From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 42911313527 for ; Mon, 8 Jun 2026 08:33:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780907613; cv=none; b=LVYoCfzuMdVSqq4OKewqs/z14uCeEIn1AbU99bTRqRBhj13hkS9XcBF1SB4PdldGyowaq21ZR5fyfjZOkFh3sMdEz39WxbyEJ+hKxhie7JsSzFEH6dQ2NN5WhxPA6URxJEhDPDsUsyfOfbFDa+IcyF6/sDY0aKwlUqSonrlYCYA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780907613; c=relaxed/simple; bh=wGwQsNj5i2rU/gEGVnilE4gMylNXiCk+8VCfNuWJ7Ak=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ciQqSTxfIwXW2jH7swyPlFKWtEaIRK3dqHnw0+l0FDfEYudaFDgADAoVBcMZ+dRuOQuetxmI4qTvhjT5GRUHKmA7w5JyjtKO1s7VQrqcf80WSNN3h7BIh+9inWrpg7EkH9c31mfknQfWLCR9xfZDEqpIP1Hk9JMXs5hkQNAP/hI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GPX3nuQ/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GPX3nuQ/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A8561F00893; Mon, 8 Jun 2026 08:33:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780907612; bh=wGwQsNj5i2rU/gEGVnilE4gMylNXiCk+8VCfNuWJ7Ak=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=GPX3nuQ/E774VR8w1rNJrbG7V18bX2yDh1lGWysyVB3oDXwHRuZfbxDZYBqNtuF2F TNqUwRRNMC/oijrQhC/xttl/P9jxzskangY8HiXz8tz29nYv6SZIHXSwKu/w43+3FF YA76YZnMRyavx+lD/ZYhCo132iE5TwaP2NfrLpis8X8jEYvzTK6Xt1V2x/G3GuDViQ kZmStB6hdXOGUoIgwYqYKT1N3JAeBVbzD7gkMoq/bWdu8PAD4fp39KNrSZ1jq99aIu sJMaTRPP3WoM3S/9SwEVxLt5GCHQZFkUi+kmew5/eFMjjgfSo3xanJEcUsklw6Llho TvZNp2pk9n3rQ== From: Thomas Gleixner To: Chen Yu , tony.luck@intel.com, reinette.chatre@intel.com Cc: x86@kernel.org, linux-kernel@vger.kernel.org, bp@alien8.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, dave.martin@arm.com, james.morse@arm.com, fenghuay@nvidia.com, babu.moger@amd.com, anil.keshavamurthy@broadcom.com Subject: Re: [PATCH v3 6/6] x86/resctrl: Add support for L3 occupancy monitoring via RMID MMIO read In-Reply-To: <8d3ae8b7f66f4ed2765cbe9c18d1d831ed28b894.1780710620.git.yu.c.chen@intel.com> References: <8d3ae8b7f66f4ed2765cbe9c18d1d831ed28b894.1780710620.git.yu.c.chen@intel.com> Date: Mon, 08 Jun 2026 10:33:28 +0200 Message-ID: <87y0gp4ejr.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Sat, Jun 06 2026 at 10:38, Chen Yu wrote: > The CMRC (Cache Monitoring Registers for CPU Agents Description) > ACPI sub-table provides the MMIO address used to read the LLC > occupancy counter for each RMID. When ERDT is enabled on the > platform, use this MMIO interface instead of the legacy MSR read > to obtain the L3 occupancy value. > > Introduce erdt_mon_read(), a helper that retrieves monitoring > data for a given RMID and event ID from an ERDT domain. Initial > support is added for the L3 occupancy monitoring event > (QOS_L3_OCCUP_EVENT_ID). > > If the platform supports ERDT, CMRC-based MMIO access is used by > default. If ERDT is unavailable, the implementation is to use > MSR-based operations. > > Suggested-by: Tony Luck > Co-developed-by: Anil S Keshavamurthy > Signed-off-by: Anil S Keshavamurthy > Signed-off-by: Chen Yu Reviewed-by: Thomas Gleixner