From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 30152335BC1; Wed, 27 Aug 2025 08:53:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756284835; cv=none; b=NJZlHVf2m8PjGOz2eIuEidUpXVC29n5Sl37XBobZ2tRTxZjQxRu2A6h2jgsS0Xjjz4V0xfl83OvwPsbH0CaitApkMmTinb65f0uT1lBrm6po25W4wGF3WpANsoMckSuIWc8Og1lk3AK8D+LZDJ1URqJinfyw9fPPOQRiwvtzfwk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756284835; c=relaxed/simple; bh=P38O43fMuBeGBKDmS2PF3LrHlp668kFtyl36Iw5bUrI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=i+SHBp7lNJ4IpIioW0KsbY6irCArybLIue7jpoOirirbjByJ/92PKxptRPBXNP0RHM8MYCukPcbF9vwBKgVUTTwpBmGNTQmtwb61sRu+EUhkpt+yQwMVvyybJp+G7DF+RHMesV56yO2F9Yktq4PufpSxcYHqzrlDLCMlDqulPB0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 159921655; Wed, 27 Aug 2025 01:53:44 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3EE013F738; Wed, 27 Aug 2025 01:53:47 -0700 (PDT) Message-ID: <0c8a6a7c-3d0d-4093-8bc5-3a04f70b00fa@arm.com> Date: Wed, 27 Aug 2025 09:53:45 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/33] arm64: kconfig: Add Kconfig entry for MPAM To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org Cc: shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250822153048.2287-1-james.morse@arm.com> <20250822153048.2287-8-james.morse@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <20250822153048.2287-8-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi James, On 8/22/25 16:29, James Morse wrote: > The bulk of the MPAM driver lives outside the arch code because it > largely manages MMIO devices that generate interrupts. The driver > needs a Kconfig symbol to enable it, as MPAM is only found on arm64 > platforms, that is where the Kconfig option makes the most sense. > > This Kconfig option will later be used by the arch code to enable > or disable the MPAM context-switch code, and registering the CPUs > properties with the MPAM driver. > > Signed-off-by: James Morse > Reviewed-by: Jonathan Cameron > --- > arch/arm64/Kconfig | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e9bbfacc35a6..658e47fc0c5a 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -2060,6 +2060,23 @@ config ARM64_TLB_RANGE > ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a > range of input addresses. > > +config ARM64_MPAM > + bool "Enable support for MPAM" > + help > + Memory Partitioning and Monitoring is an optional extension > + that allows the CPUs to mark load and store transactions with > + labels for partition-id and performance-monitoring-group. > + System components, such as the caches, can use the partition-id > + to apply a performance policy. MPAM monitors can use the > + partition-id and performance-monitoring-group to measure the > + cache occupancy or data throughput. > + > + Use of this extension requires CPU support, support in the > + memory system components (MSC), and a description from firmware > + of where the MSC are in the address space. > + > + MPAM is exposed to user-space via the resctrl pseudo filesystem. > + > endmenu # "ARMv8.4 architectural features" Should this be moved to "ARMv8.2 architectural features" rather than the 8.4 menu? In the arm reference manual, version L.b, I see FEAT_MPAM listed in the section A2.2.3.1 Features added to the Armv8.2 extension in later releases. > > menu "ARMv8.5 architectural features" Thanks, Ben