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 207E626E16A for ; Fri, 10 Oct 2025 15:23:09 +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=1760109791; cv=none; b=M6sRFsow8H1/Db0dAgD5h3iWaJ5lev8bZ1s3/IOJP1/HHb1BoouK9Ac7gl89ICbxYyktdI0uU1xc5ZDAvB3E7ENP1ofdrrPKlv9FdV7wQq1tAJY4+Qk2eClTwYQBohXlmErKrqTVuiXTGLoxcmbiCJ303KAPVvWtR4Ya9ph95pI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760109791; c=relaxed/simple; bh=b6U6I+R3YkCWG8VlZzjudcPduzhx6TE6xWqusLNS/6s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CQ8pMeZSefZoAWhQT+afzsIYmtu1BgVJiUFUHtEo/jPxayAiPzl1Jc3RWJy8PRAp7ZIYp+z4kZDU9dRZ32hwgzVPj3UxULlBcG6GfTxbKq1FFX/eJxxH1W3Tiz2n224Zb6qV7OuYLvnHkVxxglcu17P2VijbsxNShZfkL0PPwLQ= 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 743511063; Fri, 10 Oct 2025 08:23:01 -0700 (PDT) Received: from [192.168.20.16] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2DDFB3F66E; Fri, 10 Oct 2025 08:23:09 -0700 (PDT) Message-ID: <281dcb37-9e50-42ed-918d-3a527e738e6e@arm.com> Date: Fri, 10 Oct 2025 10:23:08 -0500 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver 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 , Will Deacon , Steven Price , Gavin Shan , Suzuki K Poulose , Sami Mujawar References: <20251008132758.784275-1-aneesh.kumar@kernel.org> Content-Language: en-US From: Jeremy Linton In-Reply-To: <20251008132758.784275-1-aneesh.kumar@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/8/25 8:27 AM, Aneesh Kumar K.V (Arm) wrote: > Make preparatory updates to the ARM CCA guest driver: > > - Switch from using a platform device to a faux device (based on > feedback in [1]) > - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the > host driver can register an equivalent `arm-rmi-dev` > > These changes are purely structural and introduce no new functionality. > Subsequent patches will extend this driver to add guest device > assignment support. > > [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh > > Signed-off-by: Aneesh Kumar K.V (Arm) > --- > NOTE: > This patch is sent early outside the patchseries to avoid userspace from > depending on the presence of the newly introduced platform device. > The platform device was added in v6.14-rc1. At this point, changing the platform device name also breaks systemd's confidential vm detection, because its using this device name as the first step. > > arch/arm64/include/asm/rsi.h | 2 +- > arch/arm64/kernel/rsi.c | 15 ----- > drivers/virt/coco/arm-cca-guest/Makefile | 3 + > .../{arm-cca-guest.c => arm-cca.c} | 65 +++++++++++-------- > 4 files changed, 41 insertions(+), 44 deletions(-) > rename drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c => arm-cca.c} (85%) > > diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h > index b42aeac05340..26ef6143562b 100644 > --- a/arch/arm64/include/asm/rsi.h > +++ b/arch/arm64/include/asm/rsi.h > @@ -10,7 +10,7 @@ > #include > #include > > -#define RSI_PDEV_NAME "arm-cca-dev" > +#define RSI_DEV_NAME "arm-rsi-dev" > > DECLARE_STATIC_KEY_FALSE(rsi_present); > > diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c > index ce4778141ec7..569ef08750e5 100644 > --- a/arch/arm64/kernel/rsi.c > +++ b/arch/arm64/kernel/rsi.c > @@ -140,18 +140,3 @@ void __init arm64_rsi_init(void) > > static_branch_enable(&rsi_present); > } > - > -static struct platform_device rsi_dev = { > - .name = RSI_PDEV_NAME, > - .id = PLATFORM_DEVID_NONE > -}; > - > -static int __init arm64_create_dummy_rsi_dev(void) > -{ > - if (is_realm_world() && > - platform_device_register(&rsi_dev)) > - pr_err("failed to register rsi platform device\n"); > - return 0; > -} > - > -arch_initcall(arm64_create_dummy_rsi_dev) > diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile > index 69eeba08e98a..609462ea9438 100644 > --- a/drivers/virt/coco/arm-cca-guest/Makefile > +++ b/drivers/virt/coco/arm-cca-guest/Makefile > @@ -1,2 +1,5 @@ > # SPDX-License-Identifier: GPL-2.0-only > +# > obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o > + > +arm-cca-guest-$(CONFIG_TSM) += arm-cca.o > diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c > similarity index 85% > rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c > rename to drivers/virt/coco/arm-cca-guest/arm-cca.c > index 0c9ea24a200c..89d9e7f8eb5d 100644 > --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c > +++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c > @@ -1,8 +1,9 @@ > // SPDX-License-Identifier: GPL-2.0-only > /* > - * Copyright (C) 2023 ARM Ltd. > + * Copyright (C) 2025 ARM Ltd. > */ > > +#include > #include > #include > #include > @@ -181,52 +182,60 @@ static int arm_cca_report_new(struct tsm_report *report, void *data) > return ret; > } > > -static const struct tsm_report_ops arm_cca_tsm_ops = { > +static const struct tsm_report_ops arm_cca_tsm_report_ops = { > .name = KBUILD_MODNAME, > .report_new = arm_cca_report_new, > }; > > -/** > - * arm_cca_guest_init - Register with the Trusted Security Module (TSM) > - * interface. > - * > - * Return: > - * * %0 - Registered successfully with the TSM interface. > - * * %-ENODEV - The execution context is not an Arm Realm. > - * * %-EBUSY - Already registered. > - */ > -static int __init arm_cca_guest_init(void) > +static void unregister_cca_tsm_report(void *data) > +{ > + tsm_report_unregister(&arm_cca_tsm_report_ops); > +} > + > +static int cca_tsm_probe(struct faux_device *fdev) > { > int ret; > > if (!is_realm_world()) > return -ENODEV; > > - ret = tsm_report_register(&arm_cca_tsm_ops, NULL); > - if (ret < 0) > + ret = tsm_report_register(&arm_cca_tsm_report_ops, NULL); > + if (ret < 0) { > pr_err("Error %d registering with TSM\n", ret); > + return ret; > + } > + > + ret = devm_add_action_or_reset(&fdev->dev, unregister_cca_tsm_report, NULL); > + if (ret < 0) { > + pr_err("Error %d registering devm action\n", ret); > + unregister_cca_tsm_report(NULL); > + return ret; > + } > > return ret; > } > -module_init(arm_cca_guest_init); > > -/** > - * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM) > - * interface. > - */ > -static void __exit arm_cca_guest_exit(void) > +static struct faux_device *cca_tsm; > + > +static const struct faux_device_ops cca_device_ops = { > + .probe = cca_tsm_probe, > +}; > + > +static int __init cca_tsm_init(void) > { > - tsm_report_unregister(&arm_cca_tsm_ops); > + cca_tsm = faux_device_create(RSI_DEV_NAME, NULL, &cca_device_ops); > + if (!cca_tsm) > + return -ENOMEM; > + return 0; > } > -module_exit(arm_cca_guest_exit); > +module_init(cca_tsm_init); > > -/* modalias, so userspace can autoload this module when RSI is available */ > -static const struct platform_device_id arm_cca_match[] __maybe_unused = { > - { RSI_PDEV_NAME, 0}, > - { } > -}; > +static void __exit cca_tsm_exit(void) > +{ > + faux_device_destroy(cca_tsm); > +} > +module_exit(cca_tsm_exit); > > -MODULE_DEVICE_TABLE(platform, arm_cca_match); > MODULE_AUTHOR("Sami Mujawar "); > MODULE_DESCRIPTION("Arm CCA Guest TSM Driver"); > MODULE_LICENSE("GPL");