linux-kernel - Re: [PATCH 5/8] KVM: SVM: fix comment

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Message-ID: <9e1504dc-514c-8bbd-f941-f1edca5e8f50@redhat.com>
Date:   Mon, 15 Jan 2018 10:53:22 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     rkrcmar@...hat.com, liran.alon@...cle.com, jmattson@...gle.com,
        aliguori@...zon.com, thomas.lendacky@....com, dwmw@...zon.co.uk,
        bp@...en8.de, x86@...nel.org
Subject: Re: [PATCH 5/8] KVM: SVM: fix comment

On 09.01.2018 13:03, Paolo Bonzini wrote:
> If always==true, then read/write bits are cleared from
> the MSR permission bitmap, thus passing-through the MSR.
> Fix the comment to match reality.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  arch/x86/kvm/svm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 55dde3896898..31ace8d7774a 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -236,7 +236,7 @@ struct amd_svm_iommu_ir {
>  
>  static const struct svm_direct_access_msrs {
>  	u32 index;   /* Index of the MSR */
> -	bool always; /* True if intercept is always on */
> +	bool always; /* True if intercept is always off */
>  } direct_access_msrs[] = {
>  	{ .index = MSR_STAR,				.always = true  },
>  	{ .index = MSR_IA32_SYSENTER_CS,		.always = true  },
> 

The function set_msr_interception() is really named confusingly.

If we pass in a "1", we clear the bit, resulting in no interception.

So 1==no intercept, 0==intercept. This function would be better named
"disable_msr_interception" or sth. like that.

Reviewed-by: David Hildenbrand <david@...hat.com>

-- 

Thanks,

David / dhildenb