Re: [RFC 5/5] vfio/qat: Add vfio_pci driver for Intel QAT VF devices

From: Brett Creeley <bcreeley@amd.com>
To: Xin Zeng <xin.zeng@intel.com>,
	linux-crypto@vger.kernel.org, kvm@vger.kernel.org
Cc: giovanni.cabiddu@intel.com, andriy.shevchenko@linux.intel.com,
	Yahui Cao <yahui.cao@intel.com>
Subject: Re: [RFC 5/5] vfio/qat: Add vfio_pci driver for Intel QAT VF devices
Date: Wed, 16 Aug 2023 09:20:07 -0700	[thread overview]
Message-ID: <10f3159d-62ae-0e4c-8ba4-6f7819a47ecb@amd.com> (raw)
In-Reply-To: <20230630131304.64243-6-xin.zeng@intel.com>

On 6/30/2023 6:13 AM, Xin Zeng wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> Add vfio pci driver for Intel QAT VF devices.
> 
> This driver uses vfio_pci_core to register to the VFIO subsystem. It
> acts as a vfio agent and interacts with the QAT PF driver to implement
> VF live migration.
> 
> Co-developed-by: Yahui Cao <yahui.cao@intel.com>
> Signed-off-by: Yahui Cao <yahui.cao@intel.com>
> Signed-off-by: Xin Zeng <xin.zeng@intel.com>
> ---
>   drivers/vfio/pci/Kconfig                 |   2 +
>   drivers/vfio/pci/Makefile                |   1 +
>   drivers/vfio/pci/qat/Kconfig             |  13 +
>   drivers/vfio/pci/qat/Makefile            |   4 +
>   drivers/vfio/pci/qat/qat_vfio_pci_main.c | 518 +++++++++++++++++++++++
>   5 files changed, 538 insertions(+)
>   create mode 100644 drivers/vfio/pci/qat/Kconfig
>   create mode 100644 drivers/vfio/pci/qat/Makefile
>   create mode 100644 drivers/vfio/pci/qat/qat_vfio_pci_main.c
> 

[...]

> +
> +static int
> +qat_vf_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct qat_vf_core_device *qat_vdev;
> +       int ret;
> +
> +       qat_vdev = vfio_alloc_device(qat_vf_core_device, core_device.vdev, dev, &qat_vf_pci_ops);
> +       if (IS_ERR(qat_vdev))
> +               return PTR_ERR(qat_vdev);
> +
> +       qat_vdev->vf_id = pci_iov_vf_id(pdev);
> +       qat_vdev->parent = pdev->physfn;
> +       if (!qat_vdev->parent || qat_vdev->vf_id < 0)
> +               return -EINVAL;

Since vfio_alloc_device() was successful you need to call 
vfio_put_device() in this error case as well.

> +
> +       pci_set_drvdata(pdev, &qat_vdev->core_device);
> +       ret = vfio_pci_core_register_device(&qat_vdev->core_device);
> +       if (ret)
> +               goto out_put_device;
> +
> +       return 0;
> +
> +out_put_device:
> +       vfio_put_device(&qat_vdev->core_device.vdev);
> +       return ret;
> +}
> +
> +static struct qat_vf_core_device *qat_vf_drvdata(struct pci_dev *pdev)
> +{
> +       struct vfio_pci_core_device *core_device = pci_get_drvdata(pdev);
> +
> +       return container_of(core_device, struct qat_vf_core_device, core_device);
> +}
> +
> +static void qat_vf_vfio_pci_remove(struct pci_dev *pdev)
> +{
> +       struct qat_vf_core_device *qat_vdev = qat_vf_drvdata(pdev);
> +
> +       vfio_pci_core_unregister_device(&qat_vdev->core_device);
> +       vfio_put_device(&qat_vdev->core_device.vdev);
> +}
> +
> +static const struct pci_device_id qat_vf_vfio_pci_table[] = {
> +       /* Intel QAT GEN4 4xxx VF device */
> +       { PCI_DRIVER_OVERRIDE_DEVICE_VFIO(PCI_VENDOR_ID_INTEL, 0x4941) },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(pci, qat_vf_vfio_pci_table);
> +
> +static struct pci_driver qat_vf_vfio_pci_driver = {
> +       .name = "qat_vfio_pci",
> +       .id_table = qat_vf_vfio_pci_table,
> +       .probe = qat_vf_vfio_pci_probe,
> +       .remove = qat_vf_vfio_pci_remove,
> +       .driver_managed_dma = true,
> +};
> +module_pci_driver(qat_vf_vfio_pci_driver)
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_DESCRIPTION("QAT VFIO PCI - VFIO PCI driver with live migration support for Intel(R) QAT device family");
> --
> 2.18.2
> 