From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4E74DC44501 for ; Wed, 15 Jul 2026 12:19:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jhgWz6vHk27ED/iPmnJILlRupwiQTb8LD817jdHgI/8=; b=EXlq+d4artWkgyb4jak5f0NATJ vdhXwRvVxTpnkyXj3LGpnC13DQKXUSRYWtaAaQn8fZxiI68oasmkkJgT5aN+kvvkIt+U2wDxTgNoL Ob9fF3uyil5G6i7njV0PZEj1W6EHShMddHm/oE63fpTtNNHs5Yl0tEhNqs57pEAc/w14w2fhyk0cn igYJUZuqZBWydGafFFMsKFDmXgdaXaO+ggGRbCJRL6yyZbO8Qp1ZbfwOma7drYsYZ69uGgZ5XrL0r 060zrorzOWKPWJibEQcwhQdaE42YtQ2PwrdYEUpvpUfZFL4FNvVv+jkqAk4GJii8PzGwk1Y3+iUfV OhHzfclw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wjyaZ-0000000ElKU-3ZT7; Wed, 15 Jul 2026 12:19:47 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wjyaV-0000000ElJF-3nMe for linux-arm-kernel@lists.infradead.org; Wed, 15 Jul 2026 12:19:46 +0000 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 068432F; Wed, 15 Jul 2026 05:19:37 -0700 (PDT) Received: from [10.1.39.37] (unknown [10.1.39.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5640F3F7B4; Wed, 15 Jul 2026 05:19:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784117981; bh=1Tt0MZGEStJa1QvPCBaLpbX+2rLiZ4I/VM9Ny/bJNBE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=U1mfcg9QIS5BoO/4wu//17ztJSflgRoB9KQjRjBikCmilifzyw6nVovS43XmGPDtn 4cMHAPRhcRgkMscJR0+GbCwtD5Vw65ifrz/ECvQ6Q7ZrvDfG/DJH6/Wich4aXymhWI 21sLyoTBBqddcTDUvDNaVr+eHAlRJRLMnW87X+w8= Message-ID: Date: Wed, 15 Jul 2026 13:19:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 6/6] coco: guest: arm64: Replace dummy CCA device with sysfs ABI Content-Language: en-GB To: "Aneesh Kumar K.V (Arm)" , linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Andre Przywara References: <20260707081351.1680209-1-aneesh.kumar@kernel.org> <20260707081351.1680209-7-aneesh.kumar@kernel.org> From: Suzuki K Poulose In-Reply-To: <20260707081351.1680209-7-aneesh.kumar@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260715_051943_983041_4A7FF2BB X-CRM114-Status: GOOD ( 12.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 07/07/2026 09:13, Aneesh Kumar K.V (Arm) wrote: > The SMCCC firmware driver now creates the arm-smccc platform device and > instantiates the CCA RSI auxiliary devices once the RSI ABI is discovered. > The arm64-specific arm-cca-dev platform device stub is therefore no longer > needed. > > However, userspace has used the arm-cca-dev platform device to detect Arm > CCA Realm guests [1]. Removing it without a replacement would break that > detection and would also leave userspace depending on kernel device-model > details. > > Add /sys/firmware/cca/realm_guest as a stable, architecture-provided ABI > for detecting whether the kernel is running as an Arm CCA Realm guest. The > file returns 1 in Realm world and 0 otherwise, similar to the existing s390 > /sys/firmware/uv/prot_virt_guest interface for protected virtualization > guests. > > Remove the dummy arm-cca-dev registration now that userspace has a > dedicated CCA Realm guest indicator, and document the new ABI in > Documentation/ABI/testing/sysfs-firmware-cca. > > [1] https://lore.kernel.org/all/4a7d84b2-2ec4-4773-a2d5-7b63d5c683cf@arm.com > > Signed-off-by: Aneesh Kumar K.V (Arm) Acked-by: Suzuki K Poulose