linux-kernel - Re: [PATCH 2/7] x86/bugs: Cache the value of MSR_IA32_ARCH

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Message-ID: <0503ff9b-afb7-43a5-b9eb-f6c9d9945638@suse.com>
Date: Thu, 11 Apr 2024 09:22:10 +0300
From: Nikolay Borisov <nik.borisov@...e.com>
To: Josh Poimboeuf <jpoimboe@...nel.org>, x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
 Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
 Thomas Gleixner <tglx@...utronix.de>,
 Alexandre Chartre <alexandre.chartre@...cle.com>,
 Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
 Peter Zijlstra <peterz@...radead.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Sean Christopherson <seanjc@...gle.com>,
 Andrew Cooper <andrew.cooper3@...rix.com>,
 Dave Hansen <dave.hansen@...ux.intel.com>, KP Singh <kpsingh@...nel.org>,
 Waiman Long <longman@...hat.com>, Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH 2/7] x86/bugs: Cache the value of
 MSR_IA32_ARCH_CAPABILITIES



On 11.04.24 г. 8:40 ч., Josh Poimboeuf wrote:
> There's no need to keep reading MSR_IA32_ARCH_CAPABILITIES over and
> over.  It's even read in the BHI sysfs function which is a big no-no.
> Just read it once and cache it.
> 
> Fixes: ec9404e40e8f ("x86/bhi: Add BHI mitigation knob")
> Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>


Reviewed-by: Nikolay Borisov <nik.borisov@...e.com>