linux/drivers/pci
Konrad Rzeszutek Wilk 51c71a3bba xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4).
The user has the option of disabling the platform driver:
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)

which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
and allow the PV drivers to take over. If the user wishes
to disable that they can set:

  xen_platform_pci=0
  (in the guest config file)

or
  xen_emul_unplug=never
  (on the Linux command line)

except it does not work properly. The PV drivers still try to
load and since the Xen platform driver is not run - and it
has not initialized the grant tables, most of the PV drivers
stumble upon:

input: Xen Virtual Keyboard as /devices/virtual/input/input5
input: Xen Virtual Pointer as /devices/virtual/input/input6M
------------[ cut here ]------------
kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
invalid opcode: 0000 [#1] SMP
Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
RIP: 0010:[<ffffffff813ddc40>]  [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
Call Trace:
 [<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
 [<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
 [<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
 [<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
 [<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
 [<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
 [<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
 [<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
 [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
 [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
 [<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
 [<ffffffff8145e7d9>] driver_attach+0x19/0x20
 [<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
 [<ffffffff8145f1ff>] driver_register+0x5f/0xf0
 [<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
 [<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
 [<ffffffffa0015000>] ? 0xffffffffa0014fff
 [<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
 [<ffffffff81002049>] do_one_initcall+0x49/0x170

.. snip..

which is hardly nice. This patch fixes this by having each
PV driver check for:
 - if running in PV, then it is fine to execute (as that is their
   native environment).
 - if running in HVM, check if user wanted 'xen_emul_unplug=never',
   in which case bail out and don't load any PV drivers.
 - if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
   does not exist, then bail out and not load PV drivers.
 - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=ide-disks',
   then bail out for all PV devices _except_ the block one.
   Ditto for the network one ('nics').
 - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=unnecessary'
   then load block PV driver, and also setup the legacy IDE paths.
   In (v3) make it actually load PV drivers.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <anthony.perard@citrix.com>
Reported-and-Tested-by: Fabio Fantoni <fabio.fantoni@m2r.biz>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: Add extra logic to handle the myrid ways 'xen_emul_unplug'
can be used per Ian and Stefano suggestion]
[v3: Make the unnecessary case work properly]
[v4: s/disks/ide-disks/ spotted by Fabio]
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> [for PCI parts]
CC: stable@vger.kernel.org
2014-01-03 14:54:18 -05:00
..
host PCI: mvebu: Return 'unsupported' for Interrupt Line and Interrupt Pin 2013-11-26 11:27:28 -07:00
hotplug PCI updates for v3.13: 2013-11-22 10:53:47 -08:00
pcie PCI updates for v3.13: 2013-11-22 10:53:47 -08:00
access.c PCI: Remove pcie_cap_has_devctl() 2013-08-28 20:51:39 -06:00
ats.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
bus.c PCI: Delay enabling bridges until they're needed 2013-07-25 12:35:03 -06:00
host-bridge.c PCI: add host bridge release support 2012-04-30 14:52:43 -06:00
hotplug-pci.c PCI: hotplug: remove pci_do_scan_bus() 2012-06-13 15:42:27 -06:00
htirq.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
ioapic.c ACPI: Eliminate the DEVICE_ACPI_HANDLE() macro 2013-11-14 23:17:21 +01:00
iov.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
irq.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
Kconfig PCI: remove ARCH_SUPPORTS_MSI kconfig option 2013-08-12 15:26:48 +00:00
Makefile pci: PCIe driver for Marvell Armada 370/XP systems 2013-05-20 19:18:44 +00:00
msi.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
of.c
pci-acpi.c PCI updates for v3.13: 2013-11-22 10:53:47 -08:00
pci-driver.c PCI: Disable Bus Master only on kexec reboot 2013-12-07 14:20:28 -07:00
pci-label.c ACPI: Eliminate the DEVICE_ACPI_HANDLE() macro 2013-11-14 23:17:21 +01:00
pci-stub.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
pci-sysfs.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
pci.c PCI / tg3: Give up chip reset and carrier loss handling if PCI device is not present 2013-12-02 16:01:49 -05:00
pci.h PCI: convert bus code to use dev_groups 2013-10-07 14:58:42 -06:00
probe.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
proc.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
quirks.c remove obsolete references to powertweak 2013-11-27 20:34:32 -08:00
remove.c PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev() 2013-11-25 14:39:58 -07:00
rom.c PCI: Add PCI ROM helper for platform-provided ROM images 2013-03-26 17:19:41 -06:00
search.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
setup-bus.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
setup-irq.c PCI: Provide a default pcibios_update_irq() 2012-09-18 17:28:21 -06:00
setup-res.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
slot.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
syscall.c PCI: Fix whitespace, capitalization, and spelling errors 2013-11-14 11:28:18 -07:00
vpd.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
xen-pcifront.c xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4). 2014-01-03 14:54:18 -05:00