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 A5D06F557EB for ; Mon, 20 Apr 2026 08:55:24 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0OpX43y0/4r3T5hB+uPedYI7HKu6lvLhPOK215SRlmw=; b=27opT3ZAIjhCh8z5dUAfu/Q9UG cNGe6V/xDrAyXYx9EjY4fd6D/imSkfClsIALTRUXx87TwFcyaOO2zLNKM/96lB2jvah/U6xL90oNf VlSuFnD+KJcdTMsepzTVMA3KuP4e+Nuq2G4Ey83s2cxgKTMLst+1CksfYU/gT84IJK20EtomwaXDx MglcWizgwnc+Bkp0MH69n0n1PNbM/DCAlo+uH1lXiIWu86Ep62ICwljyqjAv+FlPuB+Q0dVYgMPf+ tZiYs1nTIOyM3SAT1opSBiVMTfc2F84EjmgZkx3mE/Ppmx1G1Ke26i59PaX0c1dDA/9HgOLuo5sXx 4VR1WTIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wEkPY-00000006duQ-2IGX; Mon, 20 Apr 2026 08:55:20 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wEkPV-00000006du0-2VrW for linux-arm-kernel@lists.infradead.org; Mon, 20 Apr 2026 08:55:18 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 740864454E; Mon, 20 Apr 2026 08:55:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3136CC19425; Mon, 20 Apr 2026 08:55:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776675316; bh=O5qEzAlW1XZCYge9c/pa7CeB6wV9ZdCNQTkECJw9vIM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aMYjgzS6ZqypodZLc5FGiz/NHxqDQXP5Kez4CJHNExX767+MBxlUDZlzqmsvKpWh5 YdhE4rJTK+WFMAWQTPYRQXXB2C0/8c1NvRLwZezaY5LP/oLF2X3qb3gXOb4o72zqoy T46CAHEkGLlMZzkTu2vqLEvlB4w1evnQUZl3b9Eu6vkXVlOFRyd+NwnjuCwXhPz+Qa sTWm7gYGy4AAFx7MftHJX38DTdx1xjm+Zs8f1cY85PeyBfAfCTbyAqTLFCRqUVWe2t xROkg/I/FRv7jow6EHFweKn+OVy+1GN7dHDsc0OqJGM2B7YGS7i266au38JBxvDI9u bbMWic9XHg+Nw== Date: Mon, 20 Apr 2026 09:55:09 +0100 From: Will Deacon To: Yeoreum Yun Cc: Marc Zyngier , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com, roberto.sassu@huawei.com, dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com, peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca, sudeep.holla@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com Subject: Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver Message-ID: References: <20260417175759.3191279-1-yeoreum.yun@arm.com> <20260417175759.3191279-5-yeoreum.yun@arm.com> <87se8sbozv.wl-maz@kernel.org> <87pl3vb5bm.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260420_015517_755313_0C608897 X-CRM114-Status: GOOD ( 29.38 ) 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 Sun, Apr 19, 2026 at 12:12:44PM +0100, Yeoreum Yun wrote: > Hi Marc, > > > On Sat, 18 Apr 2026 11:34:30 +0100, > > Yeoreum Yun wrote: > > > > > > > > @@ -2035,6 +2037,16 @@ static int __init ffa_init(void) > > > > > u32 buf_sz; > > > > > size_t rxtx_bufsz = SZ_4K; > > > > > > > > > > + /* > > > > > + * When pKVM is enabled, the FF-A driver must be initialized > > > > > + * after pKVM initialization. Otherwise, pKVM cannot negotiate > > > > > + * the FF-A version or obtain RX/TX buffer information, > > > > > + * which leads to failures in FF-A calls. > > > > > + */ > > > > > + if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() && > > > > > + !is_kvm_arm_initialised()) > > > > > + return -EPROBE_DEFER; > > > > > + > > > > > > > > That's still fundamentally wrong: pkvm is not ready until > > > > finalize_pkvm() has finished, and that's not indicated by > > > > is_kvm_arm_initialised(). > > > > > > Thanks. I miss the TSC bit set in here. > > > > That's the least of the problems. None of the infrastructure is in > > place at this stage... > > > > > IMHO, I'd like to make an new state check function -- > > > is_pkvm_arm_initialised() so that ff-a driver to know whether > > > pkvm is initialised. > > > > Doesn't sound great, TBH. > > > > > or any other suggestion? > > > > Instead of adding more esoteric predicates, I'd rather you build on an > > existing infrastructure. You have a dependency on KVM, use something > > that is designed to enforce dependencies. Device links spring to mind > > as something designed for that. > > > > Can you look into enabling this for KVM? If that's possible, then it > > should be easy enough to delay the actual KVM registration after pKVM > > is finalised. > > or what about some event notifier? Just like: This seems a bit over-engineered to me. Why don't you just split the FF-A initialisation into two steps: an early part which does the version negotiation and then a later part which can fit in with whatever dependencies you have on the TPM? Will