c > =================================================================== > --- kvm.orig/virt/kvm/kvm_main.c > +++ kvm/virt/kvm/kvm_main.c > @@ -62,6 +62,12 @@ > MODULE_AUTHOR("Qumranet"); > MODULE_LICENSE("GPL"); > > +/* > + * Ordering of locks: > + * > + * kvm->lock --> kvm->irq_lock > + */ > + > DEFINE_SPINLOCK(kvm_lock); > LIST_HEAD(vm_list); > > @@ -126,11 +132,7 @@ static void kvm_assigned_dev_interrupt_w > interrupt_work); > kvm = assigned_dev->kvm; > > - /* This is taken to safely inject irq inside the guest. When > - * the interrupt injection (or the ioapic code) uses a > - * finer-grained lock, update this > - */ > - mutex_lock(&kvm->lock); > + mutex_lock(&kvm->irq_lock); > spin_lock_irq(&assigned_dev->assigned_dev_lock); > if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) { > struct kvm_guest_msix_entry *guest_entries = > @@ -159,7 +161,7 @@ static void kvm_assigned_dev_interrupt_w > } > > spin_unlock_irq(&assigned_dev->assigned_dev_lock); > - mutex_unlock(&assigned_dev->kvm->lock); > + mutex_unlock(&assigned_dev->kvm->irq_lock); > } > > static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id) > @@ -215,7 +217,7 @@ static void kvm_assigned_dev_ack_irq(str > static void deassign_guest_irq(struct kvm *kvm, > struct kvm_assigned_dev_kernel *assigned_dev) > { > - kvm_unregister_irq_ack_notifier(&assigned_dev->ack_notifier); > + kvm_unregister_irq_ack_notifier(kvm, &assigned_dev->ack_notifier); > assigned_dev->ack_notifier.gsi = -1; > > if (assigned_dev->irq_source_id != -1) > Index: kvm/virt/kvm/irq_comm.c > =================================================================== > --- kvm.orig/virt/kvm/irq_comm.c > +++ kvm/virt/kvm/irq_comm.c > @@ -62,6 +62,8 @@ int kvm_irq_delivery_to_apic(struct kvm > int i, r = -1; > struct kvm_vcpu *vcpu, *lowest = NULL; > > + WARN_ON(!mutex_is_locked(&kvm->irq_lock)); > + > if (irq->dest_mode == 0 && irq->dest_id == 0xff && > kvm_is_dm_lowest_prio(irq)) > printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n"); > @@ -113,7 +115,7 @@ static int kvm_set_msi(struct kvm_kernel > return kvm_irq_delivery_to_apic(kvm, NULL, &irq); > } > > -/* This should be called with the kvm->lock mutex held > +/* This should be called with the kvm->irq_lock mutex held > * Return value: > * < 0 Interrupt was ignored (masked or not delivered for other reasons) > * = 0 Interrupt was coalesced (previous irq is still pending) > @@ -125,6 +127,8 @@ int kvm_set_irq(struct kvm *kvm, int irq > unsigned long *irq_state, sig_level; > int ret = -1; > > + WARN_ON(!mutex_is_locked(&kvm->irq_lock)); > + > if (irq < KVM_IOAPIC_NUM_PINS) { > irq_state = (unsigned long *)&kvm->arch.irq_states[irq]; > > @@ -174,19 +178,26 @@ void kvm_notify_acked_irq(struct kvm *kv > void kvm_register_irq_ack_notifier(struct kvm *kvm, > struct kvm_irq_ack_notifier *kian) > { > + mutex_lock(&kvm->irq_lock); > hlist_add_head(&kian->link, &kvm->arch.irq_ack_notifier_list); > + mutex_unlock(&kvm->irq_lock); > } > > -void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian) > +void kvm_unregister_irq_ack_notifier(struct kvm *kvm, > + struct kvm_irq_ack_notifier *kian) > { > + mutex_lock(&kvm->irq_lock); > hlist_del_init(&kian->link); > + mutex_unlock(&kvm->irq_lock); > } > > -/* The caller must hold kvm->lock mutex */ > int kvm_request_irq_source_id(struct kvm *kvm) > { > unsigned long *bitmap = &kvm->arch.irq_sources_bitmap; > - int irq_source_id = find_first_zero_bit(bitmap, > + int irq_source_id; > + > + mutex_lock(&kvm->irq_lock); > + irq_source_id = find_first_zero_bit(bitmap, > sizeof(kvm->arch.irq_sources_bitmap)); > > if (irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) { > @@ -196,6 +207,7 @@ int kvm_request_irq_source_id(struct kvm > > ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID); > set_bit(irq_source_id, bitmap); > + mutex_unlock(&kvm->irq_lock); > > return irq_source_id; > } > @@ -206,6 +218,7 @@ void kvm_free_irq_source_id(struct kvm * > > ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID); > > + mutex_lock(&kvm->irq_lock); > if (irq_source_id < 0 || > irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) { > printk(KERN_ERR "kvm: IRQ source ID out of range!\n"); > @@ -214,19 +227,24 @@ void kvm_free_irq_source_id(struct kvm * > for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++) > clear_bit(irq_source_id, &kvm->arch.irq_states[i]); > clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap); > + mutex_unlock(&kvm->irq_lock); > } > > void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq, > struct kvm_irq_mask_notifier *kimn) > { > + mutex_lock(&kvm->irq_lock); > kimn->irq = irq; > hlist_add_head(&kimn->link, &kvm->mask_notifier_list); > + mutex_unlock(&kvm->irq_lock); > } > > void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq, > struct kvm_irq_mask_notifier *kimn) > { > + mutex_lock(&kvm->irq_lock); > hlist_del(&kimn->link); > + mutex_unlock(&kvm->irq_lock); > } > > void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask) > @@ -234,6 +252,8 @@ void kvm_fire_mask_notifiers(struct kvm > struct kvm_irq_mask_notifier *kimn; > struct hlist_node *n; > > + WARN_ON(!mutex_is_locked(&kvm->lock)); > + > hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link) > if (kimn->irq == irq) > kimn->func(kimn, mask); > @@ -249,7 +269,9 @@ static void __kvm_free_irq_routing(struc > > void kvm_free_irq_routing(struct kvm *kvm) > { > + mutex_lock(&kvm->irq_lock); > __kvm_free_irq_routing(&kvm->irq_routing); > + mutex_unlock(&kvm->irq_lock); > } > > static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e, > @@ -323,13 +345,13 @@ int kvm_set_irq_routing(struct kvm *kvm, > e = NULL; > } > > - mutex_lock(&kvm->lock); > + mutex_lock(&kvm->irq_lock); > list_splice(&kvm->irq_routing, &tmp); > INIT_LIST_HEAD(&kvm->irq_routing); > list_splice(&irq_list, &kvm->irq_routing); > INIT_LIST_HEAD(&irq_list); > list_splice(&tmp, &irq_list); > - mutex_unlock(&kvm->lock); > + mutex_unlock(&kvm->irq_lock); > > r = 0; > > Index: kvm/arch/x86/kvm/lapic.c > =================================================================== > --- kvm.orig/arch/x86/kvm/lapic.c > +++ kvm/arch/x86/kvm/lapic.c > @@ -425,7 +425,9 @@ static void apic_set_eoi(struct kvm_lapi > trigger_mode = IOAPIC_LEVEL_TRIG; > else > trigger_mode = IOAPIC_EDGE_TRIG; > + mutex_lock(&apic->vcpu->kvm->irq_lock); > kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode); > + mutex_unlock(&apic->vcpu->kvm->irq_lock); > } > > static void apic_send_ipi(struct kvm_lapic *apic) > @@ -449,7 +451,9 @@ static void apic_send_ipi(struct kvm_lap > irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode, > irq.vector); > > + mutex_lock(&apic->vcpu->kvm->irq_lock); > kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq); > + mutex_unlock(&apic->vcpu->kvm->irq_lock); > } > > static u32 apic_get_tmcct(struct kvm_lapic *apic) > Index: kvm/include/linux/kvm_host.h > =================================================================== > --- kvm.orig/include/linux/kvm_host.h > +++ kvm/include/linux/kvm_host.h > @@ -375,7 +375,8 @@ int kvm_set_irq(struct kvm *kvm, int irq > void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin); > void kvm_register_irq_ack_notifier(struct kvm *kvm, > struct kvm_irq_ack_notifier *kian); > -void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian); > +void kvm_unregister_irq_ack_notifier(struct kvm *kvm, > + struct kvm_irq_ack_notifier *kian); > int kvm_request_irq_source_id(struct kvm *kvm); > void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id); > > >
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