From mboxrd@z Thu Jan 1 00:00:00 1970 From: jglauber@cavium.com (Jan Glauber) Date: Thu, 17 Aug 2017 10:14:23 +0200 Subject: [PATCH v2 3/3] vfio/pci: Don't probe devices that can't be reset In-Reply-To: <1502957663-5527-1-git-send-email-jglauber@cavium.com> References: <1502957663-5527-1-git-send-email-jglauber@cavium.com> Message-ID: <1502957663-5527-4-git-send-email-jglauber@cavium.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. 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 --- 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; -- 2.9.0.rc0.21.g7777322