Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <0c908258-2b03-ebb3-bc7d-af5ea66479d4@intel.com>
Date:   Wed, 21 Jun 2023 15:58:10 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.11.0
Subject: Re: [PATCH v2] x86/bugs: Break down mitigations configurations
Content-Language: en-US
To:     Breno Leitao <leitao@debian.org>
Cc:     Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@kernel.org>, leit@fb.com,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@vger.kernel.org>
References: <20230616164851.2559415-1-leitao@debian.org>
 <20230621001327.qdyebewnx7r5aiy3@desk> <ZJMdKUr98H8zPSAl@gmail.com>
 <20230621173135.wiprtgzslhw5z5or@desk> <ZJNDRSUZuZ2L+pwo@gmail.com>
 <20230621194101.bmwesljror2yqjxx@desk>
 <d9bc78ed-1f05-47db-e916-d4d8bc76634e@intel.com> <ZJN/SGwvOBZmChJw@gmail.com>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <ZJN/SGwvOBZmChJw@gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/21/23 15:52, Breno Leitao wrote:
> On Wed, Jun 21, 2023 at 03:35:45PM -0700, Dave Hansen wrote:
>> On 6/21/23 12:41, Pawan Gupta wrote:
>>> Yes, a single series (or a patch) that adds config for each mitigation
>>> would be good.
>> Do people _really_ want per-mitigation compile-time controls?  That
>> seems like kinda a pain.
>>
>> I Boris suggested it, but it seems like a _bit_ of overkill to me.
>>
>> Would a compile-time option that just defaulted _everything_ to
>> mitigations=off behavior work instead?  That way we don't end up with a
>> billion new config options.
> This is exactly what my original patch proposed. It solves the problem with
> a few lines of changes.
> 
> https://lore.kernel.org/lkml/20230203120615.1121272-1-leitao@debian.org/

Hey Boris,

I like this simple thingy better.  If for no other reason than it
reduces the burden of what we have to do for every _new_ mitigation
going forward.

Do you like the direction this is going?  Maybe I'm missing something.