Xen balloon driver will update ballooned out pages' P2M entries to point
to scratch page for PV guests. In 24f69373e2 ("xen/balloon: don't alloc
page while non-preemptible", kmap_flush_unused was moved after updating
P2M table. In that case for 32 bit PV guest we might end up with

  P2M    X -----> S  (S is mfn of balloon scratch page)
  M2P    Y -----> X  (Y is mfn in persistent kmap entry)

kmap_flush_unused() iterates through all the PTEs in the kmap address
space, using pte_to_page() to obtain the page. If the p2m and the m2p
are inconsistent the incorrect page is returned.  This will clear
page->address on the wrong page which may cause subsequent oopses if
that page is currently kmap'ed.

Move the flush back between get_page and __set_phys_to_machine to fix
this.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: stable@vger.kernel.org # 3.12+

Pull Xen bugfixes from Konrad Rzeszutek Wilk:
 "This has an healthy amount of code being removed - which we do not use
  anymore (the only user of it was ia64 Xen which had been removed
  already).  The other bug-fixes are to make Xen ARM be able to use the
  new event channel mechanism and proper export of header files to
  user-space.

  Summary:
   - Fix ARM and Xen FIFO not working.
   - Remove more Xen ia64 vestigates.
   - Fix UAPI missing Xen files"

* tag 'stable/for-linus-3.14-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  ia64/xen: Remove Xen support for ia64 even more
  xen: install xen/gntdev.h and xen/gntalloc.h
  xen/events: bind all new interdomain events to VCPU0

Commit d52eefb47d4e ("ia64/xen: Remove Xen support for ia64") removed
the Kconfig symbol XEN_XENCOMM. But it didn't remove the code depending
on that symbol. Remove that code now.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Commit fc087e10734a4d3e40693fc099461ec1270b3fff (xen/events: remove
unnecessary init_evtchn_cpu_bindings()) causes a regression.

The kernel-side VCPU binding was not being correctly set for newly
allocated or bound interdomain events.  In ARM guests where 2-level
events were used, this would result in no interdomain events being
handled because the kernel-side VCPU masks would all be clear.

x86 guests would work because the irq affinity was set during irq
setup and this would set the correct kernel-side VCPU binding.

Fix this by properly initializing the kernel-side VCPU binding in
bind_evtchn_to_irq().

Reported-and-tested-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "Bug-fixes:
   - Revert "xen/grant-table: Avoid m2p_override during mapping" as it
     broke Xen ARM build.
   - Fix CR4 not being set on AP processors in Xen PVH mode"

* tag 'stable/for-linus-3.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvh: set CR4 flags for APs
  Revert "xen/grant-table: Avoid m2p_override during mapping"

This reverts commit 08ece5bb2312b4510b161a6ef6682f37f4eac8a1.

As it breaks ARM builds and needs more attention
on the ARM side.

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

Pull Xen bugfixes from Konrad Rzeszutek Wilk:
 "Bug-fixes for the new features that were added during this cycle.

  There are also two fixes for long-standing issues for which we have a
  solution: grant-table operations extra work that was not needed
  causing performance issues and the self balloon code was too
  aggressive causing OOMs.

  Details:
   - Xen ARM couldn't use the new FIFO events
   - Xen ARM couldn't use the SWIOTLB if compiled as 32-bit with 64-bit PCIe devices.
   - Grant table were doing needless M2P operations.
   - Ratchet down the self-balloon code so it won't OOM.
   - Fix misplaced kfree in Xen PVH error code paths"

* tag 'stable/for-linus-3.14-rc0-late-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvh: Fix misplaced kfree from xlated_setup_gnttab_pages
  drivers: xen: deaggressive selfballoon driver
  xen/grant-table: Avoid m2p_override during mapping
  xen/gnttab: Use phys_addr_t to describe the grant frame base address
  xen: swiotlb: handle sizeof(dma_addr_t) != sizeof(phys_addr_t)
  arm/xen: Initialize event channels earlier

Current xen-selfballoon driver is too aggressive which may cause OOM be
triggered more often. Eg. this bug reported by James:
https://lkml.org/lkml/2013/11/21/158

There are two mainly reasons:
1) The original goal_page didn't consider some pages used by kernel space, like
slab pages and pages used by device drivers.

2) The balloon driver may not give back memory to guest OS fast enough when the
workload suddenly aquries a lot of physical memory.

In both cases, the guest OS will suffer from memory pressure and OOM may
be triggered.

The fix is make xen-selfballoon driver not that aggressive by adding extra 10%
of total ram pages to goal_page.
It's more valuable to keep the guest system reliable and response faster than
balloon out these 10% pages to XEN.

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the original functions were renamed to __gnttab_[un]map_refs, with a new
  parameter m2p_override
- based on m2p_override either they follow the original behaviour, or just set
  the private flag and call set_phys_to_machine
- gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
  m2p_override false
- a new function gnttab_[un]map_refs_userspace provides the old behaviour

It also removes a stray space from page.h and change ret to 0 if
XENFEAT_auto_translated_physmap, as that is the only possible return value
there.

v2:
- move the storing of the old mfn in page->index to gnttab_map_refs
- move the function header update to a separate patch

v3:
- a new approach to retain old behaviour where it needed
- squash the patches into one

v4:
- move out the common bits from m2p* functions, and pass pfn/mfn as parameter
- clear page->private before doing anything with the page, so m2p_find_override
  won't race with this

v5:
- change return value handling in __gnttab_[un]map_refs
- remove a stray space in page.h
- add detail why ret = 0 now at some places

v6:
- don't pass pfn to m2p* functions, just get it locally

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

On ARM, address size can be 32 bits or 64 bits (if CONFIG_ARCH_PHYS_ADDR_T_64BIT
is enabled).
We can't assume that the grant frame base address will always fits in an
unsigned long. Use phys_addr_t instead of unsigned long as argument for
gnttab_setup_auto_xlat_frames.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>