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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3BB1EECAAD3 for ; Mon, 5 Sep 2022 13:42:51 +0000 (UTC) Received: from localhost ([::1]:56448 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVCNG-0003SY-3G for qemu-devel@archiver.kernel.org; Mon, 05 Sep 2022 09:42:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44704) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVCLr-0002ZZ-CH for qemu-devel@nongnu.org; Mon, 05 Sep 2022 09:41:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:22014) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVCLn-0001S9-0i for qemu-devel@nongnu.org; Mon, 05 Sep 2022 09:41:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662385277; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kT+DQZyNNMNjZTrXAXT7SPEFcnJH0LmHyTJ3JZkM9VA=; b=X5JB7i64KIvcWdIBrbgHuVBSpH8Conk2OPz9nQtLxY55KE4yxzMjyanv7tdsEYR/P8kADB /HKFrDGjgEwRyetnvmIEmEHKjM7L7/n44MsT4g5kdgUuS+sDQemEjvH7vXClD0j+Vv7e43 p/pg7/ZVTylr5jhxFm3gtRfTMNFp2qg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-223-Ws8tfkRJOBy13MIaAD8dXA-1; Mon, 05 Sep 2022 09:41:16 -0400 X-MC-Unique: Ws8tfkRJOBy13MIaAD8dXA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DA6CD10395C1; Mon, 5 Sep 2022 13:41:15 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.166]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 841342166B26; Mon, 5 Sep 2022 13:41:15 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 31CED21E6900; Mon, 5 Sep 2022 15:41:13 +0200 (CEST) From: Markus Armbruster To: Daniel Henrique Barboza Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, clg@kaod.org, "Dr . David Alan Gilbert" , Markus Armbruster , Alistair Francis , David Gibson Subject: Re: [PATCH v6 14/14] qmp/hmp, device_tree.c: introduce dumpdtb References: <20220904233456.209027-1-danielhb413@gmail.com> <20220904233456.209027-15-danielhb413@gmail.com> Date: Mon, 05 Sep 2022 15:41:13 +0200 In-Reply-To: <20220904233456.209027-15-danielhb413@gmail.com> (Daniel Henrique Barboza's message of "Sun, 4 Sep 2022 20:34:56 -0300") Message-ID: <87edwqhrba.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Daniel Henrique Barboza writes: > To save the FDT blob we have the '-machine dumpdtb=' property. > With this property set, the machine saves the FDT in and exit. > The created file can then be converted to plain text dts format using > 'dtc'. > > There's nothing particularly sophisticated into saving the FDT that > can't be done with the machine at any state, as long as the machine has > a valid FDT to be saved. > > The 'dumpdtb' command receives a 'filename' paramenter and, if a valid > FDT is available, it'll save it in a file 'filename'. In short, this is > a '-machine dumpdtb' that can be fired on demand via QMP/HMP. > > A valid FDT consists of a FDT that was created using libfdt being > retrieved via 'current_machine->fdt' in device_tree.c. This condition is > met by most FDT users in QEMU. > > This command will always be executed in-band (i.e. holding BQL), > avoiding potential race conditions with machines that might change the > FDT during runtime (e.g. PowerPC 'pseries' machine). > > Cc: Dr. David Alan Gilbert > Cc: Markus Armbruster > Cc: Alistair Francis > Cc: David Gibson > Signed-off-by: Daniel Henrique Barboza > --- > hmp-commands.hx | 15 +++++++++++++++ > include/sysemu/device_tree.h | 1 + > monitor/misc.c | 1 + > qapi/machine.json | 18 ++++++++++++++++++ > softmmu/device_tree.c | 31 +++++++++++++++++++++++++++++++ > 5 files changed, 66 insertions(+) > > diff --git a/hmp-commands.hx b/hmp-commands.hx > index 182e639d14..9a3e57504f 100644 > --- a/hmp-commands.hx > +++ b/hmp-commands.hx > @@ -1800,3 +1800,18 @@ ERST > "\n\t\t\t\t\t limit on a specified virtual cpu", > .cmd = hmp_cancel_vcpu_dirty_limit, > }, > + > +#if defined(CONFIG_FDT) > +SRST > +``dumpdtb`` *filename* > + Save the FDT in the 'filename' file to be decoded using dtc. > + Requires 'libfdt' support. Does the #if suppress the documentation snippet when !defined(CONFIG_FDT)? If yes, the "Requires" line is redundant. Other conditional commands don't have such lines. > +ERST > + { > + .name = "dumpdtb", > + .args_type = "filename:F", > + .params = "filename", > + .help = "save the FDT in the 'filename' file to be decoded using dtc", > + .cmd = hmp_dumpdtb, > + }, > +#endif > diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h > index ef060a9759..e7c5441f56 100644 > --- a/include/sysemu/device_tree.h > +++ b/include/sysemu/device_tree.h > @@ -136,6 +136,7 @@ int qemu_fdt_add_path(void *fdt, const char *path); > } while (0) > > void qemu_fdt_dumpdtb(void *fdt, int size); > +void hmp_dumpdtb(Monitor *mon, const QDict *qdict); > > /** > * qemu_fdt_setprop_sized_cells_from_array: > diff --git a/monitor/misc.c b/monitor/misc.c > index 3d2312ba8d..e7dd63030b 100644 > --- a/monitor/misc.c > +++ b/monitor/misc.c > @@ -49,6 +49,7 @@ > #include "sysemu/blockdev.h" > #include "sysemu/sysemu.h" > #include "sysemu/tpm.h" > +#include "sysemu/device_tree.h" > #include "qapi/qmp/qdict.h" > #include "qapi/qmp/qerror.h" > #include "qapi/qmp/qstring.h" > diff --git a/qapi/machine.json b/qapi/machine.json > index 6afd1936b0..f968a5d343 100644 > --- a/qapi/machine.json > +++ b/qapi/machine.json > @@ -1664,3 +1664,21 @@ > '*size': 'size', > '*max-size': 'size', > '*slots': 'uint64' } } > + > +## > +# @dumpdtb: > +# > +# Save the FDT in dtb format. Requires 'libfdt' support. We rarely document conditionals like this. It's kind of redundant with the If CONFIG_FDT part in the generated documentation. Aside: this "If" part could certainly be improved. > +# > +# @filename: name of the FDT file to be created > +# > +# Since: 7.2 > +# > +# Example: > +# {"execute": "dumpdtb"} > +# "arguments": { "filename": "/tmp/fdt.dtb" } } Excuse my nitpicking... Creating files with a fixed filename in /tmp is a bad habit, and this example promotes it. We have similar examples elsewhere. Still, I'd prefer not to add more. > +# > +## > +{ 'command': 'dumpdtb', > + 'data': { 'filename': 'str' }, > + 'if': 'CONFIG_FDT' } > diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c > index 6ca3fad285..cdd41b6de6 100644 > --- a/softmmu/device_tree.c > +++ b/softmmu/device_tree.c > @@ -26,6 +26,9 @@ > #include "hw/loader.h" > #include "hw/boards.h" > #include "qemu/config-file.h" > +#include "qapi/qapi-commands-machine.h" > +#include "qapi/qmp/qdict.h" > +#include "monitor/hmp.h" > > #include > > @@ -643,3 +646,31 @@ out: > g_free(propcells); > return ret; > } > + > +void qmp_dumpdtb(const char *filename, Error **errp) > +{ > + g_autoptr(GError) err = NULL; > + int size; > + > + if (!current_machine->fdt) { > + error_setg(errp, "Unable to find the machine FDT"); Perhaps: "this machine doesn't have an FDT". > + return; > + } > + > + size = fdt_totalsize(current_machine->fdt); > + > + if (!g_file_set_contents(filename, current_machine->fdt, size, &err)) { > + error_setg(errp, "Error saving FDT to file %s: %s", > + filename, err->message); > + } > +} > + > +void hmp_dumpdtb(Monitor *mon, const QDict *qdict) > +{ > + const char *filename = qdict_get_str(qdict, "filename"); > + Error *local_err = NULL; > + > + qmp_dumpdtb(filename, &local_err); > + > + hmp_handle_error(mon, local_err); > +}