From nobody Sun Dec 14 06:19:58 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 052E9C120; Tue, 13 May 2025 06:29:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747117741; cv=none; b=CSNhM4ou3xGibUGthQHtBcAI4T0+G8vlmpzytvFD8zeGExxKpV2OBWBtdLgNEZ5Cbasf+HE6c4vgNKj4RnSXY9yKb8IpYdBWZhAxRCqk40fYjbNY729cT9pTI49pY2l+1XwvO+4CDaCDiG1xjitFl5/AXgtHV2o5BGXmnWhtVfc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747117741; c=relaxed/simple; bh=CS2K4IBTS8BkewmPKf8FL6tLALwgWKThVfrXRfxYC+8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=MVTXPgKXzqHf1tPPZF1RAnB0YR0OBFRRldLf75hAJIQ8wH/zLDwRgHUw0lgiOH5o5eOvn4MQP7YxtFEWSHF2jKCLbWZndeqvHWWWG+KsYsMq/w68vTFT2M96CrffpssF0WnKtb+Y+7gc/XvzFZOt7SQyuL4WYZRDcqqU5jvX6mE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Dqm0UN82; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Dqm0UN82" Received: by smtp.kernel.org (Postfix) with ESMTPS id 81838C4CEED; Tue, 13 May 2025 06:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747117740; bh=CS2K4IBTS8BkewmPKf8FL6tLALwgWKThVfrXRfxYC+8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=Dqm0UN82QsfC4IQP/Cp66v3A1+Ww/WMaecVYDP4VjXCwpB3PAqxXIdYKQ31lj2bC6 g3YdR99MU4ZMe+Tc44aqWBGRC9BD5nq3a9N5tJ1poXYgvDqUrtUkHXRAaSt4nni0UF lP6psQWqFDko3jhH8QfJBioRZdbI1rZeX+geLEH930tpEIJchSBMQmGYux68a49iea SEC63Gqe5N2+Dzw9lF5Js+VMnOciEeOUbz/N6u+wP0oApZLxr54DcLfVehzik7RaNd WfMmzJaU+9h7VzMXD/maBUJuQ8UhUlsU6JXbEDnD7OJ6xkO6sQzpCRKv+B2T4jUwyB nE/lxI14+gryA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C62AC3ABD9; Tue, 13 May 2025 06:29:00 +0000 (UTC) From: Per Larsen via B4 Relay Date: Tue, 13 May 2025 06:28:30 +0000 Subject: [PATCH v3 1/3] KVM: arm64: Restrict FF-A host version renegotiation Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250513-virtio-msg-ffa-v3-1-d66c76ff1b2c@google.com> References: <20250513-virtio-msg-ffa-v3-0-d66c76ff1b2c@google.com> In-Reply-To: <20250513-virtio-msg-ffa-v3-0-d66c76ff1b2c@google.com> To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Sudeep Holla Cc: 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, Per Larsen X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1747117739; l=1163; i=perlarsen@google.com; s=20250508; h=from:subject:message-id; bh=Prs9vwH1PpI7boVTkM9t7dd2Gj6IXNMISFZbJ9u0HHQ=; b=iD3MoRDcl6vsNTRQcIKy81Aq/kHV0QjJvlLIp932eUrLbxYG5Q8loKlRusWWZDX7lgiC6r6kh mqLFZjkse+hA86wrqJ46kG7NDve/h1wBZyoRavVqXmupHV3UmqOlBhP X-Developer-Key: i=perlarsen@google.com; a=ed25519; pk=jjc/Ta4VmrLRmMoahP6d1mBcKzvWU+nsmdtYe2oS2kQ= X-Endpoint-Received: by B4 Relay for perlarsen@google.com/20250508 with auth_id=402 X-Original-From: Per Larsen Reply-To: perlarsen@google.com 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 Acked-by: Will Deacon --- 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..2c199d40811efb5bfae199c4a67= d8ae3d9307357 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, =20 hyp_spin_lock(&version_lock); if (has_version_negotiated) { - res->a0 =3D hyp_ffa_version; + if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_versi= on)) + res->a0 =3D FFA_RET_NOT_SUPPORTED; + else + res->a0 =3D hyp_ffa_version; goto unlock; } =20 --=20 2.49.0.1045.g170613ef41-goog