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Date: Tue, 7 May 2024 22:19:53 -0700
From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	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>,
	Maksim Davydov <davydov-max@yandex-team.ru>
Subject: Re: [PATCH v5 3/3] x86/bugs: Add 'spectre_bhi=vmexit' cmdline option
Message-ID: <20240508051953.oz3q3hdvifo6lb7o@treble>
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 <ab3e92eb-d35e-4f5a-8e99-10b3ccb7c2cf@linux.intel.com>
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In-Reply-To: <ab3e92eb-d35e-4f5a-8e99-10b3ccb7c2cf@linux.intel.com>

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!

-- 
Josh