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Date:   Mon, 28 Nov 2022 19:05:43 +0000
From:   Sean Christopherson <seanjc@google.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     "Li, Xin3" <xin3.li@intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "hpa@zytor.com" <hpa@zytor.com>,
        "Tian, Kevin" <kevin.tian@intel.com>
Subject: Re: [RESEND PATCH 5/6] KVM: x86/VMX: add kvm_vmx_reinject_nmi_irq()
 for NMI/IRQ reinjection
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On Thu, Nov 24, 2022, Peter Zijlstra wrote:
> On Wed, Nov 23, 2022 at 08:42:51PM +0000, Sean Christopherson wrote:
> >  arch/x86/kvm/kvm_cache_regs.h | 16 +++++------
> >  arch/x86/kvm/vmx/vmenter.S    |  4 +--
> >  arch/x86/kvm/vmx/vmx.c        | 51 ++++++++++++++++++-----------------
> >  arch/x86/kvm/vmx/vmx.h        |  2 +-
> >  arch/x86/kvm/x86.h            |  6 ++---
> >  5 files changed, 41 insertions(+), 38 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
> > index c09174f73a34..af9bd0374915 100644
> > --- a/arch/x86/kvm/kvm_cache_regs.h
> > +++ b/arch/x86/kvm/kvm_cache_regs.h
> > @@ -50,26 +50,26 @@ BUILD_KVM_GPR_ACCESSORS(r15, R15)
> >   * 1	  0	  register in vcpu->arch
> >   * 1	  1	  register in vcpu->arch, needs to be stored back
> >   */
> > -static inline bool kvm_register_is_available(struct kvm_vcpu *vcpu,
> > -					     enum kvm_reg reg)
> > +static __always_inline bool kvm_register_is_available(struct kvm_vcpu *vcpu,
> > +						      enum kvm_reg reg)
> >  {
> >  	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
> >  }
> >  
> > -static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu,
> > -					 enum kvm_reg reg)
> > +static __always_inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu,
> > +						  enum kvm_reg reg)
> >  {
> >  	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
> >  }
> >  
> > -static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu,
> > -					       enum kvm_reg reg)
> > +static __always_inline void kvm_register_mark_available(struct kvm_vcpu *vcpu,
> > +							enum kvm_reg reg)
> >  {
> >  	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
> >  }
> >  
> > -static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu,
> > -					   enum kvm_reg reg)
> > +static __always_inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu,
> > +						    enum kvm_reg reg)
> >  {
> >  	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
> >  	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
> 
> You'll have to consider include/asm-generic/bitops/instrumented-non-atomic.h
> and friend, and the above should probably switch to using:
> 
>   arch_test_bit(), arch___set_bit() resp.
> 
> to avoid the explicit instrumentation.

Well that's just mean.  I'll figure out a solution, thanks for the heads up!