[PATCH kvmtool v1 1/2] vfio-pci: Release INTx's guest to host eventfd properly

[Leo Yan <leo.yan@linaro.org>]

The PCI device INTx uses event fd 'unmask_fd' to signal the deassertion
of the line from guest to host; but this eventfd isn't released properly
when disable INTx.

When disable INTx this patch firstly unbinds interrupt signal by calling
ioctl VFIO_DEVICE_SET_IRQS and then it uses the new added field
'unmask_fd' in struct vfio_pci_device to close event fd.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 include/kvm/vfio.h |  1 +
 vfio/pci.c         | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/include/kvm/vfio.h b/include/kvm/vfio.h
index 60e6c54..28223cf 100644
--- a/include/kvm/vfio.h
+++ b/include/kvm/vfio.h
@@ -74,6 +74,7 @@ struct vfio_pci_device {
 
 	unsigned long			irq_modes;
 	int				intx_fd;
+	int				unmask_fd;
 	unsigned int			intx_gsi;
 	struct vfio_pci_msi_common	msi;
 	struct vfio_pci_msi_common	msix;
diff --git a/vfio/pci.c b/vfio/pci.c
index 03de3c1..c0683f6 100644
--- a/vfio/pci.c
+++ b/vfio/pci.c
@@ -996,18 +996,26 @@ static void vfio_pci_disable_intx(struct kvm *kvm, struct vfio_device *vdev)
 {
 	struct vfio_pci_device *pdev = &vdev->pci;
 	int gsi = pdev->intx_gsi;
-	struct vfio_irq_set irq_set = {
-		.argsz	= sizeof(irq_set),
+	struct vfio_irq_set trigger_irq = {
+		.argsz	= sizeof(trigger_irq),
 		.flags	= VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
 		.index	= VFIO_PCI_INTX_IRQ_INDEX,
 	};
 
+	struct vfio_irq_set unmask_irq = {
+		.argsz	= sizeof(unmask_irq),
+		.flags	= VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK,
+		.index	= VFIO_PCI_INTX_IRQ_INDEX,
+	};
+
 	pr_debug("user requested MSI, disabling INTx %d", gsi);
 
-	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
+	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger_irq);
+	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &unmask_irq);
 	irq__del_irqfd(kvm, gsi, pdev->intx_fd);
 
 	close(pdev->intx_fd);
+	close(pdev->unmask_fd);
 }
 
 static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev)
@@ -1095,6 +1103,7 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev)
 	}
 
 	pdev->intx_fd = trigger_fd;
+	pdev->unmask_fd = unmask_fd;
 	/* Guest is going to ovewrite our irq_line... */
 	pdev->intx_gsi = gsi;
 
-- 
2.19.1