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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: Chris Wright <chrisw@sous-sol.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
hifive-unleashed-5.1
Chris Wright 2008-11-25 21:17:13 -08:00 committed by Jesse Barnes
parent 2debb4d201
commit c70e0d9dfe
3 changed files with 58 additions and 0 deletions
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9
drivers/pci/Kconfig
View File

@ -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

2
drivers/pci/Makefile
View File

@ -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

47
drivers/pci/pci-stub.c 100644
View File

@ -0,0 +1,47 @@
/* 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>");