linux-kernel - Re: [PATCH v2 7/8] KVM: x86: remove SMRAM address space if SMM is not supported

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Date:   Mon, 24 Oct 2022 15:33:01 +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 7/8] KVM: x86: remove SMRAM address space if SMM is
 not supported

On Thu, 2022-09-29 at 13:20 -0400, Paolo Bonzini wrote:
> If CONFIG_KVM_SMM is not defined HF_SMM_MASK will always be zero, and
> we can spare userspace the hassle of setting up the SMRAM address space
> simply by reporting that only one address space is supported.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  arch/x86/include/asm/kvm_host.h | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index cb88da02d965..d11697504471 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1994,11 +1994,14 @@ enum {
>  #define HF_SMM_MASK		(1 << 6)
>  #define HF_SMM_INSIDE_NMI_MASK	(1 << 7)
>  
> -#define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
> -#define KVM_ADDRESS_SPACE_NUM 2
> -
> -#define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
> -#define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
> +#ifdef CONFIG_KVM_SMM
> +# define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
> +# define KVM_ADDRESS_SPACE_NUM 2
> +# define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
> +# define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
> +#else
> +# define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0)
> +#endif
>  
>  #define KVM_ARCH_WANT_MMU_NOTIFIER
>  

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

Best regards,
	Maxim Levitsky