linux-kernel - [PATCH RFC 0/6] KVM: x86: Interrupt-based mechanism for async

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Date:   Wed, 29 Apr 2020 11:36:28 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     x86@...nel.org, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: [PATCH RFC 0/6] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications

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 present' events.
This RFC does the later.

Please let me know what you think about the idea in general and the
selected approach in particular.

Vitaly Kuznetsov (6):
  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: 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

 Documentation/virt/kvm/cpuid.rst     |   6 ++
 Documentation/virt/kvm/msr.rst       |  52 +++++++++++--
 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      |   5 +-
 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/x86.c                   | 107 +++++++++++++++++++++------
 include/uapi/linux/kvm.h             |   1 +
 14 files changed, 228 insertions(+), 33 deletions(-)

-- 
2.25.3