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 6AC26190685; Mon, 29 Sep 2025 17:45:14 +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=1759167915; cv=none; b=M84/2V/3suTEKuQRdJ/Og1kOk9O/B0RLTRuHoJHGwr3ch86gUECC2DXeLsuWjhDhwiPrE6uVZ19abew++txOQB5RH4D5BMSX9DdsDeuK5UzlP96vOc9C2RGNp2FHF33RMYRrpGCPQAzSxrC4HAP31SV5l0IsIfqi2DQZnNLW/YA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759167915; c=relaxed/simple; bh=+G3B6ottzqC8PO6P98aEhsz/FPcrbqUJ7DeHE4Pt9V0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kb+X/VXrq6JhSBdZXp2XEo+jRtdw4O+cLCVcTwst+/GnwuDAKI3YGgq1s8acXi9yrOedXBRqqqdy3/Brd5wXR4EqKj+kxYzHqmvX1KypXUjwtiZ7/Ohgc6IDHLGm5Qp2nRQgImJNM3W5dW6VbffCibrHxUTotjhxJG78Yj1r48A= 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 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 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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