KVM: ignore msi request if !level

Irqfd sets level for interrupt to 1 and then to 0.
For MSI, check level so that a single message is sent.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 56e696104d43..a9d7fd1f1d6a 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -139,7 +139,9 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
                 else
                         clear_bit(irq_source_id, irq_state);
                 sig_level = !!(*irq_state);
-        } else /* Deal with MSI/MSI-X */
+        } else if (!level)
+                return ret;
+        else /* Deal with MSI/MSI-X */
                 sig_level = 1;
 
         /* Not possible to detect if the guest uses the PIC or the