From nobody Tue Feb 10 05:41:15 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1505822582739225.39998791836933; Tue, 19 Sep 2017 05:03:02 -0700 (PDT) Received: from localhost ([::1]:42286 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1duHF0-000246-1S for importer@patchew.org; Tue, 19 Sep 2017 08:03:02 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40763) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1duHAq-0007Vw-5q for qemu-devel@nongnu.org; Tue, 19 Sep 2017 07:58:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1duHAn-00025r-5X for qemu-devel@nongnu.org; Tue, 19 Sep 2017 07:58:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50532) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1duHAn-00025c-0V for qemu-devel@nongnu.org; Tue, 19 Sep 2017 07:58:41 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 031D0C04B936; Tue, 19 Sep 2017 11:58:40 +0000 (UTC) Received: from localhost (ovpn-112-56.ams2.redhat.com [10.36.112.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id DE9CE600C2; Tue, 19 Sep 2017 11:58:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 031D0C04B936 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=marcandre.lureau@redhat.com From: marcandre.lureau@redhat.com To: linux-kernel@vger.kernel.org Date: Tue, 19 Sep 2017 13:58:14 +0200 Message-Id: <20170919115814.14724-5-marcandre.lureau@redhat.com> In-Reply-To: <20170919115814.14724-1-marcandre.lureau@redhat.com> References: <20170919115814.14724-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 19 Sep 2017 11:58:40 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 4/4] RFC: fw_cfg: add DMA write operation in sysfs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , somlo@cmu.edu, qemu-devel@nongnu.org, mst@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" From: Marc-Andr=C3=A9 Lureau Since qemu 2.9, DMA write operations are allowed. However, usage of this interface from kernel or user-space is strongly discouraged by the maintainers. This patch is meant for experimentations for now. Signed-off-by: Marc-Andr=C3=A9 Lureau --- drivers/firmware/qemu_fw_cfg.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c index 26152bfc7805..1ca3382e98df 100644 --- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -524,9 +524,28 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp= , struct kobject *kobj, return fw_cfg_read_blob(entry->f.select, buf, pos, count, true); } =20 +static ssize_t fw_cfg_sysfs_write_raw(struct file *filp, struct kobject *k= obj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct fw_cfg_sysfs_entry *entry =3D to_entry(kobj); + + if (!fw_cfg_dma_enabled()) + return -ENOTSUPP; + + if (pos > entry->f.size) + return -EINVAL; + + if (count > entry->f.size - pos) + count =3D entry->f.size - pos; + + return fw_cfg_write_blob(entry->f.select, buf, pos, count); +} + static struct bin_attribute fw_cfg_sysfs_attr_raw =3D { - .attr =3D { .name =3D "raw", .mode =3D S_IRUSR }, + .attr =3D { .name =3D "raw", .mode =3D S_IRUSR | S_IWUSR }, .read =3D fw_cfg_sysfs_read_raw, + .write =3D fw_cfg_sysfs_write_raw, }; =20 /* --=20 2.14.1.146.gd35faa819