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 106D841D65A; Tue, 28 Jul 2026 10:24:30 +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=1785234272; cv=none; b=rnUjg5wsJrogU/JHx6esuSQoStsOEOZ3OwL/yU0socaqjFojohy3j4tk++pZ0l45u9Uu2aetZ4rk/98S9L5Kq+Kol1jvYMuxJzIuQFjek952E93Ra3qncGpSllZHqZHQqCIjw0h+8AUqYmF/grjuEy/K4Hqvi3I6y0D7f5Yb+3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785234272; c=relaxed/simple; bh=Qmp+S4jeEmSrfkFAfQ5zyR7lzd8T38ptAobQNxd/cuU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Gh0wKSODcnLrBwiLEVkEus3XgsZa9lrVwkXGcakePts+cD51gDYmIIkomr/S/tQKHDb1cYZKcpy99HY5o/qE4/QqJ2ZaFJZ22Sh0VkrWXDT7LUIdZRUInj0iwJ6BKRlRdsEGXhV7f4XKgLrUM+voFgLtMM1LpX51upS9Ort8A1M= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=SJoNAdeg; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="SJoNAdeg" 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 0DE7D1A9A; Tue, 28 Jul 2026 03:24:26 -0700 (PDT) Received: from [192.168.178.24] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 88F8A3F66F; Tue, 28 Jul 2026 03:24:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785234270; bh=Qmp+S4jeEmSrfkFAfQ5zyR7lzd8T38ptAobQNxd/cuU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SJoNAdegQ7YKgun3wquk6jCn/mdv9DajGXn+1hdsfPdT+pcXBg9qEg2yzQ6VpNyta yRKeNFrrELThJLda9OTQ2THOOTS49n5hTEam30QxUHBoHnctkdaAXmieiaC4TgUmV7 XmLOIkBrKGhWFoiXy/YoqSi8OyRf3fcUqsNrb8FY= Message-ID: <22434d15-7e7c-457d-8431-b77db9448cf0@arm.com> Date: Tue, 28 Jul 2026 12:24:25 +0200 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 v4 08/10] arm_mpam: add MPAM-Fb MSC firmware access support To: Ritwick Sharma Cc: ben.horgan@arm.com, catalin.marinas@arm.com, fenghuay@nvidia.com, ganapatrao.kulkarni@oss.qualcomm.com, guohanjun@huawei.com, james.morse@arm.com, jic23@kernel.org, lee@trager.us, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, rafael@kernel.org, reinette.chatre@intel.com, sramana@qti.qualcomm.com, srivathsa.rao@oss.qualcomm.com, sudeep.holla@kernel.org, tsoni@quicinc.com, will@kernel.org References: <20260723155454.1760823-9-andre.przywara@arm.com> <20260728100421.4047928-1-ritwick.sharma@arm.com> Content-Language: en-GB From: Andre Przywara In-Reply-To: <20260728100421.4047928-1-ritwick.sharma@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Ritwick, On 7/28/26 12:04, Ritwick Sharma wrote: > On Thu, Jul 23, 2026 at 05:54:52PM +0200, Andre Przywara wrote: > >> - WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); >> + if (msc->iface == MPAM_IFACE_MMIO) >> + WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); > > I tested the MPAM-Fb series on an Arm AGI CPU. Many thanks for that, and for reporting on the list! > I think a similar MPAM_IFACE_MMIO check is needed in > mpam_msc_zero_mbwu_l(). Without this check, the mapped_hwpage_sz bounds > check is also performed for an MPAM-Fb MSC, which does not have an MMIO > mapping. I observed the following warning during testing: > > [ 50.638246] WARNING: drivers/resctrl/mpam_devices.c:1266 at mpam_msc_zero_mbwu_l+0x98/0xa8 Ouch, you are right, I missed that one. It seems my very limited testing didn't touch that code path. > There also appears to be an off-by-one issue in the calculation of > mapped_hwpage_sz: > > msc->mapped_hwpage_sz = msc_res->end - msc_res->start; > > The current calculation records a size that is one byte smaller than > the actual resource. I think this should use resource_size() instead: > > msc->mapped_hwpage_sz = resource_size(msc_res); Well spotted, I can make a separate patch for that, unless you beat me to it! Many thanks, Andre > > Thanks, > Ritwick