linux-kernel - Re: [PATCH v2 8/8] KVM: x86: do not define KVM_REQ

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Date:   Mon, 24 Oct 2022 15:33:07 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     seanjc@...gle.com, maciej.szmigiero@...cle.com
Subject: Re: [PATCH v2 8/8] KVM: x86: do not define KVM_REQ_SMI if SMM
 disabled

On Thu, 2022-09-29 at 13:20 -0400, Paolo Bonzini wrote:
> This ensures that all the relevant code is compiled out, in fact
> the process_smi stub can be removed too.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  arch/x86/include/asm/kvm_host.h | 2 ++
>  arch/x86/kvm/smm.h              | 1 -
>  arch/x86/kvm/x86.c              | 6 ++++++
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index d11697504471..d58d4a62b227 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -81,7 +81,9 @@
>  #define KVM_REQ_NMI			KVM_ARCH_REQ(9)
>  #define KVM_REQ_PMU			KVM_ARCH_REQ(10)
>  #define KVM_REQ_PMI			KVM_ARCH_REQ(11)
> +#ifdef CONFIG_KVM_SMM
>  #define KVM_REQ_SMI			KVM_ARCH_REQ(12)
> +#endif
>  #define KVM_REQ_MASTERCLOCK_UPDATE	KVM_ARCH_REQ(13)
>  #define KVM_REQ_MCLOCK_INPROGRESS \
>  	KVM_ARCH_REQ_FLAGS(14, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
> diff --git a/arch/x86/kvm/smm.h b/arch/x86/kvm/smm.h
> index 7ccce6b655ca..a6795b93ba30 100644
> --- a/arch/x86/kvm/smm.h
> +++ b/arch/x86/kvm/smm.h
> @@ -28,7 +28,6 @@ void process_smi(struct kvm_vcpu *vcpu);
>  static inline int kvm_inject_smi(struct kvm_vcpu *vcpu) { return -ENOTTY; }
>  static inline bool is_smm(struct kvm_vcpu *vcpu) { return false; }
>  static inline void kvm_smm_changed(struct kvm_vcpu *vcpu, bool in_smm) { WARN_ON_ONCE(1); }
> -static inline void process_smi(struct kvm_vcpu *vcpu) { WARN_ON_ONCE(1); }
>  
>  /*
>   * emulator_leave_smm is used as a function pointer, so the
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index e22184bad92b..ba5661ee3fd7 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5020,8 +5020,10 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
>  
>  	process_nmi(vcpu);
>  
> +#ifdef CONFIG_KVM_SMM
>  	if (kvm_check_request(KVM_REQ_SMI, vcpu))
>  		process_smi(vcpu);
> +#endif
>  
>  	/*
>  	 * KVM's ABI only allows for one exception to be migrated.  Luckily,
> @@ -10194,8 +10196,10 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  		}
>  		if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
>  			record_steal_time(vcpu);
> +#ifdef CONFIG_KVM_SMM
>  		if (kvm_check_request(KVM_REQ_SMI, vcpu))
>  			process_smi(vcpu);
> +#endif
>  		if (kvm_check_request(KVM_REQ_NMI, vcpu))
>  			process_nmi(vcpu);
>  		if (kvm_check_request(KVM_REQ_PMU, vcpu))
> @@ -12539,7 +12543,9 @@ bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
>  		return true;
>  
>  	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
> +#ifdef CONFIG_KVM_SMM
>  		kvm_test_request(KVM_REQ_SMI, vcpu) ||
> +#endif
>  		 kvm_test_request(KVM_REQ_EVENT, vcpu))
>  		return true;
>  

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
	Maxim Levitsky