Commit c70e0d9d authored by Chris Wright's avatar Chris Wright Committed by Jesse Barnes
Browse files

PCI: pci-stub module to reserve pci device 



When doing device assignment with KVM there's currently nothing to
protect the device from having a driver in the host as well as the guest.
This trivial module just binds the pci device on the host to a stub
driver so that a real host driver can't bind to the device.  It has no
pci id table, it supports only dynamic ids.

 # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
 # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
 # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
 # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
 lrwxrwxrwx 1 root root 0 2008-11-25 19:10 /sys/bus/pci/devices/0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub

Cc: "Kay, Allen M" <allen.m.kay@intel.com>
Cc: "Nakajima, Jun" <jun.nakajima@intel.com>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 2debb4d2

drivers/pci/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -42,6 +42,15 @@ config PCI_DEBUG 


	  When in doubt, say N.



config PCI_STUB

	tristate "PCI Stub driver"

	depends on PCI

	help

	  Say Y or M here if you want be able to reserve a PCI device

	  when it is going to be assigned to a guest operating system.



	  When in doubt, say N.



config HT_IRQ

	bool "Interrupts on hypertransport devices"

	default y

drivers/pci/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ obj-$(CONFIG_HOTPLUG) += setup-bus.o 


obj-$(CONFIG_PCI_SYSCALL) += syscall.o



obj-$(CONFIG_PCI_STUB) += pci-stub.o



ifeq ($(CONFIG_PCI_DEBUG),y)

EXTRA_CFLAGS += -DDEBUG

endif

drivers/pci/pci-stub.c

0 → 100644
+47 −0
Original line number Diff line number Diff line 
/* pci-stub - simple stub driver to reserve a pci device

 *

 * Copyright (C) 2008 Red Hat, Inc.

 * Author:

 * 	Chris Wright

 *

 * This work is licensed under the terms of the GNU GPL, version 2.

 *

 * Usage is simple, allocate a new id to the stub driver and bind the

 * device to it.  For example:

 * 

 * # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id

 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind

 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind

 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver

 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub

 */



#include <linux/module.h>

#include <linux/pci.h>



static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)

{

	return 0;

}



static struct pci_driver stub_driver = {

	.name		= "pci-stub",

	.id_table	= NULL,	/* only dynamic id's */

	.probe		= pci_stub_probe,

};



static int __init pci_stub_init(void)

{

	return pci_register_driver(&stub_driver);

}



static void __exit pci_stub_exit(void)

{

	pci_unregister_driver(&stub_driver);

}



module_init(pci_stub_init);

module_exit(pci_stub_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");

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