From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH8PR06CU001.outbound.protection.outlook.com (mail-westus3azon11012057.outbound.protection.outlook.com [40.107.209.57]) (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 23A9F1FFC6D; Thu, 13 Nov 2025 20:05:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.209.57 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763064314; cv=fail; b=jBP+qHmAI3fJjU7SF9lY/c/g1AVHA8Ig8Bl/ZvMPJZGngzHUKKf2vA0ExawdKSjD7Q8kUUdb/TSgMVmC034l7E2S+CjODFIpMcuc4Xrf7P4pbU4V6GDDpeG0F4jhlQ7FLUAHPWlYysG4ouWzolAuJN0/otY3DonsthhA7ZMjgiw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763064314; c=relaxed/simple; bh=Cppl3/Q6M69fEFKHJz80//JgqarHF8gGn7Bzxmd4/b0=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=Rr12E8CShA84N+9h/O29AbIK3cmBxTFLsF/WTlnR3MzDLxQrIwb5T0EUFvox9NTrfOHmuYoiptrFUiSiYd3Mim+cNhXwAPCDucfkPXdpfRR7NXa0zYsu25ya++iZ3sLfitGkV3kXFTOdC1JGISLSRIh7zoBrtg4OlaR9s/tvPNc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=49IfgXJF; arc=fail smtp.client-ip=40.107.209.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="49IfgXJF" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=s2Q0ysZemNIagA5hJXpO3E/NBorD+Yj0udpvBO/42BuwBbQbVIyblOUesYrt7sDoLaNzG6MG3Ucqfy4U7uWTh0OyRmEmAtR9qiXtHkrv1YUDpTpVfRWEbNFXjaIR/HppRFOB9a4U03vUBcpvmvMgAV/Tc8BVrpOCIXNE/sZu1X++bsDnzKGsvi8th56950Jh/ptGYU07Df+A6j12EDQdQs5bErbA9GK4AEL3FRpCyJI/waVT4vR144Q2R33PG/P12y3U7yNPep+4KHKuJe9riPPGPfs7QoeaMq5ArYAdoXbN7twgneYdGezqT/uHvTRnHBfHHgN9KtDv1g8ExkZdgQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=GXhkDawDv1xRvXFBrDrDUHKaJn9a9fxurez8O1WI0d4=; b=A4HA/54aCYd3xDUdHy6hbdWqH7RsTLXNvUXd2GjQjtTIKkbbkAUS0U9Z6WZNs7I57ONpMisLtTmoAWgH0tBkUp9kbL1hGgKL27EDPM+LvS0anaBS5+ryQ20iObbVDTJqPDNXyLZKxspjclveI2SF2kmOBp3C+KXIpLCB1PC7Gwn4FmVA3IN3F2U4Yez+28d0N9XfPuFD88ENc2nkQoWPSH/cCVcLlhL0hbt3kiU3UhYSgcJgJCAyGqMznIK61DJZI5GMQS6gjHrF415avaGD4TcJUVXOiGOIsghB/lTYT7X4zxxLg5K2K/11zzAuhntrsXH8cBIIQOrxVEB1DmGBag== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=GXhkDawDv1xRvXFBrDrDUHKaJn9a9fxurez8O1WI0d4=; b=49IfgXJFop7Ybg19mJFtzEL3kAHTqqc7p5isIqXfIgQLa9QjhtIup9aTjxr14Sy5liKy6p5GC18rsU2i7em7z5Yj2HFSvki7PbnDCaZSPpIluGzimPouLhR1QJjvqWsS90ZWR++6Uj+dB6v5sP5Ab3VIzYy2iDRZhsd9W5+EZwU= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from CYYPR12MB8750.namprd12.prod.outlook.com (2603:10b6:930:be::18) by MN6PR12MB8469.namprd12.prod.outlook.com (2603:10b6:208:46e::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9298.16; Thu, 13 Nov 2025 20:05:10 +0000 Received: from CYYPR12MB8750.namprd12.prod.outlook.com ([fe80::b965:1501:b970:e60a]) by CYYPR12MB8750.namprd12.prod.outlook.com ([fe80::b965:1501:b970:e60a%5]) with mapi id 15.20.9320.013; Thu, 13 Nov 2025 20:05:10 +0000 Date: Thu, 13 Nov 2025 21:05:37 +0100 From: Robert Richter To: Dave Jiang Cc: Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Jonathan Cameron , Davidlohr Bueso , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, Gregory Price , "Fabio M. De Francesco" , Terry Bowman , Joshua Hahn Subject: Re: [PATCH v4 11/14] cxl/atl: Lock decoders that need address translation Message-ID: References: <20251103184804.509762-1-rrichter@amd.com> <20251103184804.509762-12-rrichter@amd.com> <6f1eaf10-071c-41ad-bda3-62eb6b1119e9@intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6f1eaf10-071c-41ad-bda3-62eb6b1119e9@intel.com> X-ClientProxiedBy: FR2P281CA0111.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:9c::15) To CYYPR12MB8750.namprd12.prod.outlook.com (2603:10b6:930:be::18) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CYYPR12MB8750:EE_|MN6PR12MB8469:EE_ X-MS-Office365-Filtering-Correlation-Id: b519bbcd-3ddb-4d67-3c4b-08de22eff2ea X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|7416014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?OCnRgvVYABZJuPT7suauV9kd6t2ChiWgAl1somZXha9CUetOi9syAGnuzZqE?= =?us-ascii?Q?1D0nNpuPF3+pFzyYZjyOef4C05pWTzbP9oZKD+eoaoSO+7835vrkxmavt5wU?= =?us-ascii?Q?DHpQbeP63sQ965zBOiTcmzCG5LL8phPNTA/AnFnDl1uhLgIvBSjn+pELEFE3?= =?us-ascii?Q?U7lp5RD70siJBMI5yuKO+2zOHM9mpOIscO2YaZKeul1y5syrHE6sqnm95OYP?= =?us-ascii?Q?EpeKudg58wwrNsplF9+XChBe6zJokzo5eqkU/4SC67eAGsMoTvZJFFkoKX40?= =?us-ascii?Q?AlActKpHjXRb0nGczGvnZ9m4aeKEzlmY8/vZO5ZOWPag2TA0knwepwOLVp1R?= =?us-ascii?Q?4D/VprCWJSLD54HF/uHTEKJal/9PC+rbjFQaJk6fciqjF8LMfrojYuY6eb21?= =?us-ascii?Q?1qsuxz31AYlIZfZFr9H0K6SNOGju9dkrnSPut0paGTL85VUO4uZcN3aM2mDD?= =?us-ascii?Q?CIBHiRLd4Xwv1obDNSmp/XdkTctTV1PHTDqrnWDfnnVSI7rG6bUvXMIE9w52?= =?us-ascii?Q?8S/yu+Ljbex6l13MkCp1qEC0/4V8Q9Y56NBBp3mhwfpdzbrnCiSYMhotpaoO?= =?us-ascii?Q?1wxFV+dL35RCqNBwoujLM0VjpXFS1hQa8vYwzKmC8qFxlEG6PNc8qNeC7VdU?= =?us-ascii?Q?rI/UbEHsFwViAvY3HquOqDgGjOqEgVmZA7dGx5EYs7nPOSpTYG+0K2iCO44d?= =?us-ascii?Q?G5iHhVug/iN0Kwx/SnJR2YR9Iv734GFHPoMbkFT4ZP+WWOqSJ6AkwYWA95rC?= =?us-ascii?Q?HnZcR8eYs79/0ol7Ny1VaAj+XL25MRm7doVeYvpvf25K+89Mn4hY2zYEenin?= =?us-ascii?Q?lNMGkV6mB1hqhlikwtUxERVrQBQhkNVrfqKhNxbcqFfQW9Y0T9ZX+aslcQqQ?= =?us-ascii?Q?dTPHT8CxvjUIhQh0HKycLm/zNhmMxyf6UdUcOuUVzPOagr7hnWZw+oLM0YPt?= =?us-ascii?Q?W25ZGTAPwll0hu/IAiIEnDv363VoKiOWozOPm+k8FYP8WkYGx9zSEj+m9Q/v?= =?us-ascii?Q?c4QbdkK7iMEvl5UNB4tYAuKB88AETcsnyfzDukrdXibw/dWMw9eM5Ot5QPL6?= =?us-ascii?Q?UWK6EyK8wxAgjgMlSPeq54KH+CeqLA/ng9wRVls+WxjnurbC88QXSjSy82+Y?= =?us-ascii?Q?x7KQDdbUBlF+eeUgfByHwAFUJm2mJJeFw3v1GC/aeMCPvWeC4+PeEkqn1PL3?= =?us-ascii?Q?3ErywxHTYIHUnL9d7kjEr9St7X7ZTbfkawPSAzR1B9QrgaesIGObFNGZqg86?= =?us-ascii?Q?Pcw08Wzl8ikwmiaJ+3jMMV+bV+o8q9MZA1aTySx9gfTglQZCpUgVx3cEmA4l?= =?us-ascii?Q?ltpPZU/Sg3wwB1liJypM/iJwmBvdLuAxkG+x/F2bSbpElIT+Jo83aUX8oGs9?= =?us-ascii?Q?BD0MXS6BKsmSORq0vjUwHgRFFhxJvkr34TXXzJipVpW1CdocikyXS7ya3hjR?= =?us-ascii?Q?bVxq64sb+9fPIOqWVxs6b4DKoOg65njk?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CYYPR12MB8750.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(7416014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MMmaf3xlxy9sRZ6sYAP9+4H9aK0T5FsWmQkFzw+hTRCMIZjwSYF6QvVilJFY?= =?us-ascii?Q?Smh89+NZtjvkkWxsPdNJn8cIeX/5qq/qnm4P4cvNefbS8r+/VhxDK+2qPQHs?= =?us-ascii?Q?mQOKD/FvpziTcuKz1X8iWefuSP9A1UZ5rdczhtUiWrHGfynJQ8Rl5E8ZUFQi?= =?us-ascii?Q?ZcE3Iw/v9mDFyjgrDCQtPHUFejIpeUhCs8ri/WGpg4lmxg3PCHMpXEl1Rppe?= =?us-ascii?Q?/ki7A0vTeezs1ZBA33SXalxmlQ24wfcoirYII2yzYJTkN3GdCh9zq7QsfgkI?= =?us-ascii?Q?9xZj5g1DS+/nfuO9I9tcnpVwJWYklGO3lHAJ4Pd8FlqI0vnqySu6fg1OCw7k?= =?us-ascii?Q?HrkXLeK4/MqqAJGivBWZjPKpiz9DSWwzPDMFOZJi2ceEtpeKAso3Jpc7OjgL?= =?us-ascii?Q?4JutheMaJf07KAzh1gEfRfeKiH6gdEdbrLPcRUZe9s2uZM0bBtShW514k3FE?= =?us-ascii?Q?eEYAHIOLWsvuyzH6B9wDRUBQsvEw9EZdBkA6Hqfry6/eP96Gg24Lbs+nSVHs?= =?us-ascii?Q?PoKfi8Mk2DddyNGd+aP221kf0lCnXIkx6rJZP72cN3jacmChPa6z45TQWgC/?= =?us-ascii?Q?vPaaIfsh2vqrKd7q7DHbu/lJ1gKVRU23O1jHucShtM6NUdzgqN0dk2sFd6dc?= =?us-ascii?Q?LBpaSQk6Ngjp6AkCmBydaokMy/yyc64HixGWJ1t6JPRT0Am36mWp6Y/zptgh?= =?us-ascii?Q?F1sbikpr7m5wdkaQydPGHEgrA4EAgwLPOGJdOEmYLp10asGXZYjlTRU0lH42?= =?us-ascii?Q?FkLM975K6UyuCqa2ma8JsyuR+Wgu1Kv4A1DAds/UroqtxEDNIXCmNjVzgx5l?= =?us-ascii?Q?sfe45IFQg+dGLoE/vh5Tdgc2e269Zbl740DPrjebYdE9sbf3wQ/w6xVKBvEN?= =?us-ascii?Q?sP0DFlTgBge+OlMfTuEnBrTjCkL7gD6HhwPUdxUh1XUZfFPEtMXUq1iL4/K+?= =?us-ascii?Q?ry+ILZAqHRtAjyHYH8v6j5NVRMuY0BenNd2GzkD+HLp0THiXV2Uyh3WCBB09?= =?us-ascii?Q?Cs8KqZ6LdZp4PRAb0+6GrgeGA+rRpjzBs8uPw0FJbr03yhXada581OlPCNZL?= =?us-ascii?Q?PS39um2syXFIHvhAB3EZyr5z9GfA72UZfWEopMxa0mWRYJaLr0ZXq9TBBArn?= =?us-ascii?Q?C2uTdvIFjcUZ88NvyyIuf5fi4gj3VUFSvP76giy5GfBQP4wz9Wfp+HV2tOgo?= =?us-ascii?Q?2d/Aa/tCqk3oiKPi1uxdnBpTRKrul2cy2IieYyP9omRWnt/QPoYk2J6xDOKx?= =?us-ascii?Q?Xp05ZgoasPef15YYC94rak7xvB/tIaZ5ZzKsf1W/E7dqS1bSbdOmJvizHsKY?= =?us-ascii?Q?dWZGAdnuM/DbDbaI5zl3Z0v6u+fno0eDYWK86dU++0Lq1SIEk1TeQbQSWkEG?= =?us-ascii?Q?HG4GA+ud9f/RIxgnZqyQ4WEyvhipLYLYf45C8CSfUc2l9wBShvE5hzcMsiKz?= =?us-ascii?Q?gcAwaD8tSnCq/a7oMY74VN5EyB1cw0KBDNV6CwXC9jz8m5MkEoNwDgymTcCf?= =?us-ascii?Q?F0bgMW8qd5YW/O3dKbPefQTQH1KClibF6HYyp7E3J5GmzGSFJ+HyOJKt5LFt?= =?us-ascii?Q?YHINNqT6mq8RqY7ppRZOCCUVtrNgO8xPhvm3Lq7W?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: b519bbcd-3ddb-4d67-3c4b-08de22eff2ea X-MS-Exchange-CrossTenant-AuthSource: CYYPR12MB8750.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Nov 2025 20:05:10.3495 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: YULz7RG2gGGZywn5nO7gRH25bR5CEwOkZ7yV0UIH0Fl3AxeHqz/r2kuDPOXovrTA6HnuB14HzZG+Z79I5IbuZg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR12MB8469 On 12.11.25 09:34:34, Dave Jiang wrote: > > > On 11/11/25 5:54 AM, Robert Richter wrote: > > On 04.11.25 10:13:34, Dave Jiang wrote: > >> > >> > >> On 11/3/25 11:47 AM, Robert Richter wrote: > >>> There is only support to translate addresses from an endpoint to its > >>> CXL host bridge, but not in the opposite direction from the bridge to > >>> the endpoint. Thus, the endpoint address range cannot be determined > >>> and setup manually for a given SPA range of a region. If the endpoint > >>> has address translation enabled, lock it to prevent the kernel from > >>> reconfiguring it. > >>> > >>> Reviewed-by: Gregory Price > >>> Signed-off-by: Robert Richter > >>> --- > >>> drivers/cxl/core/atl.c | 10 ++++++++++ > >>> 1 file changed, 10 insertions(+) > >>> > >>> diff --git a/drivers/cxl/core/atl.c b/drivers/cxl/core/atl.c > >>> index d6aa7e6d0ac5..5c15e4d12193 100644 > >>> --- a/drivers/cxl/core/atl.c > >>> +++ b/drivers/cxl/core/atl.c > >>> @@ -158,6 +158,16 @@ static int cxl_prm_translate_hpa_range(struct cxl_root *cxl_root, void *data) > >>> return -ENXIO; > >>> } > >>> > >>> + /* > >>> + * There is only support to translate from the endpoint to its > >>> + * parent port, but not in the opposite direction from the > >>> + * parent to the endpoint. Thus, the endpoint address range > >>> + * cannot be determined and setup manually. If the address range > >>> + * was translated and modified, forbid reprogramming of the > >>> + * decoders and lock them. > >>> + */ > >>> + cxld->flags |= CXL_DECODER_F_LOCK; > >> > > > >> Feels like this should be something the BIOS should enforce if that > >> is the expectation? And the kernel checks and warns if that is not > >> the case. > > > > I think this is more a limitation of the kernel implementation rather > > than the BIOS. The BIOS provides enought information by CFMWS, PRM, > > HDM and PCI topology. In theory and if there is demand for it, support > > could be added for driver region setup. > > But shouldn't the BIOS set the decoder lock rather than the kernel > setting a software lock flag based on assumption of the PRM based > setup? If BIOS locks the decoders, it cannot be removed even for the case there the OS can actually handle it. -Robert