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

Xiao Guangrong
2013-04-01T09:57:01Z

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(-)

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1.7.7.6