Re: [PATCH v10 vfio 2/7] vfio/pds: Initial support for pds_vfio VFIO driver

[Alex Williamson <alex.williamson@redhat.com>]

On Fri, 2 Jun 2023 15:03:13 -0700
Brett Creeley <brett.creeley@amd.com> wrote:

> This is the initial framework for the new pds_vfio device driver. This
> does the very basics of registering the PDS PCI device and configuring
> it as a VFIO PCI device.
> 
> With this change, the VF device can be bound to the pds_vfio driver on
> the host and presented to the VM as the VF's device type.
> 
> Signed-off-by: Brett Creeley <brett.creeley@amd.com>
> Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
> ---
>  drivers/vfio/pci/Makefile       |  2 +
>  drivers/vfio/pci/pds/Makefile   |  8 ++++
>  drivers/vfio/pci/pds/pci_drv.c  | 69 +++++++++++++++++++++++++++++++
>  drivers/vfio/pci/pds/vfio_dev.c | 72 +++++++++++++++++++++++++++++++++
>  drivers/vfio/pci/pds/vfio_dev.h | 20 +++++++++
>  5 files changed, 171 insertions(+)
>  create mode 100644 drivers/vfio/pci/pds/Makefile
>  create mode 100644 drivers/vfio/pci/pds/pci_drv.c
>  create mode 100644 drivers/vfio/pci/pds/vfio_dev.c
>  create mode 100644 drivers/vfio/pci/pds/vfio_dev.h
> 
> diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
> index 24c524224da5..45167be462d8 100644
> --- a/drivers/vfio/pci/Makefile
> +++ b/drivers/vfio/pci/Makefile
> @@ -11,3 +11,5 @@ obj-$(CONFIG_VFIO_PCI) += vfio-pci.o
>  obj-$(CONFIG_MLX5_VFIO_PCI)           += mlx5/
>  
>  obj-$(CONFIG_HISI_ACC_VFIO_PCI) += hisilicon/
> +
> +obj-$(CONFIG_PDS_VFIO_PCI) += pds/
> diff --git a/drivers/vfio/pci/pds/Makefile b/drivers/vfio/pci/pds/Makefile
> new file mode 100644
> index 000000000000..e1a55ae0f079
> --- /dev/null
> +++ b/drivers/vfio/pci/pds/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2023 Advanced Micro Devices, Inc.
> +
> +obj-$(CONFIG_PDS_VFIO_PCI) += pds_vfio.o

Given the existing drivers:

obj-$(CONFIG_MLX5_VFIO_PCI) += mlx5-vfio-pci.o
obj-$(CONFIG_HISI_ACC_VFIO_PCI) += hisi-acc-vfio-pci.o

Does it make sense to name this one pds-vfio-pci?

> +
> +pds_vfio-y := \
> +	pci_drv.o	\
> +	vfio_dev.o
> diff --git a/drivers/vfio/pci/pds/pci_drv.c b/drivers/vfio/pci/pds/pci_drv.c
> new file mode 100644
> index 000000000000..0e84249069d4
> --- /dev/null
> +++ b/drivers/vfio/pci/pds/pci_drv.c
> @@ -0,0 +1,69 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/types.h>
> +#include <linux/vfio.h>
> +
> +#include <linux/pds/pds_core_if.h>
> +
> +#include "vfio_dev.h"
> +
> +#define PDS_VFIO_DRV_DESCRIPTION	"AMD/Pensando VFIO Device Driver"
> +#define PCI_VENDOR_ID_PENSANDO		0x1dd8

Isn't this a duplicate from the above include:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/pds/pds_core_if.h#n7

I also find it defined in ionic.h, which means that it now satisfies
pci_ids.h requirement that the identifier is shared between multiple
drivers.  A trivial follow-up after this series might combine them
there.

> +
> +static int pds_vfio_pci_probe(struct pci_dev *pdev,
> +			      const struct pci_device_id *id)
> +{
> +	struct pds_vfio_pci_device *pds_vfio;
> +	int err;
> +
> +	pds_vfio = vfio_alloc_device(pds_vfio_pci_device, vfio_coredev.vdev,
> +				     &pdev->dev, pds_vfio_ops_info());
> +	if (IS_ERR(pds_vfio))
> +		return PTR_ERR(pds_vfio);
> +
> +	dev_set_drvdata(&pdev->dev, &pds_vfio->vfio_coredev);
> +
> +	err = vfio_pci_core_register_device(&pds_vfio->vfio_coredev);
> +	if (err)
> +		goto out_put_vdev;
> +
> +	return 0;
> +
> +out_put_vdev:
> +	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
> +	return err;
> +}
> +
> +static void pds_vfio_pci_remove(struct pci_dev *pdev)
> +{
> +	struct pds_vfio_pci_device *pds_vfio = pds_vfio_pci_drvdata(pdev);
> +
> +	vfio_pci_core_unregister_device(&pds_vfio->vfio_coredev);
> +	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
> +}
> +
> +static const struct pci_device_id
> +pds_vfio_pci_table[] = {
> +	{ PCI_DRIVER_OVERRIDE_DEVICE_VFIO(PCI_VENDOR_ID_PENSANDO, 0x1003) }, /* Ethernet VF */
> +	{ 0, }
> +};
> +MODULE_DEVICE_TABLE(pci, pds_vfio_pci_table);
> +
> +static struct pci_driver pds_vfio_pci_driver = {
> +	.name = KBUILD_MODNAME,
> +	.id_table = pds_vfio_pci_table,
> +	.probe = pds_vfio_pci_probe,
> +	.remove = pds_vfio_pci_remove,
> +	.driver_managed_dma = true,
> +};
> +
> +module_pci_driver(pds_vfio_pci_driver);
> +
> +MODULE_DESCRIPTION(PDS_VFIO_DRV_DESCRIPTION);
> +MODULE_AUTHOR("Advanced Micro Devices, Inc.");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c
> new file mode 100644
> index 000000000000..4038dac90a97
> --- /dev/null
> +++ b/drivers/vfio/pci/pds/vfio_dev.c
> @@ -0,0 +1,72 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
> +
> +#include <linux/vfio.h>
> +#include <linux/vfio_pci_core.h>
> +
> +#include "vfio_dev.h"
> +
> +struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_core_device *core_device = dev_get_drvdata(&pdev->dev);
> +
> +	return container_of(core_device, struct pds_vfio_pci_device,
> +			    vfio_coredev);
> +}
> +
> +static int pds_vfio_init_device(struct vfio_device *vdev)
> +{
> +	struct pds_vfio_pci_device *pds_vfio =
> +		container_of(vdev, struct pds_vfio_pci_device,
> +			     vfio_coredev.vdev);
> +	struct pci_dev *pdev = to_pci_dev(vdev->dev);
> +	int err;
> +
> +	err = vfio_pci_core_init_dev(vdev);
> +	if (err)
> +		return err;
> +
> +	pds_vfio->vf_id = pci_iov_vf_id(pdev);
> +	pds_vfio->pci_id = PCI_DEVID(pdev->bus->number, pdev->devfn);

We only ever end up using pci_id for a debug print here that could use
a local variable and a slow path client registration that has access to
pdev to do a lookup on demand.  Why do we bother caching it on the
pds_vfio_pci_device?  Thanks,

Alex

> +
> +	return 0;
> +}
> +
> +static int pds_vfio_open_device(struct vfio_device *vdev)
> +{
> +	struct pds_vfio_pci_device *pds_vfio =
> +		container_of(vdev, struct pds_vfio_pci_device,
> +			     vfio_coredev.vdev);
> +	int err;
> +
> +	err = vfio_pci_core_enable(&pds_vfio->vfio_coredev);
> +	if (err)
> +		return err;
> +
> +	vfio_pci_core_finish_enable(&pds_vfio->vfio_coredev);
> +
> +	return 0;
> +}
> +
> +static const struct vfio_device_ops pds_vfio_ops = {
> +	.name = "pds-vfio",
> +	.init = pds_vfio_init_device,
> +	.release = vfio_pci_core_release_dev,
> +	.open_device = pds_vfio_open_device,
> +	.close_device = vfio_pci_core_close_device,
> +	.ioctl = vfio_pci_core_ioctl,
> +	.device_feature = vfio_pci_core_ioctl_feature,
> +	.read = vfio_pci_core_read,
> +	.write = vfio_pci_core_write,
> +	.mmap = vfio_pci_core_mmap,
> +	.request = vfio_pci_core_request,
> +	.match = vfio_pci_core_match,
> +	.bind_iommufd = vfio_iommufd_physical_bind,
> +	.unbind_iommufd = vfio_iommufd_physical_unbind,
> +	.attach_ioas = vfio_iommufd_physical_attach_ioas,
> +};
> +
> +const struct vfio_device_ops *pds_vfio_ops_info(void)
> +{
> +	return &pds_vfio_ops;
> +}
> diff --git a/drivers/vfio/pci/pds/vfio_dev.h b/drivers/vfio/pci/pds/vfio_dev.h
> new file mode 100644
> index 000000000000..66cfcab5b5bf
> --- /dev/null
> +++ b/drivers/vfio/pci/pds/vfio_dev.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
> +
> +#ifndef _VFIO_DEV_H_
> +#define _VFIO_DEV_H_
> +
> +#include <linux/pci.h>
> +#include <linux/vfio_pci_core.h>
> +
> +struct pds_vfio_pci_device {
> +	struct vfio_pci_core_device vfio_coredev;
> +
> +	int vf_id;
> +	int pci_id;
> +};
> +
> +const struct vfio_device_ops *pds_vfio_ops_info(void);
> +struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev);
> +
> +#endif /* _VFIO_DEV_H_ */