From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from iguana.tulip.relay.mailchannels.net (iguana.tulip.relay.mailchannels.net [23.83.218.253]) (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 2497E2BDC1C for ; Wed, 9 Sep 2026 17:03:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=23.83.218.253 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788973425; cv=none; b=fFWSLX2QQsARParOPWoPWAIDgeL9a5Ix6cYlOrnuZyigLsY6stkDazw9I6vEGgOl2d5ZvbDQpPANC+2FjLubJJltyZEDeg37f70fWQ4VashflrVNKuJelQFBzWK1xG6IR91VJCrzIGq5qlPExqZALdsgicnA4/r3g8Y5Hpf789o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788973425; c=relaxed/simple; bh=cbCHvIX2gWmrlut41+2xo9VbpBiO4/ZO+kJpjQIn8rE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=qFdMU0fJ2SAs6zFp3oLZ80cDcj1BlCix9FWZ1vScywjn5lxuIqdhbjKKdavV+Xj240WLWUlgFQ6e2aF05BiUjMmFg2SM85OahJewWTxfnKs8sZIpVvgTQOnrDTCfaw7LTrB2Z3Nrrbp6nfn44MVAl4JO7Gc+T7UjC0vuISyr9Yc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.net; spf=fail smtp.mailfrom=stgolabs.net; dkim=pass (2048-bit key) header.d=stgolabs.net header.i=@stgolabs.net header.b=WuT4wrOs; arc=none smtp.client-ip=23.83.218.253 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.net Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=stgolabs.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=stgolabs.net header.i=@stgolabs.net header.b="WuT4wrOs" X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 4F3907E2622; Wed, 09 Sep 2026 17:03:35 +0000 (UTC) Received: from pdx1-sub0-mail-a213.dreamhost.com (100-96-170-102.trex-nlb.outbound.svc.cluster.local [100.96.170.102]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id 1D4497E0535; Wed, 09 Sep 2026 17:03:35 +0000 (UTC) X-Sender-Id: dreamhost|x-authsender|dave@stgolabs.net X-MC-Relay: Neutral X-MailChannels-SenderId: dreamhost|x-authsender|dave@stgolabs.net X-MailChannels-Auth-Id: dreamhost X-Cooperative-Continue: 661a372779c28011_1788973415211_1431491025 X-MC-Loop-Signature: 1788973415211:581800596 X-MC-Ingress-Time: 1788973415211 Received: from pdx1-sub0-mail-a213.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384) by 100.96.170.102 (trex/8.0.2); Wed, 09 Sep 2026 17:03:35 +0000 Received: from offworld.lan (unknown [76.167.199.67]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dave@stgolabs.net) by pdx1-sub0-mail-a213.dreamhost.com (Postfix) with ESMTPSA id 4hg6Zt3d58z1Z; Wed, 9 Sep 2026 10:03:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stgolabs.net; s=dreamhost; t=1788973414; bh=cadbRqPnF+sII9/gFs+xvmqDlNZ+McQEEYaOl/Gbpug=; h=From:To:Cc:Subject:Date:Content-Transfer-Encoding; b=WuT4wrOst2VSPj64kc0YnpHjkXDKwyEjggATv4YL6k99MeUy+S8FbqIljrN1psYqH AGJRuWSa1HN6vDhm8RFLdGOz9sJXfucC9FLuA/tU3VbSEhw4NW4CNDK1m4RvDS9RoB VU8hmnzxsoQc9Q5hDD8yp0KHOHTI7N3cp85PPRcO4SwJjJj3ytWi/Z4AY9tE0cBy6t GhJjmyWjToaTqh7AcgjbeuvUoQ9TEb8Zh+ZQ6P9IKvKiUZJbK48cSZqAC1mmOClG45 n6bD8b/S4lNZOX+guiq5ysqzMgSpyftTVE8UlV+d7FexsMdz1pyrmzrlUSYC+6gwE2 lpelduYki3lIQ== From: Davidlohr Bueso To: dave.jiang@intel.com Cc: jic23@kernel.org, alison.schofield@intel.com, icheng@nvidia.com, ming.li@zohomail.com, benjamin.cheatham@amd.com, alucerop@amd.com, dave@stgolabs.net, linux-cxl@vger.kernel.org Subject: [PATCH v8 10/10] cxl/doc: Update maturity map with BI support Date: Wed, 9 Sep 2026 10:03:02 -0700 Message-Id: <20260909170302.1550680-11-dave@stgolabs.net> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260909170302.1550680-1-dave@stgolabs.net> References: <20260909170302.1550680-1-dave@stgolabs.net> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add the respective Back-Invalidate info to the maturity map document. Signed-off-by: Davidlohr Bueso --- Documentation/driver-api/cxl/maturity-map.rst | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/Documentation/driver-api/cxl/maturity-map.rst b/Documentation/driver-api/cxl/maturity-map.rst index 282c1102dd81..878fd8723685 100644 --- a/Documentation/driver-api/cxl/maturity-map.rst +++ b/Documentation/driver-api/cxl/maturity-map.rst @@ -63,6 +63,12 @@ in place, but there are several corner cases that are pending closure. * [0] Decoder target and granularity constraints +* [1] :ref:`Back-Invalidate (HDM-DB) ` + + * [3] BI topology enable / disable (endpoint, DSP, USP route table, RP) + * [2] Firmware-enabled path adoption + * [0] MLD / PBR switches (BI-ID carrying an LD-ID) + * [2] Performance enumeration * [3] Endpoint CDAT @@ -166,7 +172,7 @@ Accelerator ----------- * [0] Accelerator memory enumeration HDM-D (CXL 1.1/2.0 Type-2) -* [0] Accelerator memory enumeration HDM-DB (CXL 3.0 Type-2) +* [1] Accelerator memory enumeration HDM-DB (CXL 3.0 Type-2) * [0] CXL.cache 68b (CXL 2.0) * [0] CXL.cache 256b Cache IDs (CXL 3.0) @@ -192,6 +198,15 @@ Details hiding some standard registers like PCIe Link Status / Capabilities in the CXL RCRB (Root Complex Register Block). +.. _back-invalidate: + +* **Back-Invalidate**: HDM-DB lets a device snoop the host over the + CXL.mem BISnp channel instead of CXL.cache. The kernel enables BI on + every port between a device and its root port, requires 256B Flit + mode on the path, adopts paths firmware already enabled, and creates + HDM-DB regions under CFMWS windows carrying the Back-Invalidate + restriction for Type 3 and Type 2 devices alike. + .. _background-commands: * **Background commands**: The CXL background command mechanism is -- 2.39.5