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 E86BB1E7C18; Fri, 14 Nov 2025 14:34:41 +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=1763130884; cv=none; b=mQ5i4j+tMZ1TcW6SQaf7sE0dHezwt7v4FNkCVMK8y8EAIAcMmjCiFzO0FDZRHhe1jh/fqNh9C1rz8fsLEni1kDzr9rvsrX25gJDoYsXTWNMLXNNSNB0HNUHdlI0Ras16UEfIiY5Nn8ynmL0nIZCtqFvyjAQDlxPLkAfw6AR3sCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763130884; c=relaxed/simple; bh=C6xej7gbgx9rWFTnu4qMbIdd5TzFRa0VFArmEkUk5MQ=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=obKlKggT3+O29z1L9Lz+Dv8e+WNNTr4UBKNtmf6av0iWeJtKOv5eWUGgnxnL9Ljy6RQ0w5HkRuZvDulYptTN4Tw8KQi2VqYHx8PqFHAqVQVkHt5q0wjfj4t2NkDI9sLLEy2PnEzR+iBlJP1qRlmQt+0dJsr+/qk6l719F9PozDw= 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 2E79A1063; Fri, 14 Nov 2025 06:34:33 -0800 (PST) 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 3EE873F5A1; Fri, 14 Nov 2025 06:34:36 -0800 (PST) Message-ID: Date: Fri, 14 Nov 2025 14:34:34 +0000 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 23/33] arm_mpam: Allow configuration to be applied and restored during cpu online From: Ben Horgan To: Jonathan Cameron Cc: james.morse@arm.com, amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com References: <20251107123450.664001-1-ben.horgan@arm.com> <20251107123450.664001-24-ben.horgan@arm.com> <20251110172724.00005675@huawei.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Jonathan, On 11/14/25 10:33, Ben Horgan wrote: > Hi Jonathan, > > On 11/10/25 17:27, Jonathan Cameron wrote: >> On Fri, 7 Nov 2025 12:34:40 +0000 >> Ben Horgan wrote: >> >>> From: James Morse >>> >>> When CPUs come online the MSC's original configuration should be restored. >>> >>> Add struct mpam_config to hold the configuration. This has a bitmap of >>> features that were modified. Once the maximum partid is known, allocate >> >> I'm not following 'were modified'. When? Sometime in the past? >> Perhaps "features that have been modified when XXX happens" or > > The intent of the features bitmp is to only update the configuration in > hardware for the feautures that require it. On reset, this is all > features, but for a user configuration change this is just the > difference from what was previously set. I wasn't quite correct here. The feature bitmap for each component indicates which features have been changed (by user configuration) to a value different from their default. These bits aren't unset when the setting is changed back to the reset value. It can thus be used on power restoration to restore the user config. I think this is what James meant by "were modified". > > However, I don't think the difference part is currently working > correctly; the bitmap always has all the bits set and so any update > configures everything. I'll look into this. > >> >> Having read the code I think this is something like "are modified as configuration >> is read". >> >>> a configuration array for each component, and reprogram each RIS >>> configuration from this. > Thanks, > > Ben > > -- Thanks, Ben