[PATCH v4 5/5] 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>
Signed-off-by: Feng Wu <feng.wu@intel.com>

---

v2 -> v3 (Feng Wu):
- Use kvm_arch_irq_bypass_start
- Remove kvm_arch_irq_bypass_update
- Add member 'struct irq_bypass_producer *producer' in
  'struct kvm_kernel_irqfd', it is needed by posted interrupt.
- Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign()

v1 -> v2:
- populate of kvm and gsi removed
- unregister the consumer on irqfd_shutdown
---
 include/linux/kvm_irqfd.h |  2 ++
 virt/kvm/eventfd.c        | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
index f926b39..0c1de05 100644
--- a/include/linux/kvm_irqfd.h
+++ b/include/linux/kvm_irqfd.h
@@ -64,6 +64,8 @@ struct kvm_kernel_irqfd {
 	struct list_head list;
 	poll_table pt;
 	struct work_struct shutdown;
+	struct irq_bypass_consumer consumer;
+	struct irq_bypass_producer *producer;
 };
 
 #endif /* __LINUX_KVM_IRQFD_H */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 647ffb8..08855de 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);
 }
@@ -380,6 +382,14 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	 */
 	fdput(f);
 
+	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.start = kvm_arch_irq_bypass_start;
+	ret = irq_bypass_register_consumer(&irqfd->consumer);
+	WARN_ON(ret);
+
 	return 0;
 
 fail:
-- 
1.9.1