From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v4 2/4] KVM: Add SMAP support when setting CR4
Date: Thu, 10 Apr 2014 17:12:34 -0300
Message-ID: <20140410201234.GB26092@amt.cnet>
References: <1396345596-25682-1-git-send-email-feng.wu@intel.com>
 <1396345596-25682-3-git-send-email-feng.wu@intel.com>
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Cc: pbonzini@redhat.com, gleb@redhat.com, hpa@zytor.com,
	kvm@vger.kernel.org
To: Feng Wu <feng.wu@intel.com>
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On Tue, Apr 01, 2014 at 05:46:34PM +0800, Feng Wu wrote:
> This patch adds SMAP handling logic when setting CR4 for guests
> 
> Thanks a lot to Paolo Bonzini for his suggestion to use the branchless
> way to detect SMAP violation.
> 
> Signed-off-by: Feng Wu <feng.wu@intel.com>
>
> @@ -110,10 +118,30 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu)
>   * Will a fault with a given page-fault error code (pfec) cause a permission
>   * fault with the given access (in ACC_* format)?
>   */
> -static inline bool permission_fault(struct kvm_mmu *mmu, unsigned pte_access,
> -				    unsigned pfec)
> +static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> +				    unsigned pte_access, unsigned pfec)
>  {
> -	return (mmu->permissions[pfec >> 1] >> pte_access) & 1;
> +	int cpl = kvm_x86_ops->get_cpl(vcpu);
> +	unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);

Some branches added here (can't think of anything useful to avoid them).