From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CEFE6320CAC for ; Mon, 5 Jan 2026 17:08:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767632939; cv=none; b=skRT9Vl60Wj+kEZTF11Za0epcx7R5ab027DeTX4lnoWHyt5J58eAVQKn9gzyZDiGdvtIIWafuFEy8PlDV3LsepkZwdyob+hC90+QTbxgCegbOfCWyKjJFxnpYJGGTygHsg9Meq1DqSPjTOnonOziR9pbdJOlHx3cgKMLZtZeoSI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767632939; c=relaxed/simple; bh=IZsI07CxVhpNxgQ4DW+ExIJpg876Gb3cyG/OGjDJ9Rg=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UeixPu3eC+Oij4eo1AlChIr4GgEwsPGoD57f+fXh57mKyAhDKKEwYJIWbfzrBh4RxTvVUDjSwTcQETpCSWBl9osZHJ+GPRNASJEuJI5WqO0OF/CiCu4xo8mOtG9ctaLPoiNZc4qoCQW2sYP5fyjNwhvIuCQBH5cWyGAwTJ25kWo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dlLNy3fzgzHnGgr; Tue, 6 Jan 2026 01:08:50 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 15DB140565; Tue, 6 Jan 2026 01:08:53 +0800 (CST) Received: from localhost (10.126.174.38) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Mon, 5 Jan 2026 17:08:51 +0000 Date: Mon, 5 Jan 2026 17:08:50 +0000 From: Jonathan Cameron To: Ben Horgan CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v2 09/45] arm64: mpam: Advertise the CPUs MPAM limits to the driver Message-ID: <20260105170850.000075b5@huawei.com> In-Reply-To: <20251219181147.3404071-10-ben.horgan@arm.com> References: <20251219181147.3404071-1-ben.horgan@arm.com> <20251219181147.3404071-10-ben.horgan@arm.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500012.china.huawei.com (7.191.174.4) To dubpeml100005.china.huawei.com (7.214.146.113) On Fri, 19 Dec 2025 18:11:11 +0000 Ben Horgan wrote: > From: James Morse > > Requestors need to populate the MPAM fields for any traffic they send on > the interconnect. For the CPUs these values are taken from the > corresponding MPAMy_ELx register. Each requestor may have a limit on the > largest PARTID or PMG value that can be used. The MPAM driver has to > determine the system-wide minimum supported PARTID and PMG values. > > To do this, the driver needs to be told what each requestor's limit is. > > CPUs are special, but this infrastructure is also needed for the SMMU and > GIC ITS. Call the helper to tell the MPAM driver what the CPUs can do. > > The return value can be ignored by the arch code as it runs well before the > MPAM driver starts probing. > > Signed-off-by: James Morse > Signed-off-by: Ben Horgan Reviewed-by: Jonathan Cameron