From: Borislav Petkov <bp@alien8.de>
To: Sean Christopherson <seanjc@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org,
Stephen Rothwell <sfr@canb.auug.org.au>,
Michael Ellerman <mpe@ellerman.id.au>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Will Deacon <will@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2 2/2] cpu: Ignore "mitigations" kernel parameter if CPU_MITIGATIONS=n
Date: Sat, 20 Apr 2024 15:36:30 +0200 [thread overview]
Message-ID: <20240420133630.GCZiPE3lZ3m-M1CqG_@fat_crate.local> (raw)
In-Reply-To: <20240420000556.2645001-3-seanjc@google.com>
On Fri, Apr 19, 2024 at 05:05:55PM -0700, Sean Christopherson wrote:
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 619a04d5c131..928820e61cb5 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2495,9 +2495,13 @@ menuconfig CPU_MITIGATIONS
> help
> Say Y here to enable options which enable mitigations for hardware
> vulnerabilities (usually related to speculative execution).
> + Mitigations can be disabled or restricted to SMT systems at runtime
> + via the "mitigations" kernel parameter.
>
> - If you say N, all mitigations will be disabled. You really
> - should know what you are doing to say so.
> + If you say N, all mitigations will be disabled. This CANNOT be
> + overridden at runtime.
You probably wanna highlight the fact here that saying N means it'll
simply not even build in the mitigations code, leading to the physical
inability :) to enable them later, at run time.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2024-04-20 13:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-20 0:05 [PATCH v2 0/2] cpu: Fix default mitigation behavior Sean Christopherson
2024-04-20 0:05 ` [PATCH v2 1/2] cpu: Re-enable CPU mitigations by default for !X86 architectures Sean Christopherson
2024-04-24 5:38 ` Josh Poimboeuf
2024-04-25 14:18 ` [tip: x86/urgent] " tip-bot2 for Sean Christopherson
2024-04-20 0:05 ` [PATCH v2 2/2] cpu: Ignore "mitigations" kernel parameter if CPU_MITIGATIONS=n Sean Christopherson
2024-04-20 13:36 ` Borislav Petkov [this message]
2024-04-24 5:39 ` Josh Poimboeuf
2024-04-24 13:42 ` Borislav Petkov
2024-04-24 15:48 ` Sean Christopherson
2024-04-25 14:18 ` [tip: x86/urgent] " tip-bot2 for Sean Christopherson
2024-04-20 13:33 ` [PATCH v2 0/2] cpu: Fix default mitigation behavior Borislav Petkov
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