Michael S. Tsirkin wrote: > Here's an untested patch with partial support for level triggered > interrupts in irqfd. What this patch has: support for clearing interrupt > on ack. What this patch does not have: support signalling eventfd on ack > so that userspace can take action and e.g. reenable interrupt. > > Gleb, Marcelo, I'd like your input on the approach taken wrt locking. > Does it look sane? > > Avi, how's the interface? I intend to also add an eventfd probably in > the padding in the irqfd struct. > > Signed-off-by: Michael S. Tsirkin <[email protected]>
Patch seems reasonable to me. Acked-by: Gregory Haskins <[email protected]> > > --- > > diff --git a/include/linux/kvm.h b/include/linux/kvm.h > index 230a91a..8bf16af 100644 > --- a/include/linux/kvm.h > +++ b/include/linux/kvm.h > @@ -488,6 +488,7 @@ struct kvm_x86_mce { > #endif > > #define KVM_IRQFD_FLAG_DEASSIGN (1 << 0) > +#define KVM_IRQFD_FLAG_LEVEL (1 << 1) > > struct kvm_irqfd { > __u32 fd; > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > index 99017e8..fcbf5b5 100644 > --- a/virt/kvm/eventfd.c > +++ b/virt/kvm/eventfd.c > @@ -45,12 +45,14 @@ struct _irqfd { > struct kvm *kvm; > struct eventfd_ctx *eventfd; > int gsi; > + int is_level; > struct list_head list; > poll_table pt; > wait_queue_head_t *wqh; > wait_queue_t wait; > struct work_struct inject; > struct work_struct shutdown; > + struct kvm_irq_ack_notifier kian; > }; > > static struct workqueue_struct *irqfd_cleanup_wq; > @@ -63,10 +65,15 @@ irqfd_inject(struct work_struct *work) > > mutex_lock(&kvm->irq_lock); > kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1); > - kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0); > + if (!irqfd->is_level) > + kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0); > mutex_unlock(&kvm->irq_lock); > } > > +static void irqfd_irq_acked(struct kvm_irq_ack_notifier *kian) > +{ > + kvm_set_irq(kian->kvm, KVM_USERSPACE_IRQ_SOURCE_ID, kian->gsi, 0); > +} > /* > * Race-free decouple logic (ordering is critical) > */ > @@ -87,6 +94,9 @@ irqfd_shutdown(struct work_struct *work) > */ > flush_work(&irqfd->inject); > > + if (irqfd->is_level) > + kvm_unregister_irq_ack_notifier(&irqfd->kian); > + > /* > * It is now safe to release the object's resources > */ > @@ -166,7 +176,7 @@ irqfd_ptable_queue_proc(struct file *file, > wait_queue_head_t *wqh, > } > > static int > -kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi) > +kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi, int is_level) > { > struct _irqfd *irqfd; > struct file *file = NULL; > @@ -180,6 +190,7 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi) > > irqfd->kvm = kvm; > irqfd->gsi = gsi; > + irqfd->is_level = is_level; > INIT_LIST_HEAD(&irqfd->list); > INIT_WORK(&irqfd->inject, irqfd_inject); > INIT_WORK(&irqfd->shutdown, irqfd_shutdown); > @@ -198,6 +209,12 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi) > > irqfd->eventfd = eventfd; > > + if (is_level) { > + irqfd->kian.gsi = gsi; > + irqfd->kian.irq_acked = irqfd_irq_acked; > + kvm_register_irq_ack_notifier(&irqfd->kian); > + } > + > /* > * Install our own custom wake-up handling so we are notified via > * a callback whenever someone signals the underlying eventfd > @@ -281,10 +298,13 @@ kvm_irqfd_deassign(struct kvm *kvm, int fd, int gsi) > int > kvm_irqfd(struct kvm *kvm, int fd, int gsi, int flags) > { > + if (flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_LEVEL)) > + return -EINVAL; > + > if (flags & KVM_IRQFD_FLAG_DEASSIGN) > return kvm_irqfd_deassign(kvm, fd, gsi); > > - return kvm_irqfd_assign(kvm, fd, gsi); > + return kvm_irqfd_assign(kvm, fd, gsi, !!(flags & KVM_IRQFD_FLAG_LEVEL)); > } > > /* > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html
signature.asc
Description: OpenPGP digital signature
