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 6BE63C3ABC3 for ; Tue, 13 May 2025 14:23:40 +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=13Lc63hGPrqKDFv0C7nKqUdQv5N1T5qxtfFNzi/6oZ4=; b=OVnZg+26X7kq2KV+/6OGQopmY7 uOhlzSAYThEhunec/ElcOkv2fQEl7isV+NVRvkf/pu5w+rP85SGuGKDN/+a2RaVqhZj8kZpb0Bprd gl6ZkuW0bNDF9mM74fXgtGYaO0gvOONluUzMTJsPMHT4yjZPhVYS4rRqlMUBm8/LMhmmlxhPy4HoZ NPE8KE4E0Diu4MhwahLTB+nWc8Q1wmKaaM8umh+uU8JwuMo3xFtj1VKSV5ZVe+tr02rdmWs7wmsGl ITX09IfIb0PuSoBjeVUyB2tRqMNec3DxBcwekIz/kdd7RhvIQdLApOYOxrScZJdCYYnwJthHHb+na sgnLWW7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uEqXc-0000000CbDB-0V2l; Tue, 13 May 2025 14:23:32 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uEqVW-0000000Cb67-27oi for linux-arm-kernel@lists.infradead.org; Tue, 13 May 2025 14:21:23 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 14FF15C6A3E; Tue, 13 May 2025 14:19:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46E6DC4CEE4; Tue, 13 May 2025 14:21:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747146081; bh=CleVcc0og0R0I/ZNcQtinsoFZO2oVo5dhJzV7xbtVzY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GnGZLGeoK7Asc4TqW1psqQgBMl7gMhbYoPXdf13r4wAcr5iwDyza+oM8gGEWjCG7/ 6AUW7ZVViM66GigZ0bW/6cXOkAGlciAU7nOYc/7zPdsIhLWPUuI5ATPzc2T54t1Ntb y/qzUPfVS+MTEb4D/99nupsyCP/Ha/nR1Psa8tt0TtXgSm5z0NTsomBdyiOQxWTa2u tOToARSU0tyPYT4zBADk5M8hPI8wXMfD53f4Hcq8PI8VHZ3bh7hMM+ziaiR0l1cLgY Kwm6WSar34DsACq+28Mo5jLyQEhN07TLy8pBoTpIaK2azW/P9A8f2bzIgKNi8kO7mG +76T5BeW7NvIw== Date: Tue, 13 May 2025 15:21:14 +0100 From: Will Deacon To: perlarsen@google.com Cc: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Sudeep Holla , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, sebastianene@google.com, lpieralisi@kernel.org, arve@android.com, qwandor@google.com, kernel-team@android.com, armellel@google.com, perl@immunant.com, jean-philippe@linaro.org, ahomescu@google.com, tabba@google.com, qperret@google.com, james.morse@arm.com Subject: Re: [PATCH v3 1/3] KVM: arm64: Restrict FF-A host version renegotiation Message-ID: <20250513142113.GA9443@willie-the-truck> References: <20250513-virtio-msg-ffa-v3-0-d66c76ff1b2c@google.com> <20250513-virtio-msg-ffa-v3-1-d66c76ff1b2c@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250513-virtio-msg-ffa-v3-1-d66c76ff1b2c@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250513_072122_589360_13C3CE91 X-CRM114-Status: GOOD ( 18.88 ) 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 Tue, May 13, 2025 at 06:28:30AM +0000, Per Larsen via B4 Relay wrote: > From: Per Larsen > > Prevent the host from re-negotiating a lesser minor version with the > hypervisor. Once the hypervisor negotiates a version, that should > remain locked in. Fix the current behaviour by returning NOT_SUPPORTED > to avoid the FF-A interoperability rules with lesser minor versions that > allow the host version to downgrade. > > Signed-off-by: Per Larsen > Signed-off-by: Per Larsen I'm not entirely sure why we need two SoB lines here... > arch/arm64/kvm/hyp/nvhe/ffa.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > index 3369dd0c4009f84ad3cf9481c747bdc57a162370..2c199d40811efb5bfae199c4a67d8ae3d9307357 100644 > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > @@ -712,7 +712,10 @@ static void do_ffa_version(struct arm_smccc_res *res, > > hyp_spin_lock(&version_lock); > if (has_version_negotiated) { > - res->a0 = hyp_ffa_version; > + if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_version)) > + res->a0 = FFA_RET_NOT_SUPPORTED; > + else > + res->a0 = hyp_ffa_version; > goto unlock; ... but the patch looks fine to me. Acked-by: Will Deacon Will