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X-CSE-ConnectionGUID: XlCCHSAjTY6x933WoVNvWQ== X-CSE-MsgGUID: zSO7ygN6TK6i7HR4OpIqJQ== X-IronPort-AV: E=McAfee;i="6800,10657,11733"; a="85622694" X-IronPort-AV: E=Sophos;i="6.23,127,1770624000"; d="scan'208";a="85622694" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2026 10:58:27 -0700 X-CSE-ConnectionGUID: H7qQNEkOTcawIMEz4GAX1A== X-CSE-MsgGUID: wB4NVToBRk6WHSjRXdTTlg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,127,1770624000"; d="scan'208";a="227185086" Received: from rchatre-mobl4.amr.corp.intel.com (HELO [10.125.108.223]) ([10.125.108.223]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2026 10:58:27 -0700 Message-ID: <8012d986-0d1f-47a2-8892-2b2dcc1339db@intel.com> Date: Wed, 18 Mar 2026 10:58:26 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] x86/cpu: Add INVLPGB CPU feature flag to /proc/cpuinfo To: Yongting Lin , tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, pawan.kumar.gupta@linux.intel.com, xin@zytor.com, babu.moger@amd.com, riel@surriel.com Cc: linux-kernel@vger.kernel.org References: <20260318175204.21762-1-linyongting@bytedance.com> Content-Language: en-US From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/18/26 10:52, Yongting Lin wrote: > commit 767ae437a32d ("x86/mm: Add INVLPGB feature and Kconfig entry") > introduced support for the INVLPGB instruction as a fast TLB > invalidation mechanism. However, no corresponding CPU feature flag is > exposed via /proc/cpuinfo. The patch is probably OK, but the changelog is insufficient. Could you please read through: Documentation/arch/x86/cpuinfo.rst and use that structure to construct a justification for why this feature is needed? I'd also just appreciate a blurb on why you care. Why did you bother to send this patch?