From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792515940; b=C6ih/O7Wv5MOorThp0g+HRJXbf9FSLIjEM5DKI374BsWbuE1NAwkugYM5AEiLLZk6Bi8 J1RNFFV5cHMykY4o1ZmMZ6lE3UoQzCbLZp5F0vttFprs8z6mvcnJhfdsVtoDDGuOtfVvm bRA4USsY/2o7IyT/egPQqay9zJUUoe7JP+gIcR5ncSzfKec/46P6FAz/vV04CZ9rNwyAf NjsMlk2SQm2X3QomE49n2UNgbdhd+7+idMhjHxUlF9vyah7KW30F6wJEwws9SXLJzwlSI djIUZeHU+OVFwlmjMJ5dPR5LCi5m0pvFy1lXYlYweIQewhMOLhEXo0OLnzA0ZP4nk6w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792515940; h=DMARC-Filter:Received:Received:DKIM-Signature:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=sfkxhp2YPni25pk9lAqihLFxxjnCFT2yCSxPUm/Y7qE=; b=VRbULFqcQQGZ5Hm7hlFAMCILML5r9xxSS1RX/lpMhziqv43bw4dsGwKEo1qqudosW/S7 eDD1VIEMpH1wglMtvRIk/c5l2nrEOtP7b7+Sz67UkAlBod7fggs9cqaX43OH+VEP+yYN6 PlRRvk5yf0A1H5UbQF4zIR6nszpZ04G2tXYPREdfURKk3rIwaE7ZiEUhhem8TV9S2hfTS m10CZvzSMnQwvY1EJFn3dh4RiCnbhnOzLJWEdwOqx8SamugzfDCJaTfGtHNmb+/Wx8U7j kaauC5/Jw0g99i/Poh/vkxy+45fY+OXSOHBtoE/eTFzKbJ2iQPzlch8LYhFSiN96xnA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=C5kzCuEo; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CA61E606A320 for ; Tue, 20 Oct 2026 17:05:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org CA61E606A320 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=C5kzCuEo 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 F28FB1596; Tue, 20 Oct 2026 10:05:35 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9D8973FA32; Tue, 20 Oct 2026 10:05:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1792515939; bh=Neo80ApyG7pQv+dI5x32cAG8lDQTvw41mtuVfq5grwk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=C5kzCuEoVbtzk+iW3NiFBraTqEDwSW05GvXjZNIJKIssRTnabAGY5qnWFeWvi7Qrp TsaXg2Z0gZK/lvymuXrTeeDT/lr/mR7zPSYfXJYakHbJbwEpSieg2+zHedWdYsLZYn HUDilYCH9SJKM7sJBM72OfetZnIlq+7/+PNz4g5o= Date: Tue, 20 Oct 2026 18:05:35 +0100 From: Yeoreum Yun To: Jason Gunthorpe Cc: Yeoreum Yun , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Lorenzo Pieralisi , Catalin Marinas , Suzuki Poulose , Steven Price , Sami Mujawar , "Aneesh Kumar K.V" , Jiri Pirko , GONG Ruiqi Subject: Re: [PATCH RFC 0/3] firmware: arm_firme: introduce FIRME support for host attestation Message-ID: References: <20261020124536.GM14213@ziepe.ca> <20261020135006.GO14213@ziepe.ca> <20261020143620.GP14213@ziepe.ca> <20261020145806.GQ14213@ziepe.ca> <20261020164755.GR14213@ziepe.ca> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261020164755.GR14213@ziepe.ca> On Tue, Oct 20, 2026 at 01:47:55PM -0300, Jason Gunthorpe wrote: > On Tue, Oct 20, 2026 at 04:18:45PM +0100, Yeoreum Yun wrote: > > On Tue, Oct 20, 2026 at 11:58:06AM -0300, Jason Gunthorpe wrote: > > > On Tue, Oct 20, 2026 at 03:43:47PM +0100, Yeoreum Yun wrote: > > > > On Tue, Oct 20, 2026 at 11:36:20AM -0300, Jason Gunthorpe wrote: > > > > > On Tue, Oct 20, 2026 at 03:13:19PM +0100, Yeoreum Yun wrote: > > > > > > > I wouldn't over complicated it. We already have smccc bus to do this, > > > > > > > we don't need layered stacks of busses here. Just change smccc bus to > > > > > > > be able to break up the multi-function SMC into several devices. > > > > > > > > > > > > I think my explaination was poor. Apologise... > > > > > > I'm not saying another bus making but just wrapper of smccc-bus APIs > > > > > > for firme specific and definietly, this would separate the > > > > > > multi-function SMC to defien each firme device (attestation and IDE). > > > > > > > > > > I don't see that kind of complexity is necessary.. I think it is > > > > > better to just have the root smcc bus spawn them > > > > > > > > > > > But, the *base* is common. and I couldn't find any proper location to > > > > > > deploy *common* code unless making arm_firme. > > > > > > > > > > What common code excatly? > > > > > > > > > > There shouldn't be? Getting an attestation is entirely orthogonal to > > > > > set link ide, for example? > > > > > > > > > > If you can identify what you think would ever be common that might > > > > > help clarifgy what to do.. > > > > > > > > I mean the BASE service of firme and typical example is shared buffer > > > > allocation. I agree IDE and attestaion service are orthogonal. but > > > > in case of base-service is not. it could be used for both service. > > > > > > It doesn't look like it needs a "shared buffer", just allocate it > > > right before invoking the SMC that needs the memory. Use a simple > > > library function to help allocate it. No need for a struct device > > > layer. > > > > Retrieving a PAT requires a buffer shared between the worlds. Before > > allocating that buffer, the driver needs to query its requirements > > through the BASE service's feature-query calls. > > So? Make the query, allocate the buffer, get the token, free > it. Simple, one driver, no convoluted flows. Use a little library > style call or inline to reduce duplication if eventually necessary. > > > Considering possible extensions to the BASE service, my preference > > would be to expose these operations through firme_device rather than > > standalone library functions. The intention is to keep access to the > > BASE service within FIRME-specific drivers and provide a consistent > > interface for those drivers. > > Try not to overdesign things. If we don't know we need it now based on > how the current spec works don't imagine something else. > > ARM spec design is informed by Linux implemetnation. Having a sane > simple implemtnation in Linux will motivate future specs changes to > align better. > > > If we implments this with library, are you thinking that file should > > be located at driver/firmware/arm_firme or other place? though we make it > > with library, I still think it should be located at > > driver/firmware/arm_firme or some place in arch/arm64, but as > > perspective abstraction to mange firme helpers in one place, > > I think this design seems good. > > Will has indicated a preference for driver/firwmare Okay. with this let me make a driver/firmware/arm_firme as library not a module format and make this library APIs (base, attestation) to be used attestation and other. This means device / driver registeration with smccc and done in driver/attestation/provider but use the APIs from /driver/firmware/arm_firme. Thanks for clarification. let me post next RFCv2 after initial attestation subsystem is settled in :) -- Sincerely, Yeoreum Yun