From nobody Mon Dec 15 23:38:52 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 BDF5B2FE386; Tue, 1 Jul 2025 22:06:47 +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=1751407607; cv=none; b=Q9xb0eVSdBZ9Ja+ghtPVq0eOaKjs3Ex/6QU0isieniU7YWslbjEaGpKEn56+5l1LN0VHYGb+wRfqH31Y4Ml/VtUaYoQzPVVmrFXEXOUKhfsZGTNBs1bqY2yTnubThyS+NqrY0kzfPJmoMXquuia+3w7BiDYIowwTNlLLInQDS48= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751407607; c=relaxed/simple; bh=coAKO9TLhK8MTIgf77yLemsOevi3hPcTUAqXS91Y2b4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qLeNxqTHDJDik8BKW+gIkp0C146jGw6sXc4ixJEtXneotUaJ86IhUo9777+lrW/x6zjra7mW82F1Z8FzWoXal0GTkMb5Rl8BYaey8lhG/7T4bOtuO7Z5OZB9j6C7Z7lWD5pFz0eRRxC4cCQ1DOwFQgPmMb7+Qqdk7eI3P0Hdufs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ou9N1VQW; 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="ou9N1VQW" Received: by smtp.kernel.org (Postfix) with ESMTPS id 6688AC4CEF3; Tue, 1 Jul 2025 22:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751407607; bh=coAKO9TLhK8MTIgf77yLemsOevi3hPcTUAqXS91Y2b4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=ou9N1VQWEpWqTJgnCNRhMvXIzHw+LyYwPmDO37rQ0wuMJYADInvEcSP7RvEEPV/Hv mVqafQKIUYfwd+DySyV4CkmOKFysZAppyNhCCyaW9eDiZRCLpJhfgKSPqrYYhfYsTR /7BVBY/MaGyayNxtNwxudldX73TfASMmOL6567TXwhrtYAOsfHvQWnwBMAFNdSfiKK AMWosxvMUEo6svrC0FM8qEiNOB11a6HiTt2O/s+26rztwzSVpZP618MK8p9vbU4OP+ Om5/EQ8pF8Q+ZsvRT9xtmLam1uNeiEwWs4onSDsdnQ7/i9G80Me0aAUuQ+dF49n2B2 0caV0cTO9jN4A== 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 54480C8303D; Tue, 1 Jul 2025 22:06:47 +0000 (UTC) From: Per Larsen via B4 Relay Date: Tue, 01 Jul 2025 22:06:34 +0000 Subject: [PATCH v7 1/5] KVM: arm64: Correct return value on host version downgrade attempt 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: <20250701-virtio-msg-ffa-v7-1-995afc3d385e@google.com> References: <20250701-virtio-msg-ffa-v7-0-995afc3d385e@google.com> In-Reply-To: <20250701-virtio-msg-ffa-v7-0-995afc3d385e@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, ahomescu@google.com, armellel@google.com, arve@android.com, ayrton@google.com, qperret@google.com, sebastianene@google.com, qwandor@google.com, Per Larsen X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1751407606; l=1399; i=perlarsen@google.com; s=20250508; h=from:subject:message-id; bh=Dl9KrxrUP4K0W3dgejUfrC3aK93wdcqeauIVLeuo9f0=; b=5+AIZdXIIvjP+RFQX4/gsaepjpoFaUB3whIL6rjGFeBYlFyAuLRkoOvgzhSwRQhsyy388yIym 3qKnZpyTKsYCmPGQlh0pIPCa2Xcoa7Q6uUDbGY9Mzwew3tvIgMN7r6E 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 Once the hypervisor negotiates the FF-A version with the host, it should remain locked-in. However, it is possible to load FF-A as a module first supporting version 1.1 and then 1.0. Without this patch, the FF-A 1.0 driver will use 1.0 data structures to make calls which the hypervisor will incorrectly interpret as 1.1 data structures. With this patch, negotiation will fail. This patch does not change existing functionality in the case where a FF-A 1.2 driver is loaded after a 1.1 driver; the 1.2 driver will need to use 1.1 in order to proceed. Acked-by: Will Deacon 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 2.50.0.727.gbf7dc18ff4-goog