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

[Brett Creeley <bcreeley@amd.com>]

On 6/14/2023 2:31 PM, Alex Williamson wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> 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?

Yeah I think it does make more sense to align. Thanks.

> 
>> +
>> +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.

Good suggestion. Once this series is merged we will submit the follow up 
patch. Thanks.

> 
>> +
>> +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

No good reason, so another good suggestion. I will fix this as well. 
Thanks again for the feedback.

> 
>> +
>> +     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_ */
>