[PATCH v2 0/6] KVM: MMU: fast invalid all mmio sptes

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

Changelog in v2:
  - rename kvm_mmu_invalid_mmio_spte to kvm_mmu_invalid_mmio_sptes
  - use kvm->memslots->generation as kvm global generation-number
  - fix comment and codestyle
  - init kvm generation close to mmio wrap-around value
  - keep kvm_mmu_zap_mmio_sptes

The current way is holding hot mmu-lock and walking all shadow pages, this
is not scale. This patchset tries to introduce a very simple and scale way
to fast invalid all mmio sptes - it need not walk any shadow pages and hold
any locks.

The idea is simple:
KVM maintains a global mmio invalid generation-number which is stored in
kvm->memslots.generation and every mmio spte stores the current global
generation-number into his available bits when it is created

When KVM need zap all mmio sptes, it just simply increase the global
generation-number. When guests do mmio access, KVM intercepts a MMIO #PF
then it walks the shadow page table and get the mmio spte. If the
generation-number on the spte does not equal the global generation-number,
it will go to the normal #PF handler to update the mmio spte

Since 19 bits are used to store generation-number on mmio spte, we zap all
mmio sptes when the number is round

Xiao Guangrong (6):
  KVM: MMU: retain more available bits on mmio spte
  KVM: MMU: store generation-number into mmio spte
  KVM: MMU: make return value of mmio page fault handler more readable
  KVM: MMU: fast invalid all mmio sptes
  KVM: MMU: add tracepoint for check_mmio_spte
  KVM: MMU: init kvm generation close to mmio wrap-around value

 arch/x86/include/asm/kvm_host.h |    3 +-
 arch/x86/kvm/mmu.c              |  134 +++++++++++++++++++++++++++++++--------
 arch/x86/kvm/mmu.h              |   17 +++++
 arch/x86/kvm/mmutrace.h         |   34 +++++++++-
 arch/x86/kvm/paging_tmpl.h      |   10 ++-
 arch/x86/kvm/vmx.c              |   12 +++-
 arch/x86/kvm/x86.c              |   11 +++-
 virt/kvm/kvm_main.c             |    6 ++
 8 files changed, 186 insertions(+), 41 deletions(-)

-- 
1.7.7.6