Which disables in the ticketlock slowpath the Xen PV optimization's.
Useful for diagnosing issues and comparing benchmarks in
over-commit CPU scenarios.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

On hosts with more than 168 GB of memory, a 32-bit guest may attempt
to grant map an MFN that is error cannot lookup in its mapping of the
m2p table.  There is an m2p lookup as part of m2p_add_override() and
m2p_remove_override().  The lookup falls off the end of the mapped
portion of the m2p and (because the mapping is at the highest virtual
address) wraps around and the lookup causes a fault on what appears to
be a user space address.

do_page_fault() (thinking it's a fault to a userspace address), tries
to lock mm->mmap_sem.  If the gntdev device is used for the grant map,
m2p_add_override() is called from from gnttab_mmap() with mm->mmap_sem
already locked.  do_page_fault() then deadlocks.

The deadlock would most commonly occur when a 64-bit guest is started
and xenconsoled attempts to grant map its console ring.

Introduce mfn_to_pfn_no_overrides() which checks the MFN is within the
mapped portion of the m2p table before accessing the table and use
this in m2p_add_override(), m2p_remove_override(), and mfn_to_pfn()
(which already had the correct range check).

All faults caused by accessing the non-existant parts of the m2p are
thus within the kernel address space and exception_fixup() is called
without trying to lock mm->mmap_sem.

This means that for MFNs that are outside the mapped range of the m2p
then mfn_to_pfn() will always look in the m2p overrides.  This is
correct because it must be a foreign MFN (and the PFN in the m2p in
this case is only relevant for the other domain).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
--
v3: check for auto_translated_physmap in mfn_to_pfn_no_overrides()
v2: in mfn_to_pfn() look in m2p_overrides if the MFN is out of
    range as it's probably foreign.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

get_balloon_scratch_page() disables preemption so we cannot call
alloc_page() in between get/put_balloon_scratch_page().  Shuffle bits
around in decrease_reservation() to avoid this.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen_init_spinlocks() currently calls static_key_slow_inc() before
jump_label_init() is invoked. When CONFIG_JUMP_LABEL is set (which usually is
the case) the effect of this static_key_slow_inc() is deferred until after
jump_label_init(). This is different from when CONFIG_JUMP_LABEL is not set, in
which case the key is set immediately. Thus, depending on the value of config
option, we may observe different behavior.

In addition, when we come to __jump_label_transform() from jump_label_init(),
the key (paravirt_ticketlocks_enabled) is already enabled. On processors where
ideal_nop is not the same as default_nop this will cause a BUG() since it is
expected that before a key is enabled the latter is replaced by the former
during initialization.

To address this problem we need to move
static_key_slow_inc(&paravirt_ticketlocks_enabled) so that it is called
after jump_label_init(). We also need to make sure that this is done before
other cpus start to boot. early_initcall appears to be  a good place to do so.
(Note that we cannot move whole xen_init_spinlocks() there since pv_lock_ops
need to be set before alternative_instructions() runs.)
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: Added extra comments in the code]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

Upon deeper review it was agreed to remove the driver-unique
'locality' sysfs attribute before it is present in a released
kernel.

The attribute was introduced in e2683957
during the 3.12 merge window, so this patch needs to go in before
3.12 is released.

The hope is to have a well defined locality API that all the other
locality aware drivers can use, perhaps in 3.13.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

All the default durations were being set to 10 minutes which is
way too long for the timeouts. Normal values for the longest
duration are around 5 mins, and short duration ar around .5s.

Further, these are just the default, tpm_get_timeouts will set
them to values from the TPM (or throw an error).

Just remove them.
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The BUG_ON in increase_reservation is wrong as we have P2M entry
ballooned out page set to balloon scratch page, so it might have a valid
P2M entry at that point.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

In decrease_reservation(), if the kernel is preempted between updating
the mapping and updating the p2m then they may end up using different
scratch pages.

Use get_balloon_scratch_page() and put_balloon_scratch_page() which use
get_cpu_var() and put_cpu_var() to correctly disable preemption.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>

As we get compile warnings about .init.data being
used by non-init functions.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This reverts commit 70dd4998.

Now that the bugs have been resolved we can re-enable the
PV ticketlock implementation under PVHVM Xen guests.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>

There is no need to setup this kicker IPI if we are never going
to use the paravirtualized ticketlock mechanism.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>

Before this patch we would patch all of the pv_lock_ops sites
using alternative assembler. Then later in the bootup cycle
change the unlock_kick and lock_spinning to the Xen specific -
without re patching.

That meant that for the core of the kernel we would be running
with the baremetal version of unlock_kick and lock_spinning while
for modules we would have the proper Xen specific slowpaths.

As most of the module uses some API from the core kernel that ended
up with slowpath lockers waiting forever to be kicked (b/c they
would be using the Xen specific slowpath logic). And the
kick never came b/c the unlock path that was taken was the
baremetal one.

On PV we do not have the problem as we initialise before the
alternative code kicks in.

The fix is to make the updating of the pv_lock_ops function
be done before the alternative code starts patching.

Note that this patch fixes issues discovered by commit
f10cd522.
("xen: disable PV spinlocks on HVM") wherein it mentioned

   PV spinlocks cannot possibly work with the current code because they are
   enabled after pvops patching has already been done, and because PV
   spinlocks use a different data structure than native spinlocks so we
   cannot switch between them dynamically.

The first problem is solved by this patch.

The second problem has been solved by commit
816434ec
(Merge branch 'x86-spinlocks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip)

P.S.
There is still the commit 70dd4998
(xen/spinlock: Disable IRQ spinlock (PV) allocation on PVHVM) to
revert but that can be done later after all other bugs have been
fixed.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>

As we are using the generic ticketlock structs and these
old structures are not needed anymore.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>

The xen_lock_spinning has a check for the kicker interrupts
and if it is not initialized it will spin normally (not enter
the slowpath).

But for PVHVM case we would initialize the kicker interrupt
before the CPU came online. This meant that if the booting
CPU used a spinlock and went in the slowpath - it would
enter the slowpath and block forever. The forever part because
during bootup: the spinlock would be taken _before_ the CPU
sets itself to be online (more on this further), and we enter
to poll on the event channel forever.

The bootup CPU (see commit fc78d343
"xen/smp: initialize IPI vectors before marking CPU online"
for details) and the CPU that started the bootup consult
the cpu_online_mask to determine whether the booting CPU should
get an IPI. The booting CPU has to set itself in this mask via:

  set_cpu_online(smp_processor_id(), true);

However, if the spinlock is taken before this (and it is) and
it polls on an event channel - it will never be woken up as
the kernel will never send an IPI to an offline CPU.

Note that the PVHVM logic in sending IPIs is using the HVM
path which has numerous checks using the cpu_online_mask
and cpu_active_mask. See above mention git commit for details.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>

Linux 3.11-rc7

As we need the git commit 28817e9de4f039a1a8c1fe1df2fa2df524626b9e
Author: Chuck Anderson <chuck.anderson@oracle.com>
Date:   Tue Aug 6 15:12:19 2013 -0700

    xen/smp: initialize IPI vectors before marking CPU online

* tag 'v3.11-rc7': (443 commits)
  Linux 3.11-rc7
  ARC: [lib] strchr breakage in Big-endian configuration
  VFS: collect_mounts() should return an ERR_PTR
  bfs: iget_locked() doesn't return an ERR_PTR
  efs: iget_locked() doesn't return an ERR_PTR()
  proc: kill the extra proc_readfd_common()->dir_emit_dots()
  cope with potentially long ->d_dname() output for shmem/hugetlb
  usb: phy: fix build breakage
  USB: OHCI: add missing PCI PM callbacks to ohci-pci.c
  staging: comedi: bug-fix NULL pointer dereference on failed attach
  lib/lz4: correct the LZ4 license
  memcg: get rid of swapaccount leftovers
  nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection
  nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error
  drivers/platform/olpc/olpc-ec.c: initialise earlier
  ipv4: expose IPV4_DEVCONF
  ipv6: handle Redirect ICMP Message with no Redirected Header option
  be2net: fix disabling TX in be_close()
  Revert "ACPI / video: Always call acpi_video_init_brightness() on init"
  Revert "genetlink: fix family dump race"
  ...
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Merge branch 'x86/spinlocks' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into stable/for-linus-3.12

* 'x86/spinlocks' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kvm/guest: Fix sparse warning: "symbol 'klock_waiting' was not declared as static"
  kvm: Paravirtual ticketlocks support for linux guests running on KVM hypervisor
  kvm guest: Add configuration support to enable debug information for KVM Guests
  kvm uapi: Add KICK_CPU and PV_UNHALT definition to uapi
  xen, pvticketlock: Allow interrupts to be enabled while blocking
  x86, ticketlock: Add slowpath logic
  jump_label: Split jumplabel ratelimit
  x86, pvticketlock: When paravirtualizing ticket locks, increment by 2
  x86, pvticketlock: Use callee-save for lock_spinning
  xen, pvticketlocks: Add xen_nopvspin parameter to disable xen pv ticketlocks
  xen, pvticketlock: Xen implementation for PV ticket locks
  xen: Defer spinlock setup until boot CPU setup
  x86, ticketlock: Collapse a layer of functions
  x86, ticketlock: Don't inline _spin_unlock when using paravirt spinlocks
  x86, spinlock: Replace pv spinlocks with pv ticketlocks

When linux is running as dom0, Xen doesn't show the physical cpu but a
virtual CPU.
On some ARM SOC (for instance the exynos 5250), linux registers callbacks
for cpuidle and cpufreq. When these callbacks are called, they will modify
directly the physical cpu not the virtual one. It can impact the whole board
instead of only dom0.
Signed-off-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

m2p_remove_override() calls get_balloon_scratch_page() in
MULTI_update_va_mapping() even though it already has pointer to this page from
the earlier call (in scratch_page). This second call doesn't have a matching
put_balloon_scratch_page() thus not restoring preempt count back. (Also, there
is no put_balloon_scratch_page() in the error path.)

In addition, the second multicall uses __xen_mc_entry() which does not disable
interrupts. Rearrange xen_mc_* calls to keep interrupts off while performing
multicalls.

This commit fixes a regression introduced by:

commit ee072640
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date:   Tue Jul 23 17:23:54 2013 +0000

    xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

xen_pm_init was unconditionally setting pm_power_off and arm_pm_restart
function pointers. This breaks multi-platform kernels. Make this
conditional on running as a Xen guest and make it a late_initcall to
ensure it is setup after platform code for Dom0.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: stable@vger.kernel.org

kzalloc already adds this __GFP_ZERO.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Randy reports:

x86_64:

drivers/built-in.o: In function `xen_tpmfront_init':
xen-tpmfront.c:(.init.text+0x257c): undefined reference to `xenbus_register_frontend'

This is nicely fixed by selecting the XenBus frontend module.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In commit cd9151e2: xen/balloon: set a mapping for ballooned out pages
we have the ballooned out page's mapping set to a scratch page.

That commit also sets the P2M entry of ballooned out page to the scratch
page's MFN. This is necessary for PV guest but not for HVM guest. On the
other hand, setting the P2M entry would trigger BUG_ON in
__set_phys_to_machine.

The correct thing to do here is to avoid calling __set_phys_to_machine
for auto translated guest.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

The call to del_evtchn() frees "evtchn".
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When a foreign mapper attempts to map guest frames that are paged out,
the mapper receives an ENOENT response and will have to try again
while a helper process pages the target frame back in.

Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries
of mapping calls.

Permit subsequent calls to update a sub-range of the VMA, iff nothing
is yet mapped in that range.

Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only
set vma->vm_private_data if the parameters are valid and (if
necessary) the pages for the auto_translated_physmap case have been
allocated.  This prevents subsequent calls from incorrectly entering
the 'retry' path when there are no pages allocated etc.
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull staging fixes from Greg KH:
 "Here are two tiny staging tree fixes (well, one is for an iio driver,
  but those updates come through the staging tree due to dependancies)

  One fixes a problem with an IIO driver, and the other fixes a bug in
  the comedi driver core"

* tag 'staging-3.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: comedi: bug-fix NULL pointer dereference on failed attach
  iio: adjd_s311: Fix non-scan mode data read

Pull USB fixes from Greg KH:
 "Here are two USB fixes for 3.11-rc7

  One fixes a reported regression in the OHCI driver, and the other
  fixes a reported build breakage in the USB phy drivers"

* tag 'usb-3.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: phy: fix build breakage
  USB: OHCI: add missing PCI PM callbacks to ohci-pci.c

Pull ARM fixes from Russell King:
 "This round of fixes is smaller than previous: a couple more updates
  for the security fixes, and a one-liner kexec fix"

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7816/1: CONFIG_KUSER_HELPERS: fix help text
  ARM: 7815/1: kexec: offline non panic CPUs on Kdump panic
  ARM: 7819/1: fiq: Cast the first argument of flush_icache_range()

Pull vfs fixes from Al Viro:
 "Assorted fixes from the last week or so"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  VFS: collect_mounts() should return an ERR_PTR
  bfs: iget_locked() doesn't return an ERR_PTR
  efs: iget_locked() doesn't return an ERR_PTR()
  proc: kill the extra proc_readfd_common()->dir_emit_dots()
  cope with potentially long ->d_dname() output for shmem/hugetlb

Pull ACPI fix from Rafael Wysocki:
 "I really hoped that it wouldn't be necessary to change anything in
  ACPI at this point, but it turns out that we need to revert one more
  ACPI video commit causing trouble.

  This reverts a change in the ACPI video driver that caused the ACPI
  backlight initialization to be carried out even if acpi_backlight=vendor
  is passed in the kernel command line which turns out to break things
  at least on one system"

* tag 'acpi-3.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "ACPI / video: Always call acpi_video_init_brightness() on init"

Pull SCSI fixes from James Bottomley:
 "This is a set of small bug fixes for lpfc and zfcp and a fix for a
  fairly nasty bug in sg where a process which cancels I/O completes in
  a kernel thread which would then try to write back to the now gone
  userspace and end up writing to a random kernel address instead"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] zfcp: remove access control tables interface (keep sysfs files)
  [SCSI] zfcp: fix schedule-inside-lock in scsi_device list loops
  [SCSI] zfcp: fix lock imbalance by reworking request queue locking
  [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
  [SCSI] lpfc: Don't force CONFIG_GENERIC_CSUM on

For a search buffer, 2 byte aligned, strchr() was returning pointer
outside of buffer (buf - 1)

------------->8----------------
    // Input buffer (default 4 byte aigned)
    char *buffer = "1AA_";

    // actual search start (to mimick 2 byte alignment)
    char *current_line = &(buffer[2]);

    // Character to search for
    char c = 'A';

    char *c_pos = strchr(current_line, c);

    printf("%s\n", c_pos) --> 'AA_' as oppose to 'A_'
------------->8----------------
Reported-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Debugged-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Cc: <stable@vger.kernel.org> # [3.9 and 3.10]
Cc: Noam Camus <noamc@ezchip.com>
Signed-off-by: Joern Rennecke  <joern.rennecke@embecosm.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This should actually be returning an ERR_PTR on error instead of NULL.
That was how it was designed and all the callers expect it.

[AV: actually, that's what "VFS: Make clone_mnt()/copy_tree()/collect_mounts()
return errors" missed - originally collect_mounts() was expected to return
NULL on failure]

Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

iget_locked() returns a NULL on error, it doesn't return an ERR_PTR.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The iget_locked() function returns NULL on error and never an ERR_PTR.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

proc_readfd_common() does dir_emit_dots() twice in a row,
we need to do this only once.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

dynamic_dname() is both too much and too little for those - the
output may be well in excess of 64 bytes dynamic_dname() assumes
to be enough (thanks to ashmem feeding really long names to
shmem_file_setup()) and vsnprintf() is an overkill for those
guys.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull libata fixes from Tejun Heo:
 "This contains three commits all of which are updates for specific
  devices which aren't too widespread.  Pretty limited scope and nothing
  too interesting or dangerous"

* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  sata_fsl: save irqs while coalescing
  libata: apply behavioral quirks to sil3826 PMP
  sata, highbank: fix ordering of SGPIO signals

Pull cgroup fix from Tejun Heo:
 "A late fix for cgroup.

  This fixes a behavior regression visible to userland which was created
  by a commit merged during -rc1.  While the behavior change isn't too
  likely to be noticeable, the fix is relatively low risk and we'll need
  to backport it through -stable anyway if the bug gets released"

* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: fix a regression in validating config change

Pull drm fixes from Dave Airlie:
 "Ben was on holidays for a week so a few nouveau regression fixes
  backed up, but they all seem necessary.

  Otherwise one i915 and one gma500 fix"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  gma500: Fix SDVO turning off randomly
  drm/nv04/disp: fix framebuffer pin refcounting
  drm/nouveau/mc: fix race condition between constructor and request_irq()
  drm/nouveau: fix reclocking on nv40
  drm/nouveau/ltcg: fix allocating memory as free
  drm/nouveau/ltcg: fix ltcg memory initialization after suspend
  drm/nouveau/fb: fix null derefs in nv49 and nv4e init
  drm/i915: Invalidate TLBs for the rings after a reset