linux-kernel - Re: [PATCH] KVM: X86: Make fpu allocation a common function

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Date:   Mon, 14 Oct 2019 18:58:49 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Xiaoyao Li <xiaoyao.li@...el.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH] KVM: X86: Make fpu allocation a common function

Xiaoyao Li <xiaoyao.li@...el.com> writes:

> They are duplicated codes to create vcpu.arch.{user,guest}_fpu in VMX
> and SVM. Make them common functions.
>
> No functional change intended.

Would it rather make sense to move this code to
kvm_arch_vcpu_create()/kvm_arch_vcpu_destroy() instead?

>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
> ---
>  arch/x86/kvm/svm.c     | 20 +++-----------------
>  arch/x86/kvm/vmx/vmx.c | 20 +++-----------------
>  arch/x86/kvm/x86.h     | 26 ++++++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 34 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index e479ea9bc9da..0116a3c37a07 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2156,21 +2156,9 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
>  		goto out;
>  	}
>  
> -	svm->vcpu.arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,
> -						     GFP_KERNEL_ACCOUNT);
> -	if (!svm->vcpu.arch.user_fpu) {
> -		printk(KERN_ERR "kvm: failed to allocate kvm userspace's fpu\n");
> -		err = -ENOMEM;
> +	err = kvm_vcpu_create_fpu(&svm->vcpu);
> +	if (err)
>  		goto free_partial_svm;
> -	}
> -
> -	svm->vcpu.arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache,
> -						     GFP_KERNEL_ACCOUNT);
> -	if (!svm->vcpu.arch.guest_fpu) {
> -		printk(KERN_ERR "kvm: failed to allocate vcpu's fpu\n");
> -		err = -ENOMEM;
> -		goto free_user_fpu;
> -	}
>  
>  	err = kvm_vcpu_init(&svm->vcpu, kvm, id);
>  	if (err)
> @@ -2231,9 +2219,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
>  uninit:
>  	kvm_vcpu_uninit(&svm->vcpu);
>  free_svm:
> -	kmem_cache_free(x86_fpu_cache, svm->vcpu.arch.guest_fpu);
> -free_user_fpu:
> -	kmem_cache_free(x86_fpu_cache, svm->vcpu.arch.user_fpu);
> +	kvm_vcpu_free_fpu(&svm->vcpu);
>  free_partial_svm:
>  	kmem_cache_free(kvm_vcpu_cache, svm);
>  out:
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index e660e28e9ae0..53d9298ff648 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6710,21 +6710,9 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
>  	if (!vmx)
>  		return ERR_PTR(-ENOMEM);
>  
> -	vmx->vcpu.arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,
> -			GFP_KERNEL_ACCOUNT);
> -	if (!vmx->vcpu.arch.user_fpu) {
> -		printk(KERN_ERR "kvm: failed to allocate kvm userspace's fpu\n");
> -		err = -ENOMEM;
> +	err = kvm_vcpu_create_fpu(&vmx->vcpu);
> +	if (err)
>  		goto free_partial_vcpu;
> -	}
> -
> -	vmx->vcpu.arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache,
> -			GFP_KERNEL_ACCOUNT);
> -	if (!vmx->vcpu.arch.guest_fpu) {
> -		printk(KERN_ERR "kvm: failed to allocate vcpu's fpu\n");
> -		err = -ENOMEM;
> -		goto free_user_fpu;
> -	}
>  
>  	vmx->vpid = allocate_vpid();
>  
> @@ -6825,9 +6813,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
>  	kvm_vcpu_uninit(&vmx->vcpu);
>  free_vcpu:
>  	free_vpid(vmx->vpid);
> -	kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.guest_fpu);
> -free_user_fpu:
> -	kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.user_fpu);
> +	kvm_vcpu_free_fpu(&vmx->vcpu);
>  free_partial_vcpu:
>  	kmem_cache_free(kvm_vcpu_cache, vmx);
>  	return ERR_PTR(err);
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 45d82b8277e5..c27e7ac91337 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -367,4 +367,30 @@ static inline bool kvm_pat_valid(u64 data)
>  void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu);
>  void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu);
>  
> +static inline int kvm_vcpu_create_fpu(struct kvm_vcpu *vcpu)
> +{
> +	vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,
> +			GFP_KERNEL_ACCOUNT);
> +	if (!vcpu->arch.user_fpu) {
> +		printk(KERN_ERR "kvm: failed to allocate kvm userspace's fpu\n");
> +		return -ENOMEM;
> +	}
> +
> +	vcpu->arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache,
> +			GFP_KERNEL_ACCOUNT);
> +	if (!vcpu->arch.guest_fpu) {
> +		printk(KERN_ERR "kvm: failed to allocate vcpu's fpu\n");
> +		kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline void kvm_vcpu_free_fpu(struct kvm_vcpu *vcpu)
> +{
> +	kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);
> +	kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);
> +}
> +
>  #endif

-- 
Vitaly