[PATCH 1/5] KVM: Extract the irqfd_wakeup_pollin/irqfd_wakeup_pollup

Yunhong Jiang
2015-12-03T18:38:57Z

Separate the irqfd_wakeup_pollin/irqfd_wakeup_pollup from the
irqfd_wakeup, so that we can reuse the logic for MSI fastpath injection.

Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
---
virt/kvm/eventfd.c | 86 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 51 insertions(+), 35 deletions(-)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 46dbc0a7dfc1..c31d43b762db 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -180,6 +180,53 @@ int __attribute__((weak)) kvm_arch_set_irq_inatomic(
return -EWOULDBLOCK;
}

+static int
+irqfd_wakeup_pollin(struct kvm_kernel_irqfd *irqfd)
+{
+ struct kvm *kvm = irqfd->kvm;
+ struct kvm_kernel_irq_routing_entry irq;
+ unsigned seq;
+ int idx, ret;
+
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ do {
+ seq = read_seqcount_begin(&irqfd->irq_entry_sc);
+ irq = irqfd->irq_entry;
+ } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
+ /* An event has been signaled, inject an interrupt */
+ ret = kvm_arch_set_irq_inatomic(&irq, kvm,
+ KVM_USERSPACE_IRQ_SOURCE_ID, 1,
+ false);
+ srcu_read_unlock(&kvm->irq_srcu, idx);
+
+ return ret;
+}
+
+static int
+irqfd_wakeup_pollup(struct kvm_kernel_irqfd *irqfd)
+{
+ struct kvm *kvm = irqfd->kvm;
+ unsigned long flags;
+
+ spin_lock_irqsave(&kvm->irqfds.lock, flags);
+
+ /*
+ * We must check if someone deactivated the irqfd before
+ * we could acquire the irqfds.lock since the item is
+ * deactivated from the KVM side before it is unhooked from
+ * the wait-queue. If it is already deactivated, we can
+ * simply return knowing the other side will cleanup for us.
+ * We cannot race against the irqfd going away since the
+ * other side is required to acquire wqh->lock, which we hold
+ */
+ if (irqfd_is_active(irqfd))
+ irqfd_deactivate(irqfd);
+
+ spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
+
+ return 0;
+}
+
/*
* Called with wqh->lock held and interrupts disabled
*/
@@ -189,45 +236,14 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
struct kvm_kernel_irqfd *irqfd =
container_of(wait, struct kvm_kernel_irqfd, wait);
unsigned long flags = (unsigned long)key;
- struct kvm_kernel_irq_routing_entry irq;
- struct kvm *kvm = irqfd->kvm;
- unsigned seq;
- int idx;

- if (flags & POLLIN) {
- idx = srcu_read_lock(&kvm->irq_srcu);
- do {
- seq = read_seqcount_begin(&irqfd->irq_entry_sc);
- irq = irqfd->irq_entry;
- } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
- /* An event has been signaled, inject an interrupt */
- if (kvm_arch_set_irq_inatomic(&irq, kvm,
- KVM_USERSPACE_IRQ_SOURCE_ID, 1,
- false) == -EWOULDBLOCK)
+ if (flags & POLLIN)
+ if (irqfd_wakeup_pollin(irqfd) == -EWOULDBLOCK)
schedule_work(&irqfd->inject);
- srcu_read_unlock(&kvm->irq_srcu, idx);
- }

- if (flags & POLLHUP) {
+ if (flags & POLLHUP)
/* The eventfd is closing, detach from KVM */
- unsigned long flags;
-
- spin_lock_irqsave(&kvm->irqfds.lock, flags);
-
- /*
- * We must check if someone deactivated the irqfd before
- * we could acquire the irqfds.lock since the item is
- * deactivated from the KVM side before it is unhooked from
- * the wait-queue. If it is already deactivated, we can
- * simply return knowing the other side will cleanup for us.
- * We cannot race against the irqfd going away since the
- * other side is required to acquire wqh->lock, which we hold
- */
- if (irqfd_is_active(irqfd))
- irqfd_deactivate(irqfd);
-
- spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
- }
+ irqfd_wakeup_pollup(irqfd);

return 0;
}
--
1.8.3.1