From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8D7E12E7E for ; Mon, 9 Jun 2025 08:02:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749456174; cv=none; b=K5Y5UaHld+xLq8Tn0klj9J8g0N+Umf12/wUuC98enlLcZx3p7oSt8AJf1qgj1c5/kqptVh6RfsN6lmKBjcWfp+GAmXrPZ0gl0zu570bBc0KZ1ceCt4tKVfRrVv5NdKU6rzIbmG0KrKUByNIvOYlLp9jH80bPYVxSFmpyViBCU6A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749456174; c=relaxed/simple; bh=7rNEGkBan0eoSoeImZk17eMKapBrfhPQlHCxzftBoV4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uiohEYyevuAT1v/96R2yZO7iUY2Szu6KNYU2k8XfoBexmCm59nV+3RDX+8bR3nm25Mpx06NlVirRKIKRsArPrdo4Mil9mQ2/tpSlPancYbENB0PJLYwS33+qQtDHSzQrFbaTb6wMe/DI/DyIU5xIfdU/SUUTwado5CC9j43pcdU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=XOUUZeRh; arc=none smtp.client-ip=209.85.221.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="XOUUZeRh" Received: by mail-wr1-f45.google.com with SMTP id ffacd0b85a97d-3a522224582so2458716f8f.3 for ; Mon, 09 Jun 2025 01:02:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1749456171; x=1750060971; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=8jEVH42C4V4RM7OPBVpernVaAA5iY2pieNHM7q6gnRY=; b=XOUUZeRhcCWPkbpdWFK+777IOH5Lkfe9he9d4M1zr55rqauRYy6W/OJr8mDaJPDoGJ vNqDypf3AtZcqX3ESFnJ2Mp/BFFGdR4CwgHzX1+tzcznSVKCi9KcWfDWn9m/3cUEB/4P 3Uugfv39Z9rtAP0tconqG5JOuMH8HOX6VUcz8GYHMAz2Q2n8dgm1OehIaPMaHYRXoOj/ Sm3lQO/UhFcAceSHlhx8/Byf6jlWRA4znDkmsPW7jwHd8V+TIJSyUBk0eEplxP/sOKXZ lZMqpre9QazG6gR7YOFsAAmxarkWL3MLSm645g0DR6RhFvcE5jTLgPRK0fjv0Ho7So2S kEQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749456171; x=1750060971; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=8jEVH42C4V4RM7OPBVpernVaAA5iY2pieNHM7q6gnRY=; b=kz2HgWUfsnAIpxCTstsSIvQMFuMi/akPIzovl2V3NUWUZk6DcJP37nDKF0lpLNFoxO FoeOLLjg7lE7C2xHcqEu48e+cJYbh829B7viEFFodVeYLN30o+aOM/gd0nTpvh5Q1X4L J5f5objgMZMLX3pfbTC85QDdTcxvPc+RKPWRcQRPqXhn0XiSxz2UKXD586m//JZOYILP GsNF3O7Cn0X3MzGrO3v+CXv2czOZmciNXBVIjpmofZn4WWFSkd0WnU1md7/wGiSTYEgd 48GmTCOnCGJ0KV4mTX/MrDUOqwpHYC6NT3P33xDkLMzUrfDLgeg1s74BQsThYYOmk/DJ dlbg== X-Forwarded-Encrypted: i=1; AJvYcCWDPfb4eib2GGN2oodxX9/0BBgc76dkI+kCcrMx4MkMaD8hd4DAjm9dtqUylmfQ7VCfP0+FqkhqVTG217k=@vger.kernel.org X-Gm-Message-State: AOJu0YxRaY8AdOfX1UVykbP0DL3G/vHey3x7Rd83o3vtBUrOvhGZpDWu MgUdI33uBd+j2J5unqSxZRSv8yTnRqc0jH7elJ+xr448Bbay1CeeOiMF7hrfCjOLreA= X-Gm-Gg: ASbGnctqnzIdsCsdWzKoeJLRMqfvVqPeHb8PCeRdbiyyQYLWYpSsQHoNPw/Pw9Q7/Fo RnkdUF8J8jQK26ARQslCaMCg5vOSKFFNF9nd0KUzxqfYC7llQWH6Jewib66vA+Dx5CGNyjmnN7y 5TIKWYrhWsy9tiCQWBeHP8MzOdjM4EriL4mV3XA200kuALX+6bKn81vjP2+PPIuaeKxpdBXa8F5 +2KnwJm7i8OafIuf37xlXn1y2G4kdpntS1h5QTnMYP9aJ1EsjgWBTuSj0VwGQ56qUvAGSJ5BC8M QQ1sV367RO6cTdaKEemqXSvzQmPr/pDAru6dTcJFrJY/PJhEzm/Er69Fo5XlK5iJ9sM= X-Google-Smtp-Source: AGHT+IFvRF+XgG4wncrB+z3N9gR+KJXYed7DBae2qonjrbB3EvonuPccnEzcGgZ+DZftSs3V+DzeWQ== X-Received: by 2002:a5d:64ce:0:b0:3a4:cbc6:9db0 with SMTP id ffacd0b85a97d-3a531cb90fdmr8885623f8f.51.1749456171200; Mon, 09 Jun 2025 01:02:51 -0700 (PDT) Received: from [192.168.0.20] ([212.21.159.167]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a53245275esm8868270f8f.76.2025.06.09.01.02.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Jun 2025 01:02:50 -0700 (PDT) Message-ID: <175eedc5-d82a-4b3a-bce6-2caf625597ca@suse.com> Date: Mon, 9 Jun 2025 11:02:49 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 03/20] x86/virt/seamldr: Introduce a wrapper for P-SEAMLDR SEAMCALLs To: Chao Gao Cc: linux-coco@lists.linux.dev, x86@kernel.org, kvm@vger.kernel.org, seanjc@google.com, pbonzini@redhat.com, eddie.dong@intel.com, kirill.shutemov@intel.com, dave.hansen@intel.com, dan.j.williams@intel.com, kai.huang@intel.com, isaku.yamahata@intel.com, elena.reshetova@intel.com, rick.p.edgecombe@intel.com, Farrah Chen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org References: <20250523095322.88774-1-chao.gao@intel.com> <20250523095322.88774-4-chao.gao@intel.com> From: Nikolay Borisov Content-Language: en-US Autocrypt: addr=nik.borisov@suse.com; keydata= xsFNBGcrpvIBEAD5cAR5+qu30GnmPrK9veWX5RVzzbgtkk9C/EESHy9Yz0+HWgCVRoNyRQsZ 7DW7vE1KhioDLXjDmeu8/0A8u5nFMqv6d1Gt1lb7XzSAYw7uSWXLPEjFBtz9+fBJJLgbYU7G OpTKy6gRr6GaItZze+r04PGWjeyVUuHZuncTO7B2huxcwIk9tFtRX21gVSOOC96HcxSVVA7X N/LLM2EOL7kg4/yDWEhAdLQDChswhmdpHkp5g6ytj9TM8bNlq9I41hl/3cBEeAkxtb/eS5YR 88LBb/2FkcGnhxkGJPNB+4Siku7K8Mk2Y6elnkOctJcDvk29DajYbQnnW4nhfelZuLNupb1O M0912EvzOVI0dIVgR+xtosp66bYTOpX4Xb0fylED9kYGiuEAeoQZaDQ2eICDcHPiaLzh+6cc pkVTB0sXkWHUsPamtPum6/PgWLE9vGI5s+FaqBaqBYDKyvtJfLK4BdZng0Uc3ijycPs3bpbQ bOnK9LD8TYmYaeTenoNILQ7Ut54CCEXkP446skUMKrEo/HabvkykyWqWiIE/UlAYAx9+Ckho TT1d2QsmsAiYYWwjU8igXBecIbC0uRtF/cTfelNGrQwbICUT6kJjcOTpQDaVyIgRSlUMrlNZ XPVEQ6Zq3/aENA8ObhFxE5PLJPizJH6SC89BMKF3zg6SKx0qzQARAQABzSZOaWtvbGF5IEJv cmlzb3YgPG5pay5ib3Jpc292QHN1c2UuY29tPsLBkQQTAQoAOxYhBDuWB8EJLBUZCPjT3SRn XZEnyhfsBQJnK6byAhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJECRnXZEnyhfs XbIQAJxuUnelGdXbSbtovBNm+HF3LtT0XnZ0+DoR0DemUGuA1bZAlaOXGr5mvVbTgaoGUQIJ 3Ejx3UBEG7ZSJcfJobB34w1qHEDO0pN9orGIFT9Bic3lqhawD2r85QMcWwjsZH5FhyRx7P2o DTuUClLMO95GuHYQngBF2rHHl8QMJPVKsR18w4IWAhALpEApxa3luyV7pAAqKllfCNt7tmed uKmclf/Sz6qoP75CvEtRbfAOqYgG1Uk9A62C51iAPe35neMre3WGLsdgyMj4/15jPYi+tOUX Tc7AAWgc95LXyPJo8069MOU73htZmgH4OYy+S7f+ArXD7h8lTLT1niff2bCPi6eiAQq6b5CJ Ka4/27IiZo8tm1XjLYmoBmaCovqx5y5Xt2koibIWG3ZGD2I+qRwZ0UohKRH6kKVHGcrmCv0J YO8yIprxgoYmA7gq21BpTqw3D4+8xujn/6LgndLKmGESM1FuY3ymXgj5983eqaxicKpT9iq8 /a1j31tms4azR7+6Dt8H4SagfN6VbJ0luPzobrrNFxUgpjR4ZyQQ++G7oSRdwjfIh1wuCF6/ mDUNcb6/kA0JS9otiC3omfht47yQnvod+MxFk1lTNUu3hePJUwg1vT1te3vO5oln8lkUo9BU knlYpQ7QA2rDEKs+YWqUstr4pDtHzwQ6mo0rqP+zzsFNBGcrpvIBEADGYTFkNVttZkt6e7yA LNkv3Q39zQCt8qe7qkPdlj3CqygVXfw+h7GlcT9fuc4kd7YxFys4/Wd9icj9ZatGMwffONmi LnUotIq2N7+xvc4Xu76wv+QJpiuGEfCDB+VdZOmOzUPlmMkcJc/EDSH4qGogIYRu72uweKEq VfBI43PZIGpGJ7TjS3THX5WVI2YNSmuwqxnQF/iVqDtD2N72ObkBwIf9GnrOgxEyJ/SQq2R0 g7hd6IYk7SOKt1a8ZGCN6hXXKzmM6gHRC8fyWeTqJcK4BKSdX8PzEuYmAJjSfx4w6DoxdK5/ 9sVrNzaVgDHS0ThH/5kNkZ65KNR7K2nk45LT5Crjbg7w5/kKDY6/XiXDx7v/BOR/a+Ryo+lM MffN3XSnAex8cmIhNINl5Z8CAvDLUtItLcbDOv7hdXt6DSyb65CdyY8JwOt6CWno1tdjyDEG 5ANwVPYY878IFkOJLRTJuUd5ltybaSWjKIwjYJfIXuoyzE7OL63856MC/Os8PcLfY7vYY2LB cvKH1qOcs+an86DWX17+dkcKD/YLrpzwvRMur5+kTgVfXcC0TAl39N4YtaCKM/3ugAaVS1Mw MrbyGnGqVMqlCpjnpYREzapSk8XxbO2kYRsZQd8J9ei98OSqgPf8xM7NCULd/xaZLJUydql1 JdSREId2C15jut21aQARAQABwsF2BBgBCgAgFiEEO5YHwQksFRkI+NPdJGddkSfKF+wFAmcr pvICGwwACgkQJGddkSfKF+xuuxAA4F9iQc61wvAOAidktv4Rztn4QKy8TAyGN3M8zYf/A5Zx VcGgX4J4MhRUoPQNrzmVlrrtE2KILHxQZx5eQyPgixPXri42oG5ePEXZoLU5GFRYSPjjTYmP ypyTPN7uoWLfw4TxJqWCGRLsjnkwvyN3R4161Dty4Uhzqp1IkNhl3ifTDYEvbnmHaNvlvvna 7+9jjEBDEFYDMuO/CA8UtoVQXjy5gtOhZZkEsptfwQYc+E9U99yxGofDul7xH41VdXGpIhUj 4wjd3IbgaCiHxxj/M9eM99ybu5asvHyMo3EFPkyWxZsBlUN/riFXGspG4sT0cwOUhG2ZnExv XXhOGKs/y3VGhjZeCDWZ+0ZQHPCL3HUebLxW49wwLxvXU6sLNfYnTJxdqn58Aq4sBXW5Un0Q vfbd9VFV/bKFfvUscYk2UKPi9vgn1hY38IfmsnoS8b0uwDq75IBvup9pYFyNyPf5SutxhFfP JDjakbdjBoYDWVoaPbp5KAQ2VQRiR54lir/inyqGX+dwzPX/F4OHfB5RTiAFLJliCxniKFsM d8eHe88jWjm6/ilx4IlLl9/MdVUGjLpBi18X7ejLz3U2quYD8DBAGzCjy49wJ4Di4qQjblb2 pTXoEyM2L6E604NbDu0VDvHg7EXh1WwmijEu28c/hEB6DwtzslLpBSsJV0s1/jE= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/9/25 10:53, Chao Gao wrote: >>> +config INTEL_TDX_MODULE_UPDATE >>> + bool "Intel TDX module runtime update" >>> + depends on INTEL_TDX_HOST >>> + help >>> + This enables the kernel to support TDX module runtime update. This allows >>> + the admin to upgrade the TDX module to a newer one without the need to >>> + terminate running TDX guests. >>> + >>> + If unsure, say N. >>> + >> >> WHy should this be conditional? >> > > Good question. I don't have a strong reason, but here are my considerations: > > 1. Runtime updates aren't strictly necessary for TDX functionalities. Users can > update the TDX module via BIOS updates and reboot if service downtime isn't > a concern. > > 2. Selecting TDX module updates requires selecting FW_UPLOAD and FW_LOADER, > which I think will significantly increase the kernel size if FW_UPLOAD/LOADER > won't otherwise be selected. If size is a consideration (but given the size of machines that are likely to run CoCo guests I'd say it's not) then don't make this a user-configurable option but rather make it depend on TDX being selected and FW_UPLOAD/FW_LOADER being selected. I'd rather keep the user visible options to a minimum, especially something such as this update functionality. But in any case I'd like to hear other opinions as well. > > It may or may not be wise to assume that most TDX users will enable TDX module > updates. so, I'm taking a conservative approach by making it optional. The > resulting code isn't that complex, as CONFIG_INTEL_TDX_MODULE_UPDATE > appears in only two places: > > 1. in the Makefile: > > obj-y += seamcall.o tdx.o > obj-$(CONFIG_INTEL_TDX_MODULE_UPDATE) += seamldr.o > > 2. in the seamldr.h: > > #ifdef CONFIG_INTEL_TDX_MODULE_UPDATE > extern struct attribute_group seamldr_group; > #define SEAMLDR_GROUP (&seamldr_group) > int get_seamldr_info(void); > void seamldr_init(struct device *dev); > #else > #define SEAMLDR_GROUP NULL > static inline int get_seamldr_info(void) { return 0; } > static inline void seamldr_init(struct device *dev) { } > #endif > > That said, I'm open to keeping or dropping the Kconfig option.