[RFC v2 6/6] KVM: eventfd: add irq bypass consumer management

[Eric Auger <eric.auger@linaro.org>]

This patch adds the registration/unregistration of an
irq_bypass_consumer on irqfd assignment/deassignment.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---

v1 -> v2:
- populate of kvm and gsi removed
- unregister the consumer on irqfd_shutdown
---
 include/linux/kvm_irqfd.h |  1 +
 virt/kvm/eventfd.c        | 14 +++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
index f926b39..3c0bd07 100644
--- a/include/linux/kvm_irqfd.h
+++ b/include/linux/kvm_irqfd.h
@@ -64,6 +64,7 @@ struct kvm_kernel_irqfd {
 	struct list_head list;
 	poll_table pt;
 	struct work_struct shutdown;
+	struct irq_bypass_consumer consumer;
 };
 
 #endif /* __LINUX_KVM_IRQFD_H */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index b79dc61..9452754 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -35,6 +35,7 @@
 #include <linux/srcu.h>
 #include <linux/slab.h>
 #include <linux/seqlock.h>
+#include <linux/irqbypass.h>
 #include <trace/events/kvm.h>
 
 #include <kvm/iodev.h>
@@ -140,6 +141,7 @@ irqfd_shutdown(struct work_struct *work)
 	/*
 	 * It is now safe to release the object's resources
 	 */
+	irq_bypass_unregister_consumer(&irqfd->consumer);
 	eventfd_ctx_put(irqfd->eventfd);
 	kfree(irqfd);
 }
@@ -380,7 +382,14 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	 */
 	fdput(f);
 
-	/* irq_bypass_register_consumer(); */
+	irqfd->consumer.token = (void *)irqfd->eventfd;
+	irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
+	irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
+	irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
+	irqfd->consumer.resume = kvm_arch_irq_bypass_resume;
+	irqfd->consumer.update = kvm_arch_irq_bypass_update;
+	ret = irq_bypass_register_consumer(&irqfd->consumer);
+	WARN_ON(ret);
 
 	return 0;
 
@@ -481,8 +490,6 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
 	struct kvm_kernel_irqfd *irqfd, *tmp;
 	struct eventfd_ctx *eventfd;
 
-	/* irq_bypass_unregister_consumer() */
-
 	eventfd = eventfd_ctx_fdget(args->fd);
 	if (IS_ERR(eventfd))
 		return PTR_ERR(eventfd);
@@ -501,6 +508,7 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
 			irqfd->irq_entry.type = 0;
 			write_seqcount_end(&irqfd->irq_entry_sc);
 			irqfd_deactivate(irqfd);
+			irq_bypass_unregister_consumer(&irqfd->consumer);
 		}
 	}
 
-- 
1.9.1