From patchwork Mon Jun 15 18:45:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gabriel L. Somlo" X-Patchwork-Id: 484499 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 398ED14032B for ; Tue, 16 Jun 2015 04:46:16 +1000 (AEST) Received: from localhost ([::1]:36022 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4ZOf-0007f6-UY for incoming@patchwork.ozlabs.org; Mon, 15 Jun 2015 14:46:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40429) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4ZOM-0007NW-O6 for qemu-devel@nongnu.org; Mon, 15 Jun 2015 14:45:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4ZOH-0002KJ-NX for qemu-devel@nongnu.org; Mon, 15 Jun 2015 14:45:54 -0400 Received: from relay-06.andrew.cmu.edu ([128.2.157.21]:46418 helo=relay.andrew.cmu.edu) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4ZOH-0002Ed-J0 for qemu-devel@nongnu.org; Mon, 15 Jun 2015 14:45:49 -0400 Received: from HEDWIG.ini.cmu.edu (HEDWIG.INI.CMU.EDU [128.2.16.51]) by relay.andrew.cmu.edu (8.14.8/8.14.8) with ESMTP id t5FIjlIv006786; Mon, 15 Jun 2015 14:45:47 -0400 From: "Gabriel L. Somlo" To: qemu-devel@nongnu.org Date: Mon, 15 Jun 2015 14:45:47 -0400 Message-Id: <1434393947-2622-1-git-send-email-somlo@cmu.edu> X-Mailer: git-send-email 2.1.0 X-Scanned-By: MIMEDefang 2.74 on 128.2.157.21 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x X-Received-From: 128.2.157.21 Cc: gsomlo@gmail.com, kraxel@redhat.com Subject: [Qemu-devel] [PATCH] fw_cfg: document fw_cfg_modify_iXX() update functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Document the behavior of fw_cfg_modify_iXX() for leak-less updating of integer-type blobs. Currently only fw_cfg_modify_i16() is coded, but 32- and 64-bit versions may be added later if necessary.. Signed-off-by: Gabriel Somlo --- docs/specs/fw_cfg.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 74351dd..5bc7b96 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -159,6 +159,17 @@ will convert a 16-, 32-, or 64-bit integer to little-endian, then add a dynamically allocated copy of the appropriately sized item to fw_cfg under the given selector key value. +== fw_cfg_modify_iXX() == + +Modify the value of an XX-bit item (where XX may be 16, 32, or 64). +Similarly to the corresponding fw_cfg_add_iXX() function set, convert +a 16-, 32-, or 64-bit integer to little endian, create a dynamically +allocated copy of the required size, and replace the existing item at +the given selector key value with the newly allocated one. The previous +item, assumed to have been allocated during an earlier call to +fw_cfg_add_iXX() or fw_cfg_modify_iXX() (of the same width XX), is freed +before the function returns. + == fw_cfg_add_file() == Given a filename (i.e., fw_cfg item name), starting pointer, and size,