[PATCH v4 00/17] kvm: x86: Support AMD SVM AVIC w/ in-kernel irqchip mode

[Suthikulpanit, Suravee]

The 'commit 67034bb9dd5e ("KVM: SVM: Add irqchip_split() checks before
enabling AVIC")' was introduced to fix miscellaneous boot-hang issues
when enable AVIC. This is mainly due to AVIC hardware doest not #vmexit
on write to LAPIC EOI register resulting in-kernel PIC and IOAPIC to
wait and do not inject new interrupts (e.g. PIT, RTC).

This limits AVIC to only work with kernel_irqchip=split mode, which is
not currently enabled by default, and also required user-space to
support split irqchip model, which might not be the case.

The goal of this series is to enable AVIC to work in both irqchip modes,
by allowing AVIC to be deactivated temporarily during runtime, and fallback
to legacy interrupt injection mode (w/ vINTR and interrupt windows)
when needed, and then re-enabled subsequently.

Similar approach is also used to handle Hyper-V SynIC in the
'commit 5c919412fe61 ("kvm/x86: Hyper-V synthetic interrupt controller")',
where APICv is permanently disabled at runtime (currently broken for
AVIC, and fixed by this series). 

This series contains serveral parts:
  * Part 1: patch 1,2
    Code clean up, refactor, and introduce helper funtions

  * Part 2: patch 3 
    Introduce APICv deactivate bits to keep track of APICv state 
    for each vm.
 
  * Part 3: patch 4-9
    Add support for activate/deactivate APICv at runtime

  * Part 4: patch 10-13:
    Add support various cases where APICv needs to be deactivated

  * Part 5: patch 14-16:
    Introduce in-kernel IOAPIC workaround for AVIC EOI

  * Part 6: path 17
    Allow enable AVIC w/ kernel_irqchip=on

Pre-requisite Patch:
  * commit b9c6ff94e43a ("iommu/amd: Re-factor guest virtual APIC (de-)activation code")
    (https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/
     ?h=next&id=b9c6ff94e43a0ee053e0c1d983fba1ac4953b762)

This series has been tested against v5.3 as following:
  * Booting Linux and Windows Server 2019 VMs upto 240 vcpus
    and FreeBSD upto 128 vcpus w/ qemu option "kernel-irqchip=on"
    and "-no-hpet".
  * Pass-through Intel 10GbE NIC and run netperf in the VM.

Changes from V3: (https://lkml.org/lkml/2019/9/13/871)
(Per Paolo comments) 
  * Replace struct kvm_vcpu with struct kvm in various interfaces
  * Replace KVM_REQ_APICV_ACTIVATE/DEACTIVATE with KVM_REQ_APICV_UPDATE request
  * Replace APICv state enum (introduced in V3) w/ deactivate bits to track APICv state
  * Remove kvm_apicv_eoi_accelerate() (introduced in V3)
  * Deactivate APICv when using PIT re-inject mode
  * Consolidate srcu_read_unlock/lock into svm_request_update_avic()

Suravee Suthikulpanit (17):
  kvm: x86: Modify kvm_x86_ops.get_enable_apicv() to use struct kvm parameter
  kvm: lapic: Introduce APICv update helper function
  kvm: x86: Introduce APICv deactivate bits
  kvm: x86: Add support for activate/de-activate APICv at runtime
  kvm: x86: Add APICv activate/deactivate request trace points
  kvm: x86: svm: Add support to activate/deactivate posted interrupts
  svm: Add support for setup/destroy virutal APIC backing page for AVIC
  kvm: x86: Introduce APICv pre-update hook
  svm: Add support for activate/deactivate AVIC at runtime
  kvm: x86: hyperv: Use APICv update request interface
  svm: Deactivate AVIC when launching guest with nested SVM support
  svm: Temporary deactivate AVIC during ExtINT handling
  kvm: i8254: Deactivate APICv when using in-kernel PIT re-injection mode.
  kvm: lapic: Clean up APIC predefined macros
  kvm: ioapic: Refactor kvm_ioapic_update_eoi()
  kvm: ioapic: Lazy update IOAPIC EOI
  svm: Allow AVIC with in-kernel irqchip mode

 arch/x86/include/asm/kvm_host.h |  18 ++++-
 arch/x86/kvm/hyperv.c           |   5 +-
 arch/x86/kvm/i8254.c            |  10 +++
 arch/x86/kvm/ioapic.c           | 149 +++++++++++++++++++++++++---------------
 arch/x86/kvm/lapic.c            |  35 ++++++----
 arch/x86/kvm/lapic.h            |   2 +
 arch/x86/kvm/svm.c              | 136 +++++++++++++++++++++++++++++++-----
 arch/x86/kvm/trace.h            |  19 +++++
 arch/x86/kvm/vmx/vmx.c          |   6 +-
 arch/x86/kvm/x86.c              |  61 +++++++++++++---
 10 files changed, 343 insertions(+), 98 deletions(-)

-- 
1.8.3.1