linux/drivers/char
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
..
agp parisc: agp/parisc-agp: allow binding of user memory to the AGP GART 2013-07-31 23:42:00 +02:00
hw_random Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-11-23 16:18:25 -08:00
ipmi BMC support for PARISC machines 2013-09-05 08:34:32 -07:00
mwave mwave: fix info leak in mwave_ioctl() 2013-07-09 10:33:28 -07:00
pcmcia pcmcia: synclink_cs: replace sum of bitmasks with OR operation. 2013-07-26 17:59:07 -07:00
tpm xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4). 2014-01-03 14:54:18 -05:00
xilinx_hwicap char: hwicap: Remove unnecessary dev_set_drvdata() 2013-10-03 16:03:31 -07:00
apm-emulation.c
applicom.c applicom: use correct array offset 2013-03-15 12:23:48 -07:00
applicom.h
bfin-otp.c
bsr.c drivers: clean-up prom.h implicit includes 2013-10-09 20:04:04 -05:00
ds1302.c
ds1620.c ds1620: single_open() leak 2013-05-05 00:11:29 -04:00
dsp56k.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
dtlk.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
efirtc.c rtc: single_open() leaks 2013-05-05 00:12:29 -04:00
generic_nvram.c
genrtc.c rtc: single_open() leaks 2013-05-05 00:12:29 -04:00
hangcheck-timer.c
hpet.c drivers/char/hpet.c: allow user controlled mmap for user processes 2013-11-13 12:09:11 +09:00
i8k.c drivers/char/i8k.c: add Dell XPLS L421X 2013-12-04 20:22:40 -08:00
Kconfig drivers/char/hpet.c: allow user controlled mmap for user processes 2013-11-13 12:09:11 +09:00
lp.c Char: lp, protect LPGETSTATUS with port_mutex 2013-05-16 18:08:58 -07:00
Makefile IPMI: Change link order 2012-10-16 18:07:12 -07:00
mbcs.c char: remove use of __devinitconst 2012-11-21 12:55:19 -08:00
mbcs.h
mem.c /dev/oldmem: Remove the interface 2013-07-03 16:08:03 -07:00
misc.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-11-13 15:34:18 +09:00
mmtimer.c drivers/char/mmtimer.c: Remove useless kfree 2012-09-26 13:20:40 -07:00
msm_smd_pkt.c
mspec.c char: Use vma_pages() to replace (vm_end - vm_start) >> PAGE_SHIFT 2013-05-21 10:07:54 -07:00
nsc_gpio.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
nvram.c
nwbutton.c various char drivers: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
nwbutton.h
nwflash.c Merge branch 'late/fixes' into fixes 2012-10-07 07:22:32 -07:00
pc8736x_gpio.c pc8736x_gpio: use platform_device_unregister in pc8736x_gpio_cleanup() 2012-10-24 15:52:29 -07:00
ppdev.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
ps3flash.c ps3flash: switch to generic_file_llseek_size() 2013-06-29 12:57:33 +04:00
random.c The /dev/random changes for 3.13 including a number of improvements in 2013-11-16 10:19:15 -08:00
raw.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
rtc.c various char drivers: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
scx200_gpio.c
snsc_event.c various char drivers: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
snsc.c various char drivers: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
snsc.h
sonypi.c ACPI: Remove the old /proc/acpi/event interface 2013-07-15 13:56:36 +02:00
tb0219.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
tile-srom.c PTR_RET() is a weird name, and led to some confusing usage. We ended 2013-09-04 17:31:11 -07:00
tlclk.c tlclk: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
toshiba.c
ttyprintk.c ttyprintk: Fix NULL pointer deref by setting tty_port ops after initializing port 2013-05-21 10:13:23 -07:00
uv_mmtimer.c
virtio_console.c virtio_console: verify if queue is broken after virtqueue_get_buf() 2013-10-29 11:28:18 +10:30