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 89A4433985A; Tue, 3 Feb 2026 21:44:00 +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=1770155042; cv=none; b=ooRmz0UvH8sh5g6kumhwfuP/9KyWuZaALMuv9lGCnQB2+QnvFqCZoD7oOA8dW+vcfa33KsCCnTKLAGrNDhN4XbFCmc/ujSFuZ4gIZR1hCJ8E3r+cgDl2ss31ZfRJY/U7Yn4daIvU1vgyQ+2Qys4ldFCXk/yu0em+XiLyNDhFWXk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770155042; c=relaxed/simple; bh=IrlwYeHQ3xHoC7VqKOltKKXxSjdX0Gjv4EnX8UPmeoY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=WQjRaCFtamRwYLyjfbhMkAWMjXTupJzqBDOHtA9OCpWU9Zb9p6aw0xec1BgXZuwiieQLu8qDRz2itDWX5caPNt4ze4C/o4Pa679EvDoaJd/JGRRazozjBz8eKjL0gRNd+L/vEwQuKx5oWJHOS5k5DmrsA1eaNDJ55uQJXkuRM5s= 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 139BB339; Tue, 3 Feb 2026 13:43:53 -0800 (PST) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 086BA3F778; Tue, 3 Feb 2026 13:43:53 -0800 (PST) From: Ben Horgan To: ben.horgan@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, carl@os.amperecomputing.com, dave.martin@arm.com, david@kernel.org, dfustini@baylibre.com, fenghuay@nvidia.com, gshan@redhat.com, james.morse@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, peternewman@google.com, punit.agrawal@oss.qualcomm.com, quic_jiles@quicinc.com, reinette.chatre@intel.com, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, tan.shaopeng@fujitsu.com, xhao@linux.alibaba.com, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, kvmarm@lists.linux.dev, zengheng4@huawei.com, linux-doc@vger.kernel.org Subject: [PATCH v4 00/41] arm_mpam: Add KVM/arm64 and resctrl glue code Date: Tue, 3 Feb 2026 21:43:01 +0000 Message-ID: <20260203214342.584712-1-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This new version of the mpam missing pieces series has a few significant changes in the mpam driver part of the series. The heuristics for deciding if features should be exposed are tightened. This is to fix some inaccuracies and avoid overcommitting before needed - shout if this changes anything on your platform. The final patch adds documentation which explains which features you should expect. The ABMC emulation is dropped for the moment as it requires resctrl changes to support for MPAM without breaking the abi. The default 5% gap for min_bw is dropped in favour of a simple default (kept for grace). The series is based on x86/resctrl [1] as resctrl has telemetry patches queued which change the arch interface. Fixes that are in 6.19-rc8 are dropped from the series but b9f5c38e4af1 ("arm_mpam: Use non-atomic bitops when modifying feature bitmap") is required to avoid an alignment fault in the kunit tests. Thank you for all the testing and reviewing so far! It all helps. Changelogs in patches >From James' cover letter: This is the missing piece to make MPAM usable resctrl in user-space. This has shed its debugfs code and the read/write 'event configuration' for the monitors to make the series smaller. This adds the arch code and KVM support first. I anticipate the whole thing going via arm64, but if goes via tip instead, the an immutable branch with those patches should be easy to do. Generally the resctrl glue code works by picking what MPAM features it can expose from the MPAM drive, then configuring the structs that back the resctrl helpers. If your platform is sufficiently Xeon shaped, you should be able to get L2/L3 CPOR bitmaps exposed via resctrl. CSU counters work if they are on/after the L3. MBWU counters are considerably more hairy, and depend on hueristics around the topology, and a bunch of stuff trying to emulate ABMC. If it didn't pick what you wanted it to, please share the debug messages produced when enabling dynamic debug and booting with: | dyndbg="file mpam_resctrl.c +pl" I've not found a platform that can test all the behaviours around the monitors, so this is where I'd expect the most bugs. The MPAM spec that describes all the system and MMIO registers can be found here: https://developer.arm.com/documentation/ddi0598/db/?lang=en (Ignored the 'RETIRED' warning - that is just arm moving the documentation around. This document has the best overview) Based on: [1] git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/cache (To include telemetry code which changes the resctrl arch interface) The series can be retrieved from: https://gitlab.arm.com/linux-arm/linux-bh.git mpam_resctrl_glue_v4 (Final commit is a fix already in 6.19-rc8) v3 can be found at: https://lore.kernel.org/linux-arm-kernel/20260112165914.4086692-1-ben.horgan@arm.com/ v2 can be found at: https://lore.kernel.org/linux-arm-kernel/20251219181147.3404071-1-ben.horgan@arm.com/ rfc can be found at: https://lore.kernel.org/linux-arm-kernel/20251205215901.17772-1-james.morse@arm.com/ Ben Horgan (10): arm64/sysreg: Add MPAMSM_EL1 register KVM: arm64: Preserve host MPAM configuration when changing traps KVM: arm64: Make MPAMSM_EL1 accesses UNDEF arm64: mpam: Drop the CONFIG_EXPERT restriction arm64: mpam: Initialise and context switch the MPAMSM_EL1 register KVM: arm64: Use kernel-space partid configuration for hypercalls arm_mpam: resctrl: Add rmid index helpers arm_mpam: resctrl: Add kunit test for rmid idx conversions arm_mpam: resctrl: Wait for cacheinfo to be ready arm64: mpam: Add initial MPAM documentation Dave Martin (2): arm_mpam: resctrl: Convert to/from MPAMs fixed-point formats arm_mpam: resctrl: Add kunit test for control format conversions James Morse (25): arm64: mpam: Context switch the MPAM registers arm64: mpam: Re-initialise MPAM regs when CPU comes online arm64: mpam: Advertise the CPUs MPAM limits to the driver arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs arm64: mpam: Add helpers to change a task or cpu's MPAM PARTID/PMG values KVM: arm64: Force guest EL1 to use user-space's partid configuration arm_mpam: resctrl: Add boilerplate cpuhp and domain allocation arm_mpam: resctrl: Sort the order of the domain lists arm_mpam: resctrl: Pick the caches we will use as resctrl resources arm_mpam: resctrl: Implement resctrl_arch_reset_all_ctrls() arm_mpam: resctrl: Add resctrl_arch_get_config() arm_mpam: resctrl: Implement helpers to update configuration arm_mpam: resctrl: Add plumbing against arm64 task and cpu hooks arm_mpam: resctrl: Add CDP emulation arm_mpam: resctrl: Add support for 'MB' resource arm_mpam: resctrl: Add support for csu counters arm_mpam: resctrl: Pick classes for use as mbm counters arm_mpam: resctrl: Pre-allocate free running monitors arm_mpam: resctrl: Allow resctrl to allocate monitors arm_mpam: resctrl: Add resctrl_arch_rmid_read() and resctrl_arch_reset_rmid() arm_mpam: resctrl: Update the rmid reallocation limit arm_mpam: resctrl: Add empty definitions for assorted resctrl functions arm64: mpam: Select ARCH_HAS_CPU_RESCTRL arm_mpam: resctrl: Call resctrl_init() on platforms that can support resctrl arm_mpam: Quirk CMN-650's CSU NRDY behaviour Shanker Donthineni (4): arm_mpam: Add quirk framework arm_mpam: Add workaround for T241-MPAM-1 arm_mpam: Add workaround for T241-MPAM-4 arm_mpam: Add workaround for T241-MPAM-6 Documentation/arch/arm64/index.rst | 1 + Documentation/arch/arm64/mpam.rst | 93 + Documentation/arch/arm64/silicon-errata.rst | 9 + arch/arm64/Kconfig | 6 +- arch/arm64/include/asm/el2_setup.h | 3 +- arch/arm64/include/asm/mpam.h | 96 + arch/arm64/include/asm/resctrl.h | 2 + arch/arm64/include/asm/thread_info.h | 3 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/cpufeature.c | 21 +- arch/arm64/kernel/mpam.c | 62 + arch/arm64/kernel/process.c | 7 + arch/arm64/kvm/hyp/include/hyp/switch.h | 12 +- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 9 + arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 13 + arch/arm64/kvm/sys_regs.c | 2 + arch/arm64/tools/sysreg | 8 + drivers/resctrl/Kconfig | 9 +- drivers/resctrl/Makefile | 1 + drivers/resctrl/mpam_devices.c | 257 ++- drivers/resctrl/mpam_internal.h | 105 +- drivers/resctrl/mpam_resctrl.c | 1861 +++++++++++++++++++ drivers/resctrl/test_mpam_resctrl.c | 364 ++++ include/linux/arm_mpam.h | 32 + 24 files changed, 2949 insertions(+), 28 deletions(-) create mode 100644 Documentation/arch/arm64/mpam.rst create mode 100644 arch/arm64/include/asm/mpam.h create mode 100644 arch/arm64/include/asm/resctrl.h create mode 100644 arch/arm64/kernel/mpam.c create mode 100644 drivers/resctrl/mpam_resctrl.c create mode 100644 drivers/resctrl/test_mpam_resctrl.c -- 2.43.0