Eric Lee / smarc-fsl-linux-kernel

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Commit c70e0d9dfef3d826c8ae4f7544acc53887cb161d

Authored by Chris Wright
Committed by Jesse Barnes
1 parent 2debb4d201

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>

Showing 3 changed files with 58 additions and 0 deletions Side-by-side Diff

... ... @@ -42,6 +42,15 @@
42 42  
43 43 When in doubt, say N.
44 44  
  45 +config PCI_STUB
  46 + tristate "PCI Stub driver"
  47 + depends on PCI
  48 + help
  49 + Say Y or M here if you want be able to reserve a PCI device
  50 + when it is going to be assigned to a guest operating system.
  51 +
  52 + When in doubt, say N.
  53 +
45 54 config HT_IRQ
46 55 bool "Interrupts on hypertransport devices"
47 56 default y
drivers/pci/Makefile
Diff comments   View file @ c70e0d9
... ... @@ -53,6 +53,8 @@
53 53  
54 54 obj-$(CONFIG_PCI_SYSCALL) += syscall.o
55 55  
  56 +obj-$(CONFIG_PCI_STUB) += pci-stub.o
  57 +
56 58 ifeq ($(CONFIG_PCI_DEBUG),y)
57 59 EXTRA_CFLAGS += -DDEBUG
58 60 endif
drivers/pci/pci-stub.c
Diff comments   View file @ c70e0d9
  1 +/* pci-stub - simple stub driver to reserve a pci device
  2 + *
  3 + * Copyright (C) 2008 Red Hat, Inc.
  4 + * Author:
  5 + * Chris Wright
  6 + *
  7 + * This work is licensed under the terms of the GNU GPL, version 2.
  8 + *
  9 + * Usage is simple, allocate a new id to the stub driver and bind the
  10 + * device to it. For example:
  11 + *
  12 + * # echo "8086 10f5" > /sys/bus/pci/drivers/pci-stub/new_id
  13 + * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
  14 + * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/pci-stub/bind
  15 + * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
  16 + * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/pci-stub
  17 + */
  18 +
  19 +#include <linux/module.h>
  20 +#include <linux/pci.h>
  21 +
  22 +static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
  23 +{
  24 + return 0;
  25 +}
  26 +
  27 +static struct pci_driver stub_driver = {
  28 + .name = "pci-stub",
  29 + .id_table = NULL, /* only dynamic id's */
  30 + .probe = pci_stub_probe,
  31 +};
  32 +
  33 +static int __init pci_stub_init(void)
  34 +{
  35 + return pci_register_driver(&stub_driver);
  36 +}
  37 +
  38 +static void __exit pci_stub_exit(void)
  39 +{
  40 + pci_unregister_driver(&stub_driver);
  41 +}
  42 +
  43 +module_init(pci_stub_init);
  44 +module_exit(pci_stub_exit);
  45 +
  46 +MODULE_LICENSE("GPL");
  47 +MODULE_AUTHOR("Chris Wright <chrisw@sous-sol.org>");