Re: [PATCH v5 00/18] kvm: x86: Support AMD SVM AVIC w/ in-kernel irqchip mode

Suravee Suthikulpanit
2020-01-02T10:18:06Z

Paolo,

Ping. Would you please let me know your feedback when you get a chance to review this series

Thanks,
Suravee

On 11/15/19 3:15 AM, Suravee Suthikulpanit wrote:
> 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 (a.k.a Dynamic APICv).
>
> 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 several parts:
> * Part 1: patch 1,2
> Code clean up, refactor, and introduce helper functions
>
> * Part 2: patch 3
> Introduce APICv deactivate bits to keep track of APICv state
> for each vm.
>
> * Part 3: patch 4-10
> Add support for activate/deactivate APICv at runtime
>
> * Part 4: patch 11-14:
> Add support for various cases where APICv needs to
> be deactivated
>
> * Part 5: patch 15-17:
> Introduce in-kernel IOAPIC workaround for AVIC EOI
>
> * Part 6: path 18
> 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, FreeBSD, and Windows Server 2019 VMs upto 240 vcpus
> w/ qemu option "kernel-irqchip=on" and "-no-hpet".
> * Pass-through Intel 10GbE NIC and run netperf in the VM.
>
> Changes from V4: (https://lkml.org/lkml/2019/11/1/764)
> * Rename APICV_DEACT_BIT_xxx to APICV_INHIBIT_REASON_xxxx
> * Introduce kvm_x86_ops.check_apicv_inhibit_reasons hook
> to allow vendors to specify which APICv inhibit reason bits
> to support (patch 08/18).
> * Update comment on kvm_request_apicv_update() no-lock requirement.
> (patch 04/18)
>
> Suravee Suthikulpanit (18):
> 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 inhibit reason bits
> kvm: x86: Add support for dynamic APICv
> kvm: x86: Add APICv (de)activate request trace points
> kvm: x86: svm: Add support to (de)activate posted interrupts
> svm: Add support for setup/destroy virutal APIC backing page for AVIC
> kvm: x86: Introduce APICv x86 ops for checking APIC inhibit reasons
> kvm: x86: Introduce x86 ops hook for pre-update APICv
> svm: Add support for dynamic APICv
> 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 | 19 ++++-
> arch/x86/kvm/hyperv.c | 5 +-
> arch/x86/kvm/i8254.c | 12 +++
> arch/x86/kvm/ioapic.c | 149 +++++++++++++++++++++++-------------
> arch/x86/kvm/lapic.c | 35 +++++----
> arch/x86/kvm/lapic.h | 2 +
> arch/x86/kvm/svm.c | 164 +++++++++++++++++++++++++++++++++++-----
> arch/x86/kvm/trace.h | 19 +++++
> arch/x86/kvm/vmx/vmx.c | 12 ++-
> arch/x86/kvm/x86.c | 71 ++++++++++++++---
> 10 files changed, 385 insertions(+), 103 deletions(-)
>