commit fa41ba0d08de7c975c3e94d0067553f9b934221f upstream.

Right now there is a potential hang situation for postcopy migrations,
if the guest is enabling storage keys on the target system during the
postcopy process.

For storage key virtualization, we have to forbid the empty zero page as
the storage key is a property of the physical page frame.  As we enable
storage key handling lazily we then drop all mappings for empty zero
pages for lazy refaulting later on.

This does not work with the postcopy migration, which relies on the
empty zero page never triggering a fault again in the future. The reason
is that postcopy migration will simply read a page on the target system
if that page is a known zero page to fault in an empty zero page.  At
the same time postcopy remembers that this page was already transferred
- so any future userfault on that page will NOT be retransmitted again
to avoid races.

If now the guest enters the storage key mode while in postcopy, we will
break this assumption of postcopy.

The solution is to disable the empty zero page for KVM guests early on
and not during storage key enablement. With this change, the postcopy
migration process is guaranteed to start after no zero pages are left.

As guest pages are very likely not empty zero pages anyway the memory
overhead is also pretty small.

While at it this also adds proper page table locking to the zero page
removal.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull MIPS fixes from Ralf Baechle:
 "The two indirect syscall fixes have sat in linux-next for a few days.
  I did check back with a hardware designer to ensure a SYNC is really
  what's required for the GIC fix and so the GIC fix didn't make it into
  to linux-next in time for this final pull request.

  It builds in local build tests and passes Imagination's test system"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  irqchip: mips-gic: SYNC after enabling GIC region
  MIPS: Remove pt_regs adjustments in indirect syscall handler
  MIPS: seccomp: Fix indirect syscall args

Pull x86 fixes from Thomas Gleixner:

 - Expand the space for uncompressing as the LZ4 worst case does not fit
   into the currently reserved space

 - Validate boot parameters more strictly to prevent out of bound access
   in the decompressor/boot code

 - Fix off by one errors in get_segment_base()

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Prevent faulty bootparams.screeninfo from causing harm
  x86/boot: Provide more slack space during decompression
  x86/ldt: Fix off by one in get_segment_base()

Pull ARM SoC fixes from Olof Johansson:
 "A couple of late-arriving fixes before final 4.13:

   - A few reverts of DT bindings on Allwinner for their ethernet
     driver. Discussion didn't converge, and since bindings are
     considered ABI it makes sense to revert instead of having to
     support two bindings long-term.

   - A fix to enumerate GPIOs properly on Marvell Armada AP806"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm64: dts: marvell: fix number of GPIOs in Armada AP806 description
  arm: dts: sunxi: Revert EMAC changes
  arm64: dts: allwinner: Revert EMAC changes
  dt-bindings: net: Revert sun8i dwmac binding

mvebu fixes for 4.13 (part 3)

Fix number of GPIOs in AP806 description for Armada 7K/8K

* tag 'mvebu-fixes-4.13-3' of git://git.infradead.org/linux-mvebu:
  arm64: dts: marvell: fix number of GPIOs in Armada AP806 description

Signed-off-by: Olof Johansson <olof@lixom.net>

Pull s390 fixes from Martin Schwidefsky:
 "Three more bug fixes for v4.13.

  The two memory management related fixes are quite new, they fix kernel
  crashes that can be triggered by user space.

  The third commit fixes a bug in the vfio ccw translation code"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/mm: fix BUG_ON in crst_table_upgrade
  s390/mm: fork vs. 5 level page tabel
  vfio: ccw: fix bad ptr math for TIC cda translation

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and are now bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.

Changed since v1 (Linus Torvalds)
    - remove now useless kvm_arch_mmu_notifier_invalidate_page()

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Tested-by: Mike Galbraith <efault@gmx.de>
Tested-by: Adam Borowski <kilobyte@angband.pl>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and now are bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Alistair Popple <alistair@popple.id.au>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

A 31-bit compat process can force a BUG_ON in crst_table_upgrade
with specific, invalid mmap calls, e.g.

   mmap((void*) 0x7fff8000, 0x10000, 3, 32, -1, 0)

The arch_get_unmapped_area[_topdown] functions miss an if condition
in the decision to do a page table upgrade.

Fixes: 9b11c7912d00 ("s390/mm: simplify arch_get_unmapped_area[_topdown]")
Cc: <stable@vger.kernel.org>  # v4.12+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

The mm->context.asce field of a new process is not set up correctly
in case of a fork with a 5 level page table.
Add the missing case to init_new_context().

Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>