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Subject: Re: [pci PATCH v8 4/4] pci-pf-stub: Add PF driver stub for PFs that
 function only to enable VFs
To:     Alexander Duyck <alexander.h.duyck@intel.com>, bhelgaas@google.com,
        linux-pci@vger.kernel.org
Cc:     virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org,
        netdev@vger.kernel.org, dan.daly@intel.com,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        keith.busch@intel.com, netanel@amazon.com, ddutile@redhat.com,
        mheyne@amazon.de, liang-min.wang@intel.com,
        mark.d.rustad@intel.com, dwmw2@infradead.org, hch@lst.de,
        dwmw@amazon.co.uk
References: <20180420162633.46077.49012.stgit@ahduyck-green-test.jf.intel.com>
 <20180420163109.46077.60334.stgit@ahduyck-green-test.jf.intel.com>
From:   Gregory Rose <gvrose8192@gmail.com>
Message-ID: <33785f68-d445-f49b-5668-3195cfa32159@gmail.com>
Date:   Fri, 20 Apr 2018 15:08:46 -0700
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On 4/20/2018 9:31 AM, Alexander Duyck wrote:
> Add a new driver called "pci-pf-stub" to act as a "white-list" for PF
> devices that provide no other functionality other then acting as a means of
> allocating a set of VFs. For now I only have one example ID provided by
> Amazon in terms of devices that require this functionality. The general
> idea is that in the future we will see other devices added as vendors come
> up with devices where the PF is more or less just a lightweight shim used
> to allocate VFs.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
>
> v6: New driver to address concerns about Amazon devices left unsupported
> v7: Dropped pci_id table explanation from pci-pf-stub driver
>
>   drivers/pci/Kconfig       |   12 ++++++++++
>   drivers/pci/Makefile      |    2 ++
>   drivers/pci/pci-pf-stub.c |   54 +++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/pci_ids.h   |    2 ++
>   4 files changed, 70 insertions(+)
>   create mode 100644 drivers/pci/pci-pf-stub.c
>
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 34b56a8..cdef2a2 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -71,6 +71,18 @@ config PCI_STUB
>   
>   	  When in doubt, say N.
>   
> +config PCI_PF_STUB
> +	tristate "PCI PF Stub driver"
> +	depends on PCI
> +	depends on PCI_IOV
> +	help
> +	  Say Y or M here if you want to enable support for devices that
> +	  require SR-IOV support, while at the same time the PF itself is
> +	  not providing any actual services on the host itself such as
> +	  storage or networking.
> +
> +	  When in doubt, say N.
> +
>   config XEN_PCIDEV_FRONTEND
>           tristate "Xen PCI Frontend"
>           depends on PCI && X86 && XEN
> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> index 9419709..4e133d3 100644
> --- a/drivers/pci/Makefile
> +++ b/drivers/pci/Makefile
> @@ -43,6 +43,8 @@ obj-$(CONFIG_PCI_SYSCALL) += syscall.o
>   
>   obj-$(CONFIG_PCI_STUB) += pci-stub.o
>   
> +obj-$(CONFIG_PCI_PF_STUB) += pci-pf-stub.o
> +
>   obj-$(CONFIG_PCI_ECAM) += ecam.o
>   
>   obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
> diff --git a/drivers/pci/pci-pf-stub.c b/drivers/pci/pci-pf-stub.c
> new file mode 100644
> index 0000000..9d5fdf2
> --- /dev/null
> +++ b/drivers/pci/pci-pf-stub.c
> @@ -0,0 +1,54 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* pci-pf-stub - simple stub driver for PCI SR-IOV PF device
> + *
> + * This driver is meant to act as a "white-list" for devices that provde
> + * SR-IOV functionality while at the same time not actually needing a
> + * driver of their own.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +
> +/**
> + * pci_pf_stub_white_list - White list of devices to bind pci-pf-stub onto
> + *
> + * This table provides the list of IDs this driver is supposed to bind
> + * onto. You could think of this as a list of "quirked" devices where we
> + * are adding support for SR-IOV here since there are no other drivers
> + * that they would be running under.
> + */
> +static const struct pci_device_id pci_pf_stub_white_list[] = {
> +	{ PCI_VDEVICE(AMAZON, 0x0053) },
> +	/* required last entry */
> +	{ 0 }
> +};
> +MODULE_DEVICE_TABLE(pci, pci_pf_stub_white_list);
> +
> +static int pci_pf_stub_probe(struct pci_dev *dev,
> +			     const struct pci_device_id *id)
> +{
> +	pci_info(dev, "claimed by pci-pf-stub\n");
> +	return 0;
> +}
> +
> +static struct pci_driver pf_stub_driver = {
> +	.name			= "pci-pf-stub",
> +	.id_table		= pci_pf_stub_white_list,
> +	.probe			= pci_pf_stub_probe,
> +	.sriov_configure	= pci_sriov_configure_simple,
> +};
> +
> +static int __init pci_pf_stub_init(void)
> +{
> +	return pci_register_driver(&pf_stub_driver);
> +}
> +
> +static void __exit pci_pf_stub_exit(void)
> +{
> +	pci_unregister_driver(&pf_stub_driver);
> +}
> +
> +module_init(pci_pf_stub_init);
> +module_exit(pci_pf_stub_exit);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> index a637a7d..62dab14 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -2549,6 +2549,8 @@
>   #define PCI_VENDOR_ID_CIRCUITCO		0x1cc8
>   #define PCI_SUBSYSTEM_ID_CIRCUITCO_MINNOWBOARD	0x0001
>   
> +#define PCI_VENDOR_ID_AMAZON		0x1d0f
> +
>   #define PCI_VENDOR_ID_TEKRAM		0x1de1
>   #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29
>   
>

LGTM

Reviewed-by: Greg Rose <gvrose8192@gmail.com>