linux-kernel - Re: [PATCH v2] KVM: x86: get rid of odd out jump label in pdptrs

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Message-ID: <365321df-2f66-95ef-4bf3-4e250f0a99a7@redhat.com>
Date:   Fri, 25 Oct 2019 13:46:51 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Miaohe Lin <linmiaohe@...wei.com>, rkrcmar@...hat.com,
        sean.j.christopherson@...el.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com
Cc:     x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] KVM: x86: get rid of odd out jump label in
 pdptrs_changed

Queued, thanks (but it likely won't be on git.kernel.org until after the
end of KVM Forum, sorry about that).

Paolo

On 25/10/19 12:54, Miaohe Lin wrote:
> The odd out jump label is really not needed. Get rid of
> it by return true directly while r < 0 as suggested by
> Paolo. This further lead to var changed being unused.
> Remove it too.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> ---
>  arch/x86/kvm/x86.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ff395f812719..8b0d594a3b90 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -721,7 +721,6 @@ EXPORT_SYMBOL_GPL(load_pdptrs);
>  bool pdptrs_changed(struct kvm_vcpu *vcpu)
>  {
>  	u64 pdpte[ARRAY_SIZE(vcpu->arch.walk_mmu->pdptrs)];
> -	bool changed = true;
>  	int offset;
>  	gfn_t gfn;
>  	int r;
> @@ -738,11 +737,9 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu)
>  	r = kvm_read_nested_guest_page(vcpu, gfn, pdpte, offset, sizeof(pdpte),
>  				       PFERR_USER_MASK | PFERR_WRITE_MASK);
>  	if (r < 0)
> -		goto out;
> -	changed = memcmp(pdpte, vcpu->arch.walk_mmu->pdptrs, sizeof(pdpte)) != 0;
> -out:
> +		return true;
>  
> -	return changed;
> +	return memcmp(pdpte, vcpu->arch.walk_mmu->pdptrs, sizeof(pdpte)) != 0;
>  }
>  EXPORT_SYMBOL_GPL(pdptrs_changed);
>  
>