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Message-ID: <22da39f0-e73f-4e11-830e-914b5bc04029@yandex-team.ru>
Date: Mon, 27 May 2024 13:45:59 +0300
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Subject: Re: [PATCH v5 3/3] x86/bugs: Add 'spectre_bhi=vmexit' cmdline option
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
 Daniel Sneddon <daniel.sneddon@linux.intel.com>,
 Linus Torvalds <torvalds@linux-foundation.org>,
 Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
 Thomas Gleixner <tglx@linutronix.de>,
 Alexandre Chartre <alexandre.chartre@oracle.com>,
 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
 Peter Zijlstra <peterz@infradead.org>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 Sean Christopherson <seanjc@google.com>,
 Andrew Cooper <andrew.cooper3@citrix.com>,
 Dave Hansen <dave.hansen@linux.intel.com>,
 Nikolay Borisov <nik.borisov@suse.com>, KP Singh <kpsingh@kernel.org>,
 Waiman Long <longman@redhat.com>, Borislav Petkov <bp@alien8.de>,
 Ingo Molnar <mingo@kernel.org>
References: <cover.1715059256.git.jpoimboe@kernel.org>
 <66327dcf87284a09ed17ac24227695ea3ba1f287.1715059256.git.jpoimboe@kernel.org>
 <ab3e92eb-d35e-4f5a-8e99-10b3ccb7c2cf@linux.intel.com>
 <20240508051953.oz3q3hdvifo6lb7o@treble>
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From: Maksim Davydov <davydov-max@yandex-team.ru>
In-Reply-To: <20240508051953.oz3q3hdvifo6lb7o@treble>
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On 5/8/24 08:19, Josh Poimboeuf wrote:
> On Tue, May 07, 2024 at 07:58:07AM -0700, Daniel Sneddon wrote:
>> On 5/6/24 22:30, Josh Poimboeuf wrote:
>>> In cloud environments it can be useful to *only* enable the vmexit
>>> mitigation and leave syscalls vulnerable.  Add that as an option.
>>>
>>> This is similar to the old spectre_bhi=auto option which was removed
>>> with the following commit:
>>>
>>>    36d4fe147c87 ("x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto")
>>>
>>> with the main difference being that this has a more descriptive name and
>>> is disabled by default.
>>>
>>> Requested-by: Maksim Davydov <davydov-max@yandex-team.ru>
>>> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
>>> ---
>>
>> Does the KConfig option need to be updated to support this as well?
> 
> In general we don't provide a config option for every possible
> mitigation cmdline option.  If someone requests it we could add it
> later.
> 
>> Reviewed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
> 
> Thanks!
> 

I think it will be useful for us to have appropriate Kconfig option. 
Could you please add it to the next version?

-- 
Best regards,
Maksim Davydov