From nobody Wed Feb 11 05:35:54 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 683F838384 for ; Sun, 2 Mar 2025 14:34:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740926089; cv=none; b=YpW0ibBzed+icsuFnjx4ruEExG5a/JeICPgdDshxmzUq2LcCRMZPNtsnOxOvnoIQ7YhKhkYGY8DovPweiLQr0i5hkhqs/yHYInqmQ36R7nWqUqnCYaPC29hJoMgOf0swkj2khC8MA5Yy/PLwLF8xBl8YC184NO4w5ZZdo7Vwxuw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740926089; c=relaxed/simple; bh=3d1vy7K3Ewc6kBuoFdLtOj9nxEdW0vN1tk9jlWajiE4=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EZiC+5G2nnTq1jkCbVECr4LotyuAWqX3b+ofam6Dwy3kwc3W5RNeF8B6bGHY63e/eqPyoll7Xa+iGdFSTID3OxcklDYGiBTna4nNkjBzLYkJysQBh1LRv7rZhaxzqUNe/2JQB6+2T1h7k9H69XMkROk6FA1+R9Q89yUS+Vv23G8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=E7toa8nX; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="E7toa8nX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1740926085; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UZogOKk63vf4EDKHQk5Lj385qY5SA+Ws34nKuNOin7A=; b=E7toa8nXLSnlQxNM08jGdIlt8ZOTGBvEeKTYvVOGk0oHGWjOEqPO9VmpqkcD7tOse0rN18 j+jJ1IUEd7WWZMUFj3YERTH6gV3817VTia9foUO6CrR/2Fnln+Sxe+ypjMTUoTipwN18DZ 2EXiuViI+5+2kjiL1vAeRY6apun6ivs= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-86-dEq8IECyNwWicdQhcmOKLg-1; Sun, 02 Mar 2025 09:34:42 -0500 X-MC-Unique: dEq8IECyNwWicdQhcmOKLg-1 X-Mimecast-MFC-AGG-ID: dEq8IECyNwWicdQhcmOKLg_1740926081 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 599311800877; Sun, 2 Mar 2025 14:34:41 +0000 (UTC) Received: from server.redhat.com (unknown [10.72.112.49]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B62191956048; Sun, 2 Mar 2025 14:34:36 +0000 (UTC) From: Cindy Lu To: lulu@redhat.com, jasowang@redhat.com, mst@redhat.com, michael.christie@oracle.com, sgarzare@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH v7 8/8] vhost: Add a KConfig knob to enable IOCTL VHOST_FORK_FROM_OWNER Date: Sun, 2 Mar 2025 22:32:10 +0800 Message-ID: <20250302143259.1221569-9-lulu@redhat.com> In-Reply-To: <20250302143259.1221569-1-lulu@redhat.com> References: <20250302143259.1221569-1-lulu@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" Introduce a new config knob `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL`, to control the availability of the `VHOST_FORK_FROM_OWNER` ioctl. When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is set to n, the ioctl is disabled, and any attempt to use it will result in failure. Signed-off-by: Cindy Lu --- drivers/vhost/Kconfig | 15 +++++++++++++++ drivers/vhost/vhost.c | 11 +++++++++++ 2 files changed, 26 insertions(+) diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig index b455d9ab6f3d..e5b9dcbf31b6 100644 --- a/drivers/vhost/Kconfig +++ b/drivers/vhost/Kconfig @@ -95,3 +95,18 @@ config VHOST_CROSS_ENDIAN_LEGACY If unsure, say "N". =20 endif + +config VHOST_ENABLE_FORK_OWNER_IOCTL + bool "Enable IOCTL VHOST_FORK_FROM_OWNER" + default n + help + This option enables the IOCTL VHOST_FORK_FROM_OWNER, which allows + userspace applications to modify the thread mode for vhost devices. + + By default, `CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL` is set to `n`, + meaning the ioctl is disabled and any operation using this ioctl + will fail. + When the configuration is enabled (y), the ioctl becomes + available, allowing users to set the mode if needed. + + If unsure, say "N". diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index fb0c7fb43f78..09e5e44dc516 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2294,6 +2294,8 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned in= t ioctl, void __user *argp) r =3D vhost_dev_set_owner(d); goto done; } + +#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL if (ioctl =3D=3D VHOST_FORK_FROM_OWNER) { u8 inherit_owner; /*inherit_owner can only be modified before owner is set*/ @@ -2313,6 +2315,15 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned i= nt ioctl, void __user *argp) r =3D 0; goto done; } + +#else + if (ioctl =3D=3D VHOST_FORK_FROM_OWNER) { + /* When CONFIG_VHOST_ENABLE_FORK_OWNER_IOCTL is 'n', return error */ + r =3D -ENOTTY; + goto done; + } +#endif + /* You must be the owner to do anything else */ r =3D vhost_dev_check_owner(d); if (r) --=20 2.45.0