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Subject: Re: [PATCH v19 06/25] x86/cet: Add control-protection fault handler
To:     Borislav Petkov <bp@alien8.de>
Cc:     x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
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        Arnd Bergmann <arnd@arndb.de>,
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        Dave Hansen <dave.hansen@linux.intel.com>,
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        Weijiang Yang <weijiang.yang@intel.com>,
        Pengfei Xu <pengfei.xu@intel.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>
References: <20210203225547.32221-1-yu-cheng.yu@intel.com>
 <20210203225547.32221-7-yu-cheng.yu@intel.com>
 <20210205135927.GH17488@zn.tnic>
 <2d829cba-784e-635a-e0c5-a7b334fa9b40@intel.com>
 <20210208182009.GE18227@zn.tnic>
From:   "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Message-ID: <690bc3b9-2890-e68d-5e4b-cda5c21b496b@intel.com>
Date:   Mon, 8 Feb 2021 10:50:07 -0800
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On 2/8/2021 10:20 AM, Borislav Petkov wrote:
> On Fri, Feb 05, 2021 at 10:00:21AM -0800, Yu, Yu-cheng wrote:
>> The ratelimit here is only for #CP, and its rate is not counted together
>> with other types of faults.  If a task gets here, it will exit.  The only
>> condition the ratelimit will trigger is when multiple tasks hit #CP at once,
>> which is unlikely.  Are you suggesting that we do not need the ratelimit
>> here?
> 
> I'm trying to first find out why is it there.
> 
> Is this something you've hit during testing and thought, oh well, this
> needs a ratelimit or was it added just because?
> 

I have not run into the situation.  Initially it was there because other 
faults have it.  When you asked, I went through it and put out my 
reasoning.  I think it still makes sense to keep it.

--
Yu-cheng