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authorAlex Williamson <alex.williamson@redhat.com>2012-09-21 11:58:03 -0600
committerAvi Kivity <avi@redhat.com>2012-09-23 13:50:15 +0200
commit7a84428af7ca6a847f058c9ff244a18a2664fd1b (patch)
treee6c573c701736a75d618b670d66e98398b62769f /virt/kvm/irq_comm.c
parent1e08ec4a130e2745d96df169e67c58df98a07311 (diff)
KVM: Add resampling irqfds for level triggered interrupts
To emulate level triggered interrupts, add a resample option to KVM_IRQFD. When specified, a new resamplefd is provided that notifies the user when the irqchip has been resampled by the VM. This may, for instance, indicate an EOI. Also in this mode, posting of an interrupt through an irqfd only asserts the interrupt. On resampling, the interrupt is automatically de-asserted prior to user notification. This enables level triggered interrupts to be posted and re-enabled from vfio with no userspace intervention. All resampling irqfds can make use of a single irq source ID, so we reserve a new one for this interface. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/irq_comm.c')
-rw-r--r--virt/kvm/irq_comm.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 3ca89c451d6..2eb58af7ee9 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -228,6 +228,9 @@ int kvm_request_irq_source_id(struct kvm *kvm)
}
ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
+#ifdef CONFIG_X86
+ ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
+#endif
set_bit(irq_source_id, bitmap);
unlock:
mutex_unlock(&kvm->irq_lock);
@@ -238,6 +241,9 @@ unlock:
void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
{
ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
+#ifdef CONFIG_X86
+ ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
+#endif
mutex_lock(&kvm->irq_lock);
if (irq_source_id < 0 ||