From nobody Mon Feb 9 03:33:26 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 E7990238159; Fri, 16 May 2025 12:14:10 +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=1747397651; cv=none; b=hzvUnw/qrHr6ElrCfxNK79I9XwmXdiX1/gxZ/Xc+DqQLYRyD7fv7H8BlwvLrIMnoXlc35gE8emPsdLefhj/3rwYUMVaOT9WdFvke2Dq7+CVgdPsekxHG37+lvez7qKrTnaK2L2GLyf4TRGC37663/qwQIKOU9Bl3SQjckvDtZ/g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747397651; c=relaxed/simple; bh=/lGfEK9zU2R6gaBuqIOJeoWF1339hPhixjeue3QgP5o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=P7kJIusgfCBonaugu6iQigdvY/0s61iC4gb4NE7fKOQrYQHap32vy11/mpeXtSk+EmrNTFGuxqSY79WnJ+CfKkqBKNebeEOoqXqKPJd38tUetwbr7ReyHPNQXuFYKItykGYLRGEkX1Cpgp9/xKpY1pXCtjBqnFMQgYY2nb0DWaU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dbMC5gGK; 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="dbMC5gGK" Received: by smtp.kernel.org (Postfix) with ESMTPS id B8C78C4CEEB; Fri, 16 May 2025 12:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747397650; bh=/lGfEK9zU2R6gaBuqIOJeoWF1339hPhixjeue3QgP5o=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=dbMC5gGKFmMSORqwk1vfo9RNP992blX2U+MtZhiFH0ZBTH4MwmBnf3smKSjRzdNbo nujshAmCrXxBQcWrow3owAlU854/VsrBKy9vvhAHlecQZogET+TaMMpRbt+FVYyj76 er5nodp0v8i/Tq+3/EYIGZV2+3b9Cq5D6+39xg6+QP3I8b5zEthRzd/omD9lMuVqdd vy5I7Szstaok1mMmuU3wrMOlMe5AjzVlivc54oZesUbuey9/nk0DNmcju5xyTgyDGX 1PScCs8ufZFbYT6pGdDvuNHRnecFd5sxFu8rWE04hcSeqAMAy9LDZtRwlWHM01/oYR yttLZu/itLtPA== 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 A4C67C3ABD8; Fri, 16 May 2025 12:14:10 +0000 (UTC) From: Per Larsen via B4 Relay Date: Fri, 16 May 2025 12:14:00 +0000 Subject: [PATCH v4 1/5] 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: <20250516-virtio-msg-ffa-v4-1-580ee70e5081@google.com> References: <20250516-virtio-msg-ffa-v4-0-580ee70e5081@google.com> In-Reply-To: <20250516-virtio-msg-ffa-v4-0-580ee70e5081@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, qperret@google.com, qwandor@google.com, arve@android.com, perl@immunant.com, lpieralisi@kernel.org, kernel-team@android.com, tabba@google.com, james.morse@arm.com, armellel@google.com, jean-philippe@linaro.org, ahomescu@google.com, Per Larsen X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1747397650; l=1116; i=perlarsen@google.com; s=20250508; h=from:subject:message-id; bh=KE0l+d+r+QSm1fqDkNHRHhbIpv9VyyzBoa1V1b9tCZk=; b=LpJQ30mDqqHwDjaicF57PfEsiV7MpwOBSa0ddOhXxE84Qd3wunEL4UivPaPq6LT+HD2GHuv3p j+jb5zbBL7OCb+5b7E/fOyA9HFK3/8f8HvTAypL/tv+h04OrdDwtmbL 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 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 2.49.0.1101.gccaa498523-goog