Messages in this thread | | | Date | Thu, 17 Aug 2017 07:00:17 -0600 | From | Alex Williamson <> | Subject | Re: [PATCH v2 3/3] vfio/pci: Don't probe devices that can't be reset |
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On Thu, 17 Aug 2017 10:14:23 +0200 Jan Glauber <jglauber@cavium.com> wrote:
> If a PCI device supports neither function-level reset, nor slot > or bus reset then refuse to probe it. A line is printed to inform > the user.
But that's not what this does, this requires that the device is on a reset-able bus. This is a massive regression. With this we could no longer assign devices on the root complex or any device which doesn't return from bus reset and currently makes use of the NO_BUS_RESET flag and works happily otherwise. Full NAK. Thanks,
Alex
> Without this change starting qemu with a vfio-pci device can lead to > a kernel panic on some Cavium cn8xxx systems, depending on the used > device. > > Signed-off-by: Jan Glauber <jglauber@cavium.com> > --- > drivers/vfio/pci/vfio_pci.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > index 063c1ce..029ba13 100644 > --- a/drivers/vfio/pci/vfio_pci.c > +++ b/drivers/vfio/pci/vfio_pci.c > @@ -1196,6 +1196,12 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL) > return -EINVAL; > > + ret = pci_probe_reset_bus(pdev->bus); > + if (ret) { > + dev_warn(&pdev->dev, "Refusing to probe because reset is not possible.\n"); > + return ret; > + } > + > group = vfio_iommu_group_get(&pdev->dev); > if (!group) > return -EINVAL;
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