linux-kernel - RE: [PATCH 0/7] KVM: VMX: Handle NMI VM-Exits in noinstr section

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Date:   Wed, 18 Jan 2023 19:14:39 +0000
From:   "Li, Xin3" <xin3.li@...el.com>
To:     "Christopherson,, Sean" <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
CC:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "Lutomirski, Andy" <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: RE: [PATCH 0/7] KVM: VMX: Handle NMI VM-Exits in noinstr section

Sean,

Is this merged into x86 KVM tree?

Thanks!
    Xin

> -----Original Message-----
> From: Sean Christopherson <seanjc@...gle.com>
> Sent: Monday, December 12, 2022 10:09 PM
> To: Christopherson,, Sean <seanjc@...gle.com>; Paolo Bonzini
> <pbonzini@...hat.com>
> Cc: kvm@...r.kernel.org; linux-kernel@...r.kernel.org; Peter Zijlstra
> <peterz@...radead.org>; Lutomirski, Andy <luto@...nel.org>; Thomas Gleixner
> <tglx@...utronix.de>
> Subject: [PATCH 0/7] KVM: VMX: Handle NMI VM-Exits in noinstr section
> 
> Move NMI VM-Exit handling into vmx_vcpu_enter_exit() to fix a (mostly
> benign?) bug where NMIs can be unblocked prior to servicing the NMI that
> triggered the VM-Exit, e.g. if instrumentation triggers a fault and thus an IRET.  I
> deliberately didn't tag any of these for stable@ as the odds of me screwing
> something up or of a backport going sideways seems higher than out-of-order
> NMIs causing major problems.
> 
> The bulk of this series is just getting various helpers/paths ready for noinstr
> usage.
> 
> I kept the use of a direct call to a dedicated entry point for NMIs (doubled down
> really).  AFAICT, there are no issues with the direct call in the current code, and I
> don't know enough about FRED to know if using INT $2 would be better or worse,
> i.e. less churn seemed like the way to go.  And if reverting to INT $2 in the future
> is desirable, splitting NMI and IRQ handling makes it quite easy to do so as all the
> relevant code that needs to be ripped out is isolated.
> 
> Sean Christopherson (7):
>   KVM: x86: Make vmx_get_exit_qual() and vmx_get_intr_info()
>     noinstr-friendly
>   KVM: VMX: Allow VM-Fail path of VMREAD helper to be instrumented
>   KVM: VMX: Always inline eVMCS read/write helpers
>   KVM: VMX: Always inline to_vmx() and to_kvm_vmx()
>   x86/entry: KVM: Use dedicated VMX NMI entry for 32-bit kernels too
>   KVM: VMX: Provide separate subroutines for invoking NMI vs. IRQ
>     handlers
>   KVM: VMX: Handle NMI VM-Exits in noinstr region
> 
>  arch/x86/include/asm/idtentry.h | 16 +++-----
>  arch/x86/kernel/nmi.c           |  8 ++--
>  arch/x86/kvm/kvm_cache_regs.h   | 12 ++++++
>  arch/x86/kvm/vmx/hyperv.h       | 20 ++++-----
>  arch/x86/kvm/vmx/vmcs.h         |  4 +-
>  arch/x86/kvm/vmx/vmenter.S      | 72 ++++++++++++++++++---------------
>  arch/x86/kvm/vmx/vmx.c          | 55 +++++++++++++------------
>  arch/x86/kvm/vmx/vmx.h          | 18 ++++-----
>  arch/x86/kvm/vmx/vmx_ops.h      |  2 +
>  arch/x86/kvm/x86.h              |  6 +--
>  10 files changed, 117 insertions(+), 96 deletions(-)
> 
> 
> base-commit: 208f1c64e255fe3a29083880818e010ebdf585c6
> --
> 2.39.0.rc1.256.g54fd8350bd-goog