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 D546ECD4F26 for ; Fri, 26 Jun 2026 09:25:08 +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=yxYemHQPrdk3fS8tD+TpeUcazBw+tvGubw+zL762ZGc=; b=EgWfJ7m78iATXXEOUTFDKrpFVY jLbNB4S0554tHbs5ZSyQRrwQWDLGwyLxzZvQOXLE9MxdpoD8YhdbxRYJfusMJjiyBRXTTTIhnPnh/ hg46yzILEJwBSDgKx0AGzv/Bn2aZTJKTf/8oaIOxnWe4Yl/nQWUOTU7U8x93/+7Sij+QkrQblUrfT REtm6TNUjJef6BEBwq7pgcj1jcG4DtBKaA1YauQfDSSyLn1j5troqsOGn19Ewmn8rCJ4CvB+dBU5o 6JzLXReXPV54oAqjc4OaLfzL3FhWTzQTupIuBlzxZeR7ARCK5av/+isQdVFGdGD4I6IbsEDGZJ8dD jWr5Kcsg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wd2o2-0000000AyWt-10g9; Fri, 26 Jun 2026 09:25:02 +0000 Received: from mail-wm1-x32d.google.com ([2a00:1450:4864:20::32d]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wd2nz-0000000AyVk-2bYb for linux-arm-kernel@lists.infradead.org; Fri, 26 Jun 2026 09:25:01 +0000 Received: by mail-wm1-x32d.google.com with SMTP id 5b1f17b1804b1-4924933d072so31585e9.1 for ; Fri, 26 Jun 2026 02:24:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782465898; x=1783070698; darn=lists.infradead.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=yxYemHQPrdk3fS8tD+TpeUcazBw+tvGubw+zL762ZGc=; b=q7xOoSr+8DdXuAKc+QfjccRPQkNKfSDf8ouwJTaT821t/iS5nNvQQ0WGAX81B9uRmy 1tet8yMoex1a5XvjJWl0axDZszBtJa1fx7nAB9Z2Dd3sJB7tKvZRCogQb3I/Q6a1ZCLJ acRCnNekh+UbCkIMfE8wljL7Rep/0xSglItnRYoxKx/LXUWNCZ1fGBzIhFpG1aBR/YJB 3duDSJt3bhobrje7C3+kaueywyCE8wSe7Uwbvd6hqF9xpyGk2ogbhL7TfPD+kGPmqu2v /n6FPSUX+5rX15IpFbV0NQeGWZdPvUSdhnboB26eMk4NRJ1QBEO2R6k+jiyX6oD3jDg9 UbZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782465898; x=1783070698; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=yxYemHQPrdk3fS8tD+TpeUcazBw+tvGubw+zL762ZGc=; b=U4dc49f8/dBjTPqPouXRysA4/Io3JVSP0JHsO5XlZDx3TbhBdxBedclTkK6Ylf7XQb wAzZ0vSj8mCegmt8BmFezTQkfkNKUKp+G61hSTRxZCiZBKesjTsBdG+hPx4QstWLGTfC U315cZE+GGhHtDmAt8ctwqSDamgaULrMTzi5O28kBo1w7qt+q01t/rB/HaIkyMnYT1Cz xk5qmQKY+vK5TcSTARs54pEtZ6a6lf4OLpnkz98Kqcu5m0xOliJAo2RQ2iaZB4hdl46v 5mAqbz9nNLRKpbV8o1erK/mHUUbcAbKkRUZmicsS1B5UVvpY2NCWGY0WBS9SANbGwIQi Gn4A== X-Forwarded-Encrypted: i=1; AFNElJ9AgIr3K7EjD0hnioHlQoGAAk9ROl5+gMwJkIwfiH4iYWo14wCRaRBk8N/byGj2NBLAcxXwRnYOGMmxi+s+sH6i@lists.infradead.org X-Gm-Message-State: AOJu0YyfYquLQRN2k4W6r5lFN8SWEQOOVPlUpHQwzix0dVhr/+CzBBGf W4LcjF6d2xNQzHKaJu4oFcm6MkqT1e8prI87WhUF1NwPyOu/O6iw127+gvYOR++Z9g== X-Gm-Gg: AfdE7clGlc6blVA4WArQtbm7mCNuv9cPzlWww8mggH+I5wBnMPDxPQR69T0xr8B2ISP 666LhTHKSEc025B2CGOMbZqGbbq4Jch+w2Puh5AyfQo3Lq1s9C1pcFPiy0EWbK2mq6bgGna42Ee sinQ3oiFHebCcubZW0YaV+2UsWKBBGRoeSind8PO7z/g8Dk+5xjPePgN5Ew2+T8tc6Dq4FUdLwh KR60WJAZiU0sorwL/uv1WHdumA2dvb6NU1LjPXYi1heR6S05kL5oWihrIA2f/JI7uYHBQhXsEZ7 qGg+juVM0Ty8+Z+cjfekvNPDozVHCxb4YKRH00SXPD4weTvKWKs7gCTlWWHc32bcKCAPtJ4NEMJ lkTnrmcBLoVLMiqiuNe4dwI0kRJtE0JSSqwUt3BSFXKZ4WBABtf6ARX3tJSSz9IoUJzNGmBCwC8 +nn5Dl+0nHfLKanlY3MYsY3+JOtspC+I+ioHCC9BXg/nfGwqsfrw4Q+fT90ko= X-Received: by 2002:a05:600c:3e05:b0:48a:5d55:c194 with SMTP id 5b1f17b1804b1-49269ffaa9amr983445e9.7.1782465897233; Fri, 26 Jun 2026 02:24:57 -0700 (PDT) Received: from google.com (143.11.148.146.bc.googleusercontent.com. [146.148.11.143]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-46c221d9371sm24794653f8f.21.2026.06.26.02.24.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jun 2026 02:24:56 -0700 (PDT) Date: Fri, 26 Jun 2026 09:24:52 +0000 From: Sebastian Ene To: Will Deacon Cc: catalin.marinas@arm.com, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, korneld@google.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, android-kvm@google.com, mrigendra.chaubey@gmail.com, perlarsen@google.com, suzuki.poulose@arm.com, vdonnefort@google.com, yuzenghui@huawei.com Subject: Re: [PATCH v6 7/7] KVM: arm64: Enforce strict SBZ checks in the FF-A proxy Message-ID: References: <20260626074545.433234-1-sebastianene@google.com> <20260626074545.433234-8-sebastianene@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260626_022459_683621_1DDC81EC X-CRM114-Status: GOOD ( 23.29 ) 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 Fri, Jun 26, 2026 at 10:11:14AM +0100, Will Deacon wrote: > On Fri, Jun 26, 2026 at 07:45:45AM +0000, Sebastian Ene wrote: > > Introduce a helper method ffa_check_unused_args_sbz to enforce strict > > arguments checking when the hypervisor acts as a relayer between the > > host and Trustzone. > > > > Signed-off-by: Sebastian Ene > > Reviewed-by: Vincent Donnefort > > --- > > arch/arm64/kvm/hyp/nvhe/ffa.c | 96 ++++++++++++++++++++++++++++++++++- > > 1 file changed, 95 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > > index 712811e89435..bd50ddc5b61c 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > > @@ -74,6 +74,21 @@ static u32 hyp_ffa_version; > > static bool has_version_negotiated; > > static hyp_spinlock_t version_lock; > > > > +static bool ffa_check_unused_args_sbz(struct kvm_cpu_context *ctxt, int first_reg) > > +{ > > + DECLARE_REG(u32, func_id, ctxt, 0); > > + int reg, end_reg = 7; > > + > > + if (FFA_MINOR_VERSION(hyp_ffa_version) >= 2) > > + end_reg = ARM_SMCCC_IS_64(func_id) ? 17 : 7; > > This looks like an accident waiting to happen if we don't check the major > number as well. > > I think you should just check: > > if (hyp_ffa_version >= FFA_VERSION_1_2) > > instead. > > You should also add a comment. We restrict hyp_ffa_version major to 1.0 here https://elixir.bootlin.com/linux/v7.1.1/source/arch/arm64/kvm/hyp/nvhe/ffa.c#L962 but since this is an easy fix I will include it. > > Will Sebastian