linux/drivers/block
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
..
aoe aoe: do not BUG if memory pressure prevented debugfs file creation 2013-09-11 15:59:28 -07:00
drbd drbd: avoid to shrink max_bio_size due to peer re-configuration 2013-11-08 09:10:29 -07:00
mtip32xx mtip32xx: dynamically allocate buffer in debugfs functions 2013-11-08 09:10:28 -07:00
paride block_device_operations->release() should return void 2013-05-07 02:16:21 -04:00
rsxx rsxx: Fix possible kernel panic with invalid config. 2013-11-08 09:10:29 -07:00
xen-blkback xen/blkback: fix reference counting 2013-11-08 09:10:27 -07:00
DAC960.c procfs: new helper - PDE_DATA(inode) 2013-04-09 14:13:32 -04:00
DAC960.h
Kconfig Merge branch 'for-3.13/post-mq-drivers' into for-linus 2013-11-14 08:29:01 -07:00
Makefile Merge branch 'for-3.13/post-mq-drivers' into for-linus 2013-11-14 08:29:01 -07:00
amiflop.c tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
ataflop.c block_device_operations->release() should return void 2013-05-07 02:16:21 -04:00
brd.c block: fix a probe argument to blk_register_region 2013-11-08 08:59:39 -07:00
cciss.c tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
cciss.h cciss: Adds simple mode functionality 2011-08-08 11:40:15 +02:00
cciss_cmd.h cciss: use new doorbell-bit-5 reset method 2011-05-06 08:23:55 -06:00
cciss_scsi.c cciss: switch to ->show_info() 2013-04-09 14:13:19 -04:00
cciss_scsi.h cciss: add cciss_tape_cmds module paramter 2011-05-06 08:23:59 -06:00
cpqarray.c cpqarray: fix info leak in ida_locked_ioctl() 2013-09-24 17:00:26 -07:00
cpqarray.h
cryptoloop.c move linux/loop.h to drivers/block 2013-06-29 12:46:45 +04:00
floppy.c block: make rq->cmd_flags be 64-bit 2013-10-25 11:55:59 +01:00
hd.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
ida_cmd.h
ida_ioctl.h
loop.c loop: fix crash when using unassigned loop device 2013-11-08 09:10:28 -07:00
loop.h move linux/loop.h to drivers/block 2013-06-29 12:46:45 +04:00
mg_disk.c mg_disk: remove deprecated IRQF_DISABLED 2013-11-08 09:10:27 -07:00
nbd.c nbd: correct disconnect behavior 2013-07-03 16:08:05 -07:00
null_blk.c Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2013-12-24 10:06:03 -08:00
nvme-core.c DMA-API: block: nvme-core: replace dma_set_mask()+dma_set_coherent_mask() with new helper 2013-09-21 21:02:24 +01:00
nvme-scsi.c NVMe: Use kzalloc instead of kmalloc+memset 2013-06-19 13:24:27 -04:00
osdblk.c block: replace strict_strtoul() with kstrtoul() 2013-09-11 15:56:56 -07:00
pktcdvd.c pktcdvd: debugfs functions return NULL on error 2013-11-08 09:10:31 -07:00
ps3disk.c Drivers: block: remove __dev* attributes. 2013-01-03 15:57:15 -08:00
ps3vram.c procfs: new helper - PDE_DATA(inode) 2013-04-09 14:13:32 -04:00
rbd.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2013-09-19 12:50:37 -05:00
rbd_types.h rbd: get rid of RBD_MAX_SEG_NAME_LEN 2012-12-17 08:37:29 -06:00
skd_main.c drivers: block: Mark the functions as static in skd_main.c 2013-12-19 08:06:49 -07:00
skd_s1120.h skd: fix formatting in skd_s1120.h 2013-11-08 09:10:30 -07:00
smart1,2.h fix typos 'comamnd' -> 'command' in comments 2011-02-02 11:31:21 +01:00
sunvdc.c sunvdc: Fix off-by-one in generic_request(). 2013-02-14 11:49:01 -08:00
swim.c drivers/block/swim.c: remove unnecessary platform_set_drvdata() 2013-09-11 15:56:59 -07:00
swim3.c block_device_operations->release() should return void 2013-05-07 02:16:21 -04:00
swim_asm.S
sx8.c block, sx8: fix pointer math issue getting fw version 2012-03-03 19:44:39 +01:00
umem.c Drivers: block: remove __dev* attributes. 2013-01-03 15:57:15 -08:00
umem.h
virtio_blk.c virtio-blk: virtqueue_kick() must be ordered with other virtqueue operations 2013-11-19 19:00:45 -07:00
xen-blkfront.c xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4). 2014-01-03 14:54:18 -05:00
xsysace.c xilinx systemace: Fix sparse warnings 2013-07-10 07:47:12 +02:00
z2ram.c block_device_operations->release() should return void 2013-05-07 02:16:21 -04:00