From nobody Sun Feb 8 16:31:08 2026 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 6D4A62620CA; Thu, 8 May 2025 08:39:32 +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=1746693572; cv=none; b=PcQPeG0TB99OFtLzyooFvqel5H5tdEVRV2HIH/4HEKVv2lRoQnMSHBUSA2c/ianexfUFOuoVP5nl0eFCg1KW80l0/j+VcEuBHhxhYWnSneqFEJNfVy7dGvnde1SCpgpROL8kYqvWJg/J/5VEePDdW0QZWTRMtM2qa1zwhoYJAvo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746693572; c=relaxed/simple; bh=yuBweLnXJr+UlHoAeP0Vp5rW+zBWTBXlDB/S+fvgixg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=FXxI7fQo27Mh4JB/mJ6fw2yO5A9TmXf//fcBVyawzHFFDPmvQfhc445mSHzsM+fXtLC5hkf5mZVkwgvbtZROyd+kInONGZmnqumHZ5V3hX9+nEW6PThuyrbSNerMIOEkM39rJGmY5fYAyT2/VtrNm0K4lEJ17mDJEplaaEKW9DA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RCaXU2yy; 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="RCaXU2yy" Received: by smtp.kernel.org (Postfix) with ESMTPS id EDA60C4CEEF; Thu, 8 May 2025 08:39:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746693572; bh=yuBweLnXJr+UlHoAeP0Vp5rW+zBWTBXlDB/S+fvgixg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=RCaXU2yy1eGr0Ao8jVrCf4FS/Gj9dHBIGZOoYtF7QleJaVWX6f56MtZ37Pm4IYJI6 f97zAssJjYoRHFLmeIoqktFp7zrtbtgBHa1b5ADak76G58xUiK7w/Tm/6TSWHAABPe w5C5NkJYTrPOFsj/gbcEYSFh94VuY8xK+PvpNNL8PyyjvyYwrzxEhgABkatyxIidBs +08EvAJpyQi+JSdZJxT7uUoZKnO/+WXsqYDkjAAEPSTzEMfJTJkmJM6fwZ8prS35e1 3HLmpyS4PQVUT6OWHRYqsJReDWM+iue4WFnQyDevQpW2FtAmDD+ypVG5O/ySMWUkk/ 56L+6dgyFQEfw== 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 DA856C3ABC5; Thu, 8 May 2025 08:39:31 +0000 (UTC) From: Per Larsen via B4 Relay Date: Thu, 08 May 2025 08:38:52 +0000 Subject: [PATCH v2 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: <20250508-virtio-msg-ffa-v2-1-ed84f8053965@google.com> References: <20250508-virtio-msg-ffa-v2-0-ed84f8053965@google.com> In-Reply-To: <20250508-virtio-msg-ffa-v2-0-ed84f8053965@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, arve@android.com, lpieralisi@kernel.org, qwandor@google.com, jean-philippe@linaro.org, james.morse@arm.com, perl@immunant.com, tabba@google.com, kernel-team@android.com, armellel@google.com, qperret@google.com, sebastianene@google.com, ahomescu@google.com, Per Larsen X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1746693571; l=1162; i=perlarsen@google.com; s=20250508; h=from:subject:message-id; bh=J3MWSM5x2/SDttpy5fJekCrept6pUn9foVmr8XHfbVs=; b=Tg7dgit3kVDTUX65R4PhEXNXxB3lmCZRYexlRi3hD5jNmaUMG4KAbKfgshhUz94xxl0AsCRLm EkblOHMrR3rCekrYx3uolLaOoJxg+OaWEnz+RuGNqykxMOnI9X5gOAm 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 --- 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 2.49.0.987.g0cc8ee98dc-goog