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

Vitaly Kuznetsov
2020-05-11T16:48:03Z

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