Commit a8ccf8a6 authored by Alexander Duyck's avatar Alexander Duyck Committed by Bjorn Helgaas
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PCI/IOV: Add pci-pf-stub driver for PFs that only enable VFs 



Some SR-IOV PF devices provide no functionality other than acting as a
means of enabling VFs.  For these devices, we want to enable the VFs and
assign them to guest virtual machines, but there's no need to have a driver
for the PF itself.

Add a new pci-pf-stub driver to claim those PF devices and provide the
generic VF enable functionality.  An administrator can use the sysfs
"sriov_numvfs" file to enable VFs, then assign them to guests.

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: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
[bhelgaas: changelog]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarGreg Rose <gvrose8192@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 8effc395

drivers/pci/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -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

drivers/pci/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ obj-$(CONFIG_PCI_LABEL) += pci-label.o 
obj-$(CONFIG_X86_INTEL_MID)	+= pci-mid.o

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

drivers/pci/pci-pf-stub.c

0 → 100644
+54 −0
Original line number Diff line number Diff line 
// 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 "whitelist" 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_whitelist - 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_whitelist[] = {

	{ PCI_VDEVICE(AMAZON, 0x0053) },

	/* required last entry */

	{ 0 }

};

MODULE_DEVICE_TABLE(pci, pci_pf_stub_whitelist);



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_whitelist,

	.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");

include/linux/pci_ids.h

+2 −0
Original line number Diff line number Diff line
@@ -2552,6 +2552,8 @@ 
#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

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