xen: make remove callback of xen driver void returned

Since commit fc7a6209d571 ("bus: Make remove callback return void")
forces bus_type::remove be void-returned, it doesn't make much sense for
any bus based driver implementing remove callbalk to return non-void to
its caller.

This change is for xen bus based drivers.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: switch gnttab_end_foreign_access() to take a struct page pointer

Instead of a virtual kernel address use a pointer of the associated
struct page as second parameter of gnttab_end_foreign_access().

Most users have that pointer available already and are creating the
virtual address from it, risking problems in case the memory is
located in highmem.

gnttab_end_foreign_access() itself won't need to get the struct page
from the address again.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/grant-table: remove readonly parameter from functions

The gnttab_end_foreign_access() family of functions is taking a
"readonly" parameter, which isn't used. Remove it from the function
parameters.

Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: add "not_essential" flag to struct xenbus_driver

When booting the xenbus driver will wait for PV devices to have
connected to their backends before continuing. The timeout is different
between essential and non-essential devices.

Non-essential devices are identified by their nodenames directly in the
xenbus driver, which requires to update this list in case a new device
type being non-essential is added (this was missed for several types
in the past).

In order to avoid this problem, add a "not_essential" flag to struct
xenbus_driver which can be set to "true" by the respective frontend.

Set this flag for the frontends currently regarded to be not essential
(vkbs and vfb) and use it for testing in the xenbus driver.

Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211022064800.14978-2-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Input: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200707180857.GA30600@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: introduce input_mt_report_slot_inactive()

input_mt_report_slot_state() ignores "tool" argument when the slot is
closed, which has caused a bit of confusion. Let's introduce
input_mt_report_slot_inactive() to report inactive slot state.

Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Link: https://lore.kernel.org/r/20200508055656.96389-2-jiada_wang@mentor.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case, I placed the "fall through"
part at the beginning of the code comment, which is what GCC is
expecting to find.

Addresses-Coverity-ID: 114757 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - allow better run-time configuration

It is now only possible to control if multi-touch virtual device
is created or not (via the corresponding XenStore entries),
but keyboard and pointer devices are always created.
In some cases this is not desirable. For example, if virtual
keyboard device is exposed to Android then the latter won't
automatically show on-screen keyboard as it expects that a
physical keyboard device can be used for typing.

Utilize keyboard and pointer device XenStore feature fields to
configure which virtual devices are created:
- set "feature-disable-keyboard" to 1 if no keyboard device
needs to be created
- set "feature-disable-pointer" to 1 if no pointer device
needs to be created
Keep old behavior by default.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Suggested-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
Tested-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - fix multi-touch XenStore node's locations

kbdif protocol describes multi-touch device parameters as a
part of frontend's XenBus configuration nodes while they
belong to backend's configuration. Fix this by reading the
parameters as defined by the protocol.

Fixes: 49aac8204da5 ("Input: xen-kbdfront - add multi-touch support")

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - do not advertise multi-touch pressure support

Some user-space applications expect multi-touch pressure
on contact to be reported if it is advertised in device
properties. Otherwise, such applications may treat reports
not as actual touches, but hovering. Currently this is
only advertised, but not reported.
Fix this by not advertising that ABS_MT_PRESSURE is supported.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
Patchwork-Id: 10140017
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - enable auto repeat for xen keyboard frontend driver

Long pressed key could not show right in XEN vncviewer after tigervnc
client changed the way how to send repeat keys, from "Down Up Down Up
..." to "Down Down ... Up". This will report autorepeat to input by
checking if same key being pressed, and let handler process it finally.

Signed-off-by: Liang Yan <lyan@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - add multi-touch support

Extend xen_kbdfront to provide multi-touch support to unprivileged domains.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
[dtor: factor out various sub-protocols - multitouch, single touch, keys]
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - use string constants from PV protocol

Xen input para-virtual protocol defines string constants
used by both back and frontend. Use those instead of
explicit strings in the frontend driver.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen-kbdfront - add module parameter for setting resolution

Add a parameter for setting the resolution of xen-kbdfront in order to
be able to cope with a (virtual) frame buffer of arbitrary resolution.

While at it remove the pointless second reading of parameters from
Xenstore in the device connection phase: all parameters are available
during device probing already and that is where they should be read.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: convert remaining uses of pr_warning to pr_warn

To enable eventual removal of pr_warning

This makes pr_warn use consistent for drivers/input

Prior to this patch, there were 8 uses of pr_warning and
17 uses of pr_warn in drivers/input

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

xen: make use of xenbus_read_unsigned() in xen-kbdfront

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: dmitry.torokhov@gmail.com
Cc: linux-input@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>

Input: xen-kbdfront - prefer xenbus_write() over xenbus_printf() where possible

... as being the simpler variant.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: xen - check return value of xenbus_printf

Internally, xenbus_printf uses memory allocation, so it can fail under
memory pressure, leaving the input device configured as absolute with the
backend supplying relative coordinates.

Signed-off-by: Insu Yun <wuninsu@gmail.com>
Reviewed-by: Julien Grall <julien.grall@citrix.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

xen: Use correctly the Xen memory terminologies

Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.

For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.

For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.

Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.

Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.

[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend

xenkbd_disconnect_backend doesn't free grant table entry. This bug affects
live migration.

xenkbd_disconnect_backend uses gnttab_end_foreign_access_ref to handle
grant table entry which doesn't really free an entry.

Thus every time we do xenkbd_resume, grant table entry increses by one. As
an grant table entry occupies 8 bytes, an grant table page has at most 512
entries. Every 512 times we do xenkdb_resume, grant table pages increses by
one.

After around 3500 times of live migration, grant table pages will increase
by 7, causing too many pages to populate and hitting max_pages limit when
assigning pages.Thus assign_pages will fail, so will live migration.

Signed-off-by: Chang Huaixin <huaixin.chx@alibaba-inc.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

xen: remove DEFINE_XENBUS_DRIVER() macro

The DEFINE_XENBUS_DRIVER() macro looks a bit weird and causes sparse
errors.

Replace the uses with standard structure definitions instead. This is
similar to pci and usb device registration.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>

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

Input: remove use of __devinit

CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

xen-kbdfront: handle backend CLOSED without CLOSING

Backend drivers shouldn't transistion to CLOSED unless the frontend is
CLOSED. If a backend does transition to CLOSED too soon then the
frontend may not see the CLOSING state and will not properly shutdown.

So, treat an unexpected backend CLOSED state the same as CLOSING.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Xen: consolidate and simplify struct xenbus_driver instantiation

The 'name', 'owner', and 'mod_name' members are redundant with the
identically named fields in the 'driver' sub-structure. Rather than
switching each instance to specify these fields explicitly, introduce
a macro to simplify this.

Eliminate further redundancy by allowing the drvname argument to
DEFINE_XENBUS_DRIVER() to be blank (in which case the first entry from
the ID table will be used for .driver.name).

Also eliminate the questionable xenbus_register_{back,front}end()
wrappers - their sole remaining purpose was the checking of the
'owner' field, proper setting of which shouldn't be an issue anymore
when the macro gets used.

v2: Restore DRV_NAME for the driver name in xen-pciback.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Input: xen-kbdfront - enable driver for HVM guests

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Input: xen-kbdfront - fix mouse getting stuck after save/restore

Mouse gets "stuck" after restore of PV guest but buttons are in working
condition.

If driver has been configured for ABS coordinates at start it will get
XENKBD_TYPE_POS events and then suddenly after restore it'll start getting
XENKBD_TYPE_MOTION events, that will be dropped later and they won't get
into user-space.

Regression was introduced by hunk 5 and 6 of
5ea5254aa0ad269cfbd2875c973ef25ab5b5e9db
("Input: xen-kbdfront - advertise either absolute or relative
coordinates").

Driver on restore should ask xen for request-abs-pointer again if it is
available. So restore parts that did it before 5ea5254.

Acked-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
[v1: Expanded the commit description]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Input: xen-kbdfront - move to drivers/input/misc

drivers/input is reserved for input core code and input handlers with
drivers belonging to one of the sub-directories.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>