linux-kernel - [PATCH] vfio-pci: Disable INTx after MSI/X teardown

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Date:   Thu, 22 Sep 2016 11:28:29 -0600
From:   Alex Williamson <alex.williamson@...hat.com>
To:     kvm@...r.kernel.org
Cc:     alex.williamson@...hat.com, linux-kernel@...r.kernel.org
Subject: [PATCH] vfio-pci: Disable INTx after MSI/X teardown

The MSI/X shutdown path can gratuitously enable INTx, which is not
something we want to happen if we're dealing with broken INTx device.

Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
---
 drivers/vfio/pci/vfio_pci_intrs.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 152b438..aa23e9a 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -414,6 +414,13 @@ static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix)
 	} else
 		pci_disable_msi(pdev);
 
+	/*
+	 * Both disable paths above use pci_intx_for_msi() to clear DisINTx
+	 * via their shutdown paths.  Restore for NoINTx devices.
+	 */
+	if (vdev->nointx)
+		pci_intx(pdev, 0);
+
 	vdev->irq_type = VFIO_PCI_NUM_IRQS;
 	vdev->num_ctx = 0;
 	kfree(vdev->ctx);