From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BD41C433E0 for ; Mon, 22 Jun 2020 14:11:13 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9151E206E2 for ; Mon, 22 Jun 2020 14:11:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="AZ9DPD+L" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9151E206E2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47142 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jnNAF-0007p6-KE for qemu-devel@archiver.kernel.org; Mon, 22 Jun 2020 10:11:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33288) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jnN7n-00059t-T7 for qemu-devel@nongnu.org; Mon, 22 Jun 2020 10:08:39 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:28866 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jnN7l-0001Zx-R2 for qemu-devel@nongnu.org; Mon, 22 Jun 2020 10:08:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592834917; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ziMa7Evr9YzbGBPs7fpJYrt8/CdgEp11GNeVLcr7h7Y=; b=AZ9DPD+LSo+sYffLjGv/cZoeimWGnYkE62LP5pc6RWs+BQJwuzsCYGVvPX8RkIeWYvzSww U6khx1WVWr1m3CbJIpvkMuMJ6L6RoGP1bbtpeAQxQ0JCyp/FsLx9gXzqowEUksP9wdMM23 c83MBTlDICAjsgpMFuez0M5pszdaOYc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-57-MQKTZgRuOtqGU71CswvfXg-1; Mon, 22 Jun 2020 10:08:25 -0400 X-MC-Unique: MQKTZgRuOtqGU71CswvfXg-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3CB1F107ACF3 for ; Mon, 22 Jun 2020 14:08:24 +0000 (UTC) Received: from redhat.com (unknown [10.36.110.63]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E0F371671; Mon, 22 Jun 2020 14:08:17 +0000 (UTC) Date: Mon, 22 Jun 2020 15:08:14 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v9 1/5] hw/nvram/fw_cfg: Add the FW_CFG_DATA_GENERATOR interface Message-ID: <20200622140814.GI736373@redhat.com> References: <20200615103457.25282-1-philmd@redhat.com> <20200615103457.25282-2-philmd@redhat.com> <20200616153122.GN550360@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.0 (2020-05-02) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.120; envelope-from=berrange@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/22 02:57:26 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Paolo Bonzini , Laszlo Ersek , qemu-devel@nongnu.org, Gerd Hoffmann Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jun 22, 2020 at 03:54:58PM +0200, Philippe Mathieu-Daudé wrote: > On 6/16/20 5:31 PM, Daniel P. Berrangé wrote: > > On Mon, Jun 15, 2020 at 12:34:53PM +0200, Philippe Mathieu-Daudé wrote: > >> The FW_CFG_DATA_GENERATOR allows any object to produce > >> blob of data consumable by the fw_cfg device. > >> > >> Reviewed-by: Laszlo Ersek > >> Signed-off-by: Philippe Mathieu-Daudé > >> --- > >> docs/specs/fw_cfg.txt | 9 ++++++- > >> include/hw/nvram/fw_cfg.h | 52 +++++++++++++++++++++++++++++++++++++++ > >> hw/nvram/fw_cfg.c | 36 +++++++++++++++++++++++++++ > >> 3 files changed, 96 insertions(+), 1 deletion(-) > >> > >> diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt > >> index 8f1ebc66fa..bc16daa38a 100644 > >> --- a/docs/specs/fw_cfg.txt > >> +++ b/docs/specs/fw_cfg.txt > >> @@ -219,7 +219,7 @@ To check the result, read the "control" field: > >> > >> = Externally Provided Items = > >> > >> -As of v2.4, "file" fw_cfg items (i.e., items with selector keys above > >> +Since v2.4, "file" fw_cfg items (i.e., items with selector keys above > >> FW_CFG_FILE_FIRST, and with a corresponding entry in the fw_cfg file > >> directory structure) may be inserted via the QEMU command line, using > >> the following syntax: > >> @@ -230,6 +230,13 @@ Or > >> > >> -fw_cfg [name=],string= > >> > >> +Since v5.1, QEMU allows some objects to generate fw_cfg-specific content, > >> +the content is then associated with a "file" item using the 'gen_id' option > >> +in the command line, using the following syntax: > >> + > >> + -object ,id=,[generator-specific-options] \ > >> + -fw_cfg [name=],gen_id= > >> + > >> See QEMU man page for more documentation. > >> > >> Using item_name with plain ASCII characters only is recommended. > >> diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h > >> index 25d9307018..ca69666847 100644 > >> --- a/include/hw/nvram/fw_cfg.h > >> +++ b/include/hw/nvram/fw_cfg.h > >> @@ -9,11 +9,43 @@ > >> #define TYPE_FW_CFG "fw_cfg" > >> #define TYPE_FW_CFG_IO "fw_cfg_io" > >> #define TYPE_FW_CFG_MEM "fw_cfg_mem" > >> +#define TYPE_FW_CFG_DATA_GENERATOR_INTERFACE "fw_cfg-data-generator" > >> > >> #define FW_CFG(obj) OBJECT_CHECK(FWCfgState, (obj), TYPE_FW_CFG) > >> #define FW_CFG_IO(obj) OBJECT_CHECK(FWCfgIoState, (obj), TYPE_FW_CFG_IO) > >> #define FW_CFG_MEM(obj) OBJECT_CHECK(FWCfgMemState, (obj), TYPE_FW_CFG_MEM) > >> > >> +#define FW_CFG_DATA_GENERATOR_CLASS(class) \ > >> + OBJECT_CLASS_CHECK(FWCfgDataGeneratorClass, (class), \ > >> + TYPE_FW_CFG_DATA_GENERATOR_INTERFACE) > >> +#define FW_CFG_DATA_GENERATOR_GET_CLASS(obj) \ > >> + OBJECT_GET_CLASS(FWCfgDataGeneratorClass, (obj), \ > >> + TYPE_FW_CFG_DATA_GENERATOR_INTERFACE) > >> + > >> +typedef struct FWCfgDataGeneratorClass { > >> + /*< private >*/ > >> + InterfaceClass parent_class; > >> + /*< public >*/ > >> + > >> + /** > >> + * get_data: > >> + * @obj: the object implementing this interface > >> + * > >> + * Returns: pointer to start of the generated item data > >> + * > >> + * The returned pointer is a QObject weak reference, @obj owns > >> + * the reference and may free it at any time in the future. > > > > This description is a bit odd. We're just returning a plain byte > > array pointer, not a QObject, nor a reference, not will it be > > free'd at any time. > > > >> + */ > >> + const void *(*get_data)(Object *obj); > >> + /** > >> + * get_length: > >> + * @obj: the object implementing this interface > >> + * > >> + * Returns: the size of the generated item data in bytes > >> + */ > >> + size_t (*get_length)(Object *obj); > > > > I'd be inclined to have a single method that returns a GByteArray, > > instead of separate methods for data & length. > > > > That gives you a sized byte array, with a well define lifetime, > > which is what the caller really wants here. ie > > > > /** > > * get_data: > > * @obj: the object implementing this interface > > * > > * Returns: reference to a byte array containing the data. > > * The caller should release the reference when no longer > > * required. > > */ > > GByteArray *(*get_data)(Object *obj); > > > >> +} FWCfgDataGeneratorClass; > >> + > > > > .... > > > > > >> +size_t fw_cfg_add_from_generator(FWCfgState *s, const char *filename, > >> + const char *gen_id, Error **errp) > >> +{ > >> + FWCfgDataGeneratorClass *klass; > >> + Object *obj; > >> + size_t size; > >> + > >> + obj = object_resolve_path_component(object_get_objects_root(), gen_id); > >> + if (!obj) { > >> + error_setg(errp, "Cannot find object ID '%s'", gen_id); > >> + return 0; > >> + } > >> + if (!object_dynamic_cast(obj, TYPE_FW_CFG_DATA_GENERATOR_INTERFACE)) { > >> + error_setg(errp, "Object ID '%s' is not a '%s' subclass", > >> + gen_id, TYPE_FW_CFG_DATA_GENERATOR_INTERFACE); > >> + return 0; > >> + } > >> + klass = FW_CFG_DATA_GENERATOR_GET_CLASS(obj); > > > > ...then the following: > > > >> + size = klass->get_length(obj); > >> + if (size == 0) { > >> + error_setg(errp, "Object ID '%s' failed to generate fw_cfg data", > >> + gen_id); > >> + return 0; > >> + } > >> + fw_cfg_add_file(s, filename, g_memdup(klass->get_data(obj), (guint)size), > >> + size); > > > > Can be replaced with: > > > > g_autoptr(GByteArray) data = klass->get_data(obj); > > > > fw_cfg_add_file(s, filename, g_byte_array_steal(data, NULL), > > (guint)g_byte_array_get_size(data)); > > g_byte_array_steal() has been added in GLib 2.64, > QEMU supports up to 2.48. > > I guess I have to use g_byte_array_free_to_bytes() > and g_memdup(g_bytes_get_data()) to achieve something > similar. I'll try. Or can possibly use the simpler g_byte_array_free and avoid the g_autoptr Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|