[PATCH 0/8] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications

[Vitaly Kuznetsov]

Concerns were expressed around (ab)using #PF for KVM's async_pf mechanism,
it seems that re-using #PF exception for a PV mechanism wasn't a great
idea after all. The Grand Plan is to switch to using e.g. #VE for 'page
not present' events and normal APIC interrupts for 'page ready' events.
This series does the later.

Changes since RFC:
- Using #PF for 'page ready' is deprecated and removed [Paolo Bonzini]
- 'reason' field in 'struct kvm_vcpu_pv_apf_data' is not used for 'page ready'
  notifications and 'pageready_token' is not used for 'page not present' events
  [Paolo Bonzini]
- Renamed MSR_KVM_ASYNC_PF2 -> MSR_KVM_ASYNC_PF_INT [Peter Xu]
- Drop 'enabled' field from MSR_KVM_ASYNC_PF_INT [Peter Xu]
- Other minor changes supporting the above.

Vitaly Kuznetsov (8):
  Revert "KVM: async_pf: Fix #DF due to inject "Page not Present" and
    "Page Ready" exceptions simultaneously"
  KVM: x86: extend struct kvm_vcpu_pv_apf_data with token info
  KVM: introduce kvm_read_guest_offset_cached()
  KVM: x86: interrupt based APF page-ready event delivery
  KVM: x86: acknowledgment mechanism for async pf page ready
    notifications
  KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT
  KVM: x86: Switch KVM guest to using interrupts for page ready APF
    delivery
  KVM: x86: drop KVM_PV_REASON_PAGE_READY case from
    kvm_handle_page_fault()

 Documentation/virt/kvm/cpuid.rst     |   6 ++
 Documentation/virt/kvm/msr.rst       | 106 ++++++++++++++------
 arch/s390/include/asm/kvm_host.h     |   2 +
 arch/x86/entry/entry_32.S            |   5 +
 arch/x86/entry/entry_64.S            |   5 +
 arch/x86/include/asm/hardirq.h       |   3 +
 arch/x86/include/asm/irq_vectors.h   |   6 +-
 arch/x86/include/asm/kvm_host.h      |   7 +-
 arch/x86/include/asm/kvm_para.h      |   6 ++
 arch/x86/include/uapi/asm/kvm_para.h |  11 ++-
 arch/x86/kernel/irq.c                |   9 ++
 arch/x86/kernel/kvm.c                |  42 ++++++--
 arch/x86/kvm/cpuid.c                 |   3 +-
 arch/x86/kvm/mmu/mmu.c               |  10 +-
 arch/x86/kvm/x86.c                   | 142 ++++++++++++++++++---------
 include/linux/kvm_host.h             |   3 +
 include/uapi/linux/kvm.h             |   1 +
 virt/kvm/async_pf.c                  |  10 ++
 virt/kvm/kvm_main.c                  |  19 +++-
 19 files changed, 295 insertions(+), 101 deletions(-)

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2.25.4