From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5ACC0CAC5B9 for ; Mon, 29 Sep 2025 17:45:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=j4em2lZOOBEUhKYvANMjmIesb63X37XcCy+DllgJDHI=; b=WYs/bXqCbpj1HsGoom8UWTldaW Twxwft10+8DuTo8GxwT9JjcJjmsdj+INCzdSyp8lRQIsZkMfxGuD6vM+T1GgzNedjBrMnwKgeHpSA C+nQwY3JM0cZdloxPwOxgnhjau9NKvQPiaM1T7itONrPTapCOk9QEBU5zzxpEVgN+NSTR0XzD300E mm8bGp+NMFkRzkirCbQc7tEn6xmSBrcpuli7zLlGLz7/cnrMNLz5aI2v1mJKUafjMZV1KqeBx0Wa3 0YvQYBs8B69LnIze301xLHDRFIspj1uehAne5LqlfywJQ3DN3jcctctgBcc6dMERUNBe5F+4TXtKD R3GQph9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v3HwV-00000003ARL-1eiv; Mon, 29 Sep 2025 17:45:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v3Hw2-00000003AAt-26Jm for linux-arm-kernel@lists.infradead.org; Mon, 29 Sep 2025 17:45:16 +0000 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 DF6081CC4; Mon, 29 Sep 2025 10:45:05 -0700 (PDT) Received: from [10.1.197.69] (eglon.cambridge.arm.com [10.1.197.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6BFDE3F59E; Mon, 29 Sep 2025 10:45:08 -0700 (PDT) Message-ID: <32bc0e4a-d0bb-4aaa-8706-95a6edd470a9@arm.com> Date: Mon, 29 Sep 2025 18:45:07 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 13/29] arm_mpam: Probe the hardware features resctrl supports To: Ben Horgan , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: 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 , 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 , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250910204309.20751-1-james.morse@arm.com> <20250910204309.20751-14-james.morse@arm.com> <8ed9fbe9-1075-4abb-91d0-20203906a4dc@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: <8ed9fbe9-1075-4abb-91d0-20203906a4dc@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250929_104514_697684_1D9E831B X-CRM114-Status: GOOD ( 18.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Ben, On 11/09/2025 16:37, Ben Horgan wrote: > On 9/10/25 21:42, James Morse wrote: >> Expand the probing support with the control and monitor types >> we can use with resctrl. >> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h >> index 4cc44d4e21c4..5ae5d4eee8ec 100644 >> --- a/drivers/resctrl/mpam_internal.h >> +++ b/drivers/resctrl/mpam_internal.h >> @@ -112,6 +112,55 @@ static inline void mpam_mon_sel_lock_init(struct mpam_msc *msc) >> raw_spin_lock_init(&msc->_mon_sel_lock); >> } >> >> +/* >> + * When we compact the supported features, we don't care what they are. >> + * Storing them as a bitmap makes life easy. >> + */ >> +typedef u16 mpam_features_t; >> + >> +/* Bits for mpam_features_t */ >> +enum mpam_device_features { >> + mpam_feat_ccap_part = 0, >> + mpam_feat_cpor_part, >> + mpam_feat_mbw_part, >> + mpam_feat_mbw_min, >> + mpam_feat_mbw_max, >> + mpam_feat_mbw_prop, >> + mpam_feat_msmon, >> + mpam_feat_msmon_csu, >> + mpam_feat_msmon_csu_capture, >> + mpam_feat_msmon_csu_hw_nrdy, >> + mpam_feat_msmon_mbwu, >> + mpam_feat_msmon_mbwu_capture, >> + mpam_feat_msmon_mbwu_rwbw, >> + mpam_feat_msmon_mbwu_hw_nrdy, >> + mpam_feat_msmon_capt, >> + MPAM_FEATURE_LAST, >> +}; > I added a garbled comment about this for v1. What I was trying to say is > that I don't think this quite matches what resctrl supports. For > instance, I don't think mpam_feat_ccap_part matches a resctrl feature. Ah - right. I thought you meant something was removed later. Looks like I thought something could be emulated with CCAP, but that turns out not to be true because it doesn't have an implicit isolation property, which the resctrl:bitmap-from-userspace requires. (I think rwbw was a later addition to the architecture and I added it to the wrong patch). I'll move that, _prop and _rwbw to the later patch. The split is fairly arbitrary - it was just somewhere to split an otherwise large patch, and does help determine if a bug is going to be visible to user-space or not. _capt can go completely. Last I heard no-one was interested in firmware descriptions of how the capture hardware can be triggered. I suspect no-one has done anything with it. Thanks, James