[PATCH 0/8] s390/kvm fixes

[Christian Borntraeger <borntraeger@de.ibm.com>]

Gleb, Paolo, Marcelo,

here are some low level changes to kvm on s390 that we have been
cooking for a while now.

Patch "s390/pgtable: fix ipte notify bit" will go via Martins
tree into 3.10, but is included to reduce the amount of merge
conflicts. 

Patch "s390: fix gmap_ipte_notifier vs. software dirty pages"
will also go via Martins tree into 3.10 and it fixes a hang with
heavy host paging and KVM. This is optional for merging, but
makes testing on kvm/next easier.

This series addresses 2 problems:
- paging of guest prefix page
- RCU timeouts

The first problem is basically that we must not have the host pte
invalid or r/o for the guest prefix pages. (everything else has fully
nested paging but the prefix page must not cause host faults).
It is not enough to pin the page, also the pte has to be r/w all the
time. Mlocking is not enough due to memory compaction, malicious
unmapping etc.
We use the existing callback mechanism of the s390 page table functions
to kick guests out of SIE and hold them until this is done. We cant 
use the existing kick functions since we must hold a pgste lock while
we wait for SIE to exit and IPIs might dead lock.

The second problem is that with KVM on s390 we have seen very long
RCU stalls due to SIE not exiting on interrupts. Instead of returning
to SIE, we now force an exit into the kvm module, which then does the
guest exit/enter magic, fixing rcu.

The whole bunch is probably too complex for 3.10, so please queue for
3.11

Christian Borntraeger (5):
  s390/pgtable: fix ipte notify bit
  s390/kvm: Mark if a cpu is in SIE
  s390/kvm: Provide a way to prevent reentering SIE
  s390/kvm: Kick guests out of sie if prefix page host pte is touched
  s390: fix gmap_ipte_notifier vs. software dirty pages

Martin Schwidefsky (3):
  s390/kvm: fix psw rewinding in handle_skey
  s390/kvm: rename RCP_xxx defines to PGSTE_xxx
  s390/kvm: avoid automatic sie reentry

 arch/s390/include/asm/kvm_host.h |  8 +++-
 arch/s390/include/asm/pgtable.h  | 83 +++++++++++++++++++---------------------
 arch/s390/kernel/asm-offsets.c   |  3 ++
 arch/s390/kernel/entry64.S       | 80 ++++++++++++++++++--------------------
 arch/s390/kvm/intercept.c        | 39 +------------------
 arch/s390/kvm/kvm-s390.c         | 81 ++++++++++++++++++++++++++++++++++++++-
 arch/s390/kvm/kvm-s390.h         |  5 +++
 arch/s390/kvm/priv.c             |  3 +-
 arch/s390/mm/pgtable.c           |  5 +--
 9 files changed, 179 insertions(+), 128 deletions(-)

-- 
1.8.1.4