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 0C297360EF0 for ; Thu, 1 Oct 2026 16:04:39 +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=1790870681; cv=none; b=S5Ks7cH+Q+gEXRSgL38URmO9Oq7KrXklHvZDqlbx1+IpC8oCcaJBbam0tCaifEppThB1Ot2FokzU+mx6v6sKsa6NN+JlzG8jqTRmKojf0o7kUy9tLQnQf2JNnb5tf/8ZLmV8F20l+05rFwa+jSYrxX+wQORMpFIJb70VOgcTzkU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790870681; c=relaxed/simple; bh=WqeZOyl9WYcfDPVmtE1Pp8XotgNarrmoX9goyjRjBe0=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=R4d6A+asinO3mZPE2CN6be72HL+C5EiPqMxM2sHwm5Kv7jpDmvJnyBItRLBVjNjU7Y0FSw70drahgt1RuUNAOcbB2/zDL58tl5EdcTfMLb4s/kQsfQrlvIxI2cX8D0dg88TU555fCoUeBZcdd/xDkawbnBS1m3C3KXvTNmmfBUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kZWRw98Z; 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="kZWRw98Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DD3E1F000FF; Thu, 1 Oct 2026 16:04:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790870679; bh=eRXHTzQFuxMpSqEsnQz/tMPtIw94RE1I1jU3SpB/T0E=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=kZWRw98ZDZUGRKXtg6e7zNKjtiVGZXbXLdbIwPS463cm3I7R48S5ZrH4lYmHVN5B0 9gM3GZWrUOlRxsAHUR7v6wksxAYZAmr9vji+aLvFSxH5ObPMu8X9JBg/hpiN5Ierpu jMY6f5LblsvWmbLM4JB7FQVQpUPp8kM4ZuquQLmbtFlFNNhuxGelxIizs6uQnpy1ui zriQyIOe6bN/2hk9u84K3HuNX5jOee8I/JrhB2xL4JFuzoDwwWYHoSGMgVGofZA02I KT6ydLOO1akbFKX0ZYXQIWn4ZNtt/rUl3ptJ4//a7Lfo5g/xyFgHrAXaaEPu/xFakQ Tx9S9js+ioRdw== From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 3/3] Expose the CPU/Steering Tag mapping via debugfs Reply-To: sashiko-reviews@lists.linux.dev To: "Wei Huang" Cc: linux-pci@vger.kernel.org In-Reply-To: <20261001155551.4182899-4-wei.huang2@amd.com> References: <20261001155551.4182899-1-wei.huang2@amd.com> <20261001155551.4182899-4-wei.huang2@amd.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 01 Oct 2026 16:04:38 +0000 Message-Id: <20261001160439.6DD3E1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Steering Tags (ST) are opaque, platform specific values obtained from the > ACPI ST _DSM, and are only visible to the driver that asks for them. That > makes it hard to validate whether firmware reports a sane mapping at all. >=20 > Expose the mapping read-only in the debugfs directory of each Root Port > that has ST _DSM support: >=20 > # cat /sys/kernel/debug/pci/0000:00:01.1/tph_cpu_st > cpu vm_st vm_xst vm_ph_ignore pm_st pm_xst pm_ph_ignore > 0 0x03 0x0103 0 - - 0 > 1 0x03 0x0103 0 - - 0 >=20 > Each line holds the raw ST info the _DSM returns for one online CPU; > invalid tags and failed queries are reported as "-". >=20 > The interface is per Root Port because the _DSM is evaluated on the ACPI > device of the host bridge above it. A system with multiple host bridges m= ay > return different tags for the same CPU, and the value that matters to a > driver is the one for the Root Port its device sits below. Root Ports bel= ow > the same host bridge report identical contents. >=20 > The file is created during enumeration and removed with the device's > debugfs directory in pci_destroy_dev(), which returns only once no read is > running, so the pci_dev the file refers to stays valid. >=20 > Signed-off-by: Wei Huang Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261001155551.4182= 899-1-wei.huang2@amd.com?part=3D3