[Qemu-devel] [PATCH] vfio-pci: Release all MSI-X vectors when disabled

[Qemu-devel] [PATCH] vfio-pci: Release all MSI-X vectors when disabled

[Alex Williamson]

We were relying on msix_unset_vector_notifiers() to release all the
vectors when we disable MSI-X, but this only happens when MSI-X is
still enabled on the device.  Perform further cleanup by releasing
any remaining vectors listed as in-use after this call.  This caused
a leak of IRQ routes on hotplug depending on how the guest OS prepared
the device for removal.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-stable@nongnu.org
---
 hw/misc/vfio.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index f7f8a19..355b018 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -878,8 +878,20 @@ static void vfio_disable_msi_common(VFIODevice *vdev)
 
 static void vfio_disable_msix(VFIODevice *vdev)
 {
+    int i;
+
     msix_unset_vector_notifiers(&vdev->pdev);
 
+    /*
+     * MSI-X will only release vectors if MSI-X is still enabled on the
+     * device, check through the rest and release it ourselves if necessary.
+     */
+    for (i = 0; i < vdev->nr_vectors; i++) {
+        if (vdev->msi_vectors[i].use) {
+            vfio_msix_vector_release(&vdev->pdev, i);
+        }
+    }
+
     if (vdev->nr_vectors) {
         vfio_disable_irqindex(vdev, VFIO_PCI_MSIX_IRQ_INDEX);
     }

Re: [Qemu-devel] [PATCH] vfio-pci: Release all MSI-X vectors when disabled

[Bandan Das]

Alex Williamson <alex.williamson@redhat.com> writes:

> We were relying on msix_unset_vector_notifiers() to release all the
> vectors when we disable MSI-X, but this only happens when MSI-X is
> still enabled on the device.  Perform further cleanup by releasing
> any remaining vectors listed as in-use after this call.  This caused
> a leak of IRQ routes on hotplug depending on how the guest OS prepared
> the device for removal.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> Cc: qemu-stable@nongnu.org
> ---
>  hw/misc/vfio.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index f7f8a19..355b018 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -878,8 +878,20 @@ static void vfio_disable_msi_common(VFIODevice *vdev)
>  
>  static void vfio_disable_msix(VFIODevice *vdev)
>  {
> +    int i;
> +
>      msix_unset_vector_notifiers(&vdev->pdev);
>  
> +    /*
> +     * MSI-X will only release vectors if MSI-X is still enabled on the
> +     * device, check through the rest and release it ourselves if necessary.
> +     */
> +    for (i = 0; i < vdev->nr_vectors; i++) {
> +        if (vdev->msi_vectors[i].use) {
> +            vfio_msix_vector_release(&vdev->pdev, i);
> +        }
> +    }
> +
>      if (vdev->nr_vectors) {
>          vfio_disable_irqindex(vdev, VFIO_PCI_MSIX_IRQ_INDEX);
>      }

Reviewed-by: Bandan Das <bsd@redhat.com>