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-rw-r--r--virt/kvm/eventfd.c91
1 files changed, 79 insertions, 12 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index c1f1e3c..2ca4535 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -44,14 +44,19 @@
*/
struct _irqfd {
- struct kvm *kvm;
- struct eventfd_ctx *eventfd;
- int gsi;
- struct list_head list;
- poll_table pt;
- wait_queue_t wait;
- struct work_struct inject;
- struct work_struct shutdown;
+ /* Used for MSI fast-path */
+ struct kvm *kvm;
+ wait_queue_t wait;
+ /* Update side is protected by irqfds.lock */
+ struct kvm_kernel_irq_routing_entry __rcu *irq_entry;
+ /* Used for level IRQ fast-path */
+ int gsi;
+ struct work_struct inject;
+ /* Used for setup/shutdown */
+ struct eventfd_ctx *eventfd;
+ struct list_head list;
+ poll_table pt;
+ struct work_struct shutdown;
};
static struct workqueue_struct *irqfd_cleanup_wq;
@@ -125,14 +130,22 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
{
struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
unsigned long flags = (unsigned long)key;
+ struct kvm_kernel_irq_routing_entry *irq;
+ struct kvm *kvm = irqfd->kvm;
- if (flags & POLLIN)
+ if (flags & POLLIN) {
+ rcu_read_lock();
+ irq = rcu_dereference(irqfd->irq_entry);
/* An event has been signaled, inject an interrupt */
- schedule_work(&irqfd->inject);
+ if (irq)
+ kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
+ else
+ schedule_work(&irqfd->inject);
+ rcu_read_unlock();
+ }
if (flags & POLLHUP) {
/* The eventfd is closing, detach from KVM */
- struct kvm *kvm = irqfd->kvm;
unsigned long flags;
spin_lock_irqsave(&kvm->irqfds.lock, flags);
@@ -163,9 +176,31 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
add_wait_queue(wqh, &irqfd->wait);
}
+/* Must be called under irqfds.lock */
+static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd,
+ struct kvm_irq_routing_table *irq_rt)
+{
+ struct kvm_kernel_irq_routing_entry *e;
+ struct hlist_node *n;
+
+ if (irqfd->gsi >= irq_rt->nr_rt_entries) {
+ rcu_assign_pointer(irqfd->irq_entry, NULL);
+ return;
+ }
+
+ hlist_for_each_entry(e, n, &irq_rt->map[irqfd->gsi], link) {
+ /* Only fast-path MSI. */
+ if (e->type == KVM_IRQ_ROUTING_MSI)
+ rcu_assign_pointer(irqfd->irq_entry, e);
+ else
+ rcu_assign_pointer(irqfd->irq_entry, NULL);
+ }
+}
+
static int
kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
{
+ struct kvm_irq_routing_table *irq_rt;
struct _irqfd *irqfd, *tmp;
struct file *file = NULL;
struct eventfd_ctx *eventfd = NULL;
@@ -215,6 +250,10 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
goto fail;
}
+ irq_rt = rcu_dereference_protected(kvm->irq_routing,
+ lockdep_is_held(&kvm->irqfds.lock));
+ irqfd_update(kvm, irqfd, irq_rt);
+
events = file->f_op->poll(file, &irqfd->pt);
list_add_tail(&irqfd->list, &kvm->irqfds.items);
@@ -271,8 +310,17 @@ kvm_irqfd_deassign(struct kvm *kvm, int fd, int gsi)
spin_lock_irq(&kvm->irqfds.lock);
list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
- if (irqfd->eventfd == eventfd && irqfd->gsi == gsi)
+ if (irqfd->eventfd == eventfd && irqfd->gsi == gsi) {
+ /*
+ * This rcu_assign_pointer is needed for when
+ * another thread calls kvm_irqfd_update before
+ * we flush workqueue below.
+ * It is paired with synchronize_rcu done by caller
+ * of that function.
+ */
+ rcu_assign_pointer(irqfd->irq_entry, NULL);
irqfd_deactivate(irqfd);
+ }
}
spin_unlock_irq(&kvm->irqfds.lock);
@@ -322,6 +370,25 @@ kvm_irqfd_release(struct kvm *kvm)
}
/*
+ * Change irq_routing and irqfd.
+ * Caller must invoke synchronize_rcu afterwards.
+ */
+void kvm_irq_routing_update(struct kvm *kvm,
+ struct kvm_irq_routing_table *irq_rt)
+{
+ struct _irqfd *irqfd;
+
+ spin_lock_irq(&kvm->irqfds.lock);
+
+ rcu_assign_pointer(kvm->irq_routing, irq_rt);
+
+ list_for_each_entry(irqfd, &kvm->irqfds.items, list)
+ irqfd_update(kvm, irqfd, irq_rt);
+
+ spin_unlock_irq(&kvm->irqfds.lock);
+}
+
+/*
* create a host-wide workqueue for issuing deferred shutdown requests
* aggregated from all vm* instances. We need our own isolated single-thread
* queue to prevent deadlock against flushing the normal work-queue.
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