From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:55408) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hDtKU-0001x2-4E for qemu-devel@nongnu.org; Tue, 09 Apr 2019 12:10:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hDtKS-0004Ql-7t for qemu-devel@nongnu.org; Tue, 09 Apr 2019 12:10:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1942) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hDtKQ-0004Hs-J0 for qemu-devel@nongnu.org; Tue, 09 Apr 2019 12:10:31 -0400 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Tue, 9 Apr 2019 18:09:49 +0200 Message-Id: <20190409161009.6322-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v4 00/20] monitor: add asynchronous command type List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Eric Blake , Markus Armbruster , "Dr. David Alan Gilbert" , Gerd Hoffmann , Michael Roth , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Hi, HMP and QMP commands are handled synchronously in qemu today. But there are benefits allowing the command handler to re-enter the main loop if the command cannot be handled synchronously, or if it is long-lasting. Some bugs such as rhbz#1230527 are difficult to solve without it. The common solution is to use a pair of command+event in this case. But this approach has a number of issues: - you can't "fix" an existing command: you need a new API, and ad-hoc documentation for that command+signal association, and old/broken command deprecation - since the reply event is broadcasted and 'id' is used for matching the request, it may conflict with other clients request 'id' space - it is arguably less efficient and elegant (weird API, useless return in most cases, broadcast reply, no cancelling on disconnect etc) The following series implements an async command solution instead. By introducing a session context and a command return handler, it can: - defer the return, allowing the mainloop to reenter - return only to the caller (instead of broadcast events for reply) - optionnally allow cancellation when the client is gone - track on-going qapi command(s) per client/session and without introduction of new QMP APIs or client visible change. Existing qemu commands can be gradually replaced by async:true variants when needed, while carefully reviewing the concurrency aspects. The async:true commands marshaller helpers are splitted in half, the calling and return functions. The command is called with a QmpReturn context, that can return immediately or later, using the generated return helper, which allows for a step-by-step conversion. The screendump command is converted to an async:true version to solve rhbz#1230527. The command shows basic cancellation (this could be extended if needed). It could be further improved to do asynchronous IO writes as well. v4: - rebased, mostly adapting to new OOB code (there was not much feedback in v3 for the async command part, but preliminary patches got merged!) - drop the RFC status v3: - complete rework, dropping the asynchronous commands visibility from the protocol side entirely (until there is a real need for it) - rebased, with a few preliminary cleanup patches - teach asynchronous commands to HMP v2: - documentation fixes and improvements - fix calling async commands sync without id - fix bad hmp monitor assert - add a few extra asserts - add async with no-id failure and screendump test Marc-Andr=C3=A9 Lureau (20): qmp: constify QmpCommand and list json-lexer: make it safe to call destroy multiple times qmp: add QmpSession QmpSession: add a return callback QmpSession: add json parser and use it in qga monitor: use qmp session to parse json feed qga: simplify dispatch_return_cb QmpSession: introduce QmpReturn qmp: simplify qmp_return_error() QmpSession: keep a queue of pending commands QmpSession: return orderly qmp: introduce asynchronous command type scripts: learn 'async' qapi commands qmp: add qmp_return_is_cancelled() monitor: add qmp_return_get_monitor() console: add graphic_hw_update_done() console: make screendump asynchronous monitor: start making qmp_human_monitor_command() asynchronous monitor: teach HMP about asynchronous commands hmp: call the asynchronous QMP screendump to fix outdated/glitches qapi/misc.json | 3 +- qapi/ui.json | 3 +- scripts/qapi/commands.py | 151 ++++++++++++++--- scripts/qapi/common.py | 15 +- scripts/qapi/doc.py | 3 +- scripts/qapi/introspect.py | 3 +- hmp.h | 3 +- include/monitor/monitor.h | 3 + include/qapi/qmp/dispatch.h | 89 +++++++++- include/qapi/qmp/json-parser.h | 7 +- include/ui/console.h | 5 + hmp.c | 6 +- hw/display/qxl-render.c | 9 +- hw/display/qxl.c | 1 + monitor.c | 198 ++++++++++++++-------- qapi/qmp-dispatch.c | 214 +++++++++++++++++++----- qapi/qmp-registry.c | 33 +++- qga/commands.c | 2 +- qga/main.c | 51 ++---- qobject/json-lexer.c | 5 +- qobject/json-streamer.c | 3 +- tests/test-qmp-cmds.c | 206 +++++++++++++++++++---- ui/console.c | 100 +++++++++-- hmp-commands.hx | 3 +- tests/qapi-schema/qapi-schema-test.json | 5 + tests/qapi-schema/qapi-schema-test.out | 8 + tests/qapi-schema/test-qapi.py | 8 +- 27 files changed, 877 insertions(+), 260 deletions(-) --=20 2.21.0.196.g041f5ea1cf 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=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 635B0C282CE for ; 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Tue, 09 Apr 2019 12:10:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1942) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hDtKQ-0004Hs-J0 for qemu-devel@nongnu.org; Tue, 09 Apr 2019 12:10:31 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AEE44307CB59; Tue, 9 Apr 2019 16:10:15 +0000 (UTC) Received: from localhost (ovpn-112-27.ams2.redhat.com [10.36.112.27]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9432726333; Tue, 9 Apr 2019 16:10:10 +0000 (UTC) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= To: qemu-devel@nongnu.org Date: Tue, 9 Apr 2019 18:09:49 +0200 Message-Id: <20190409161009.6322-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 09 Apr 2019 16:10:15 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4 00/20] monitor: add asynchronous command type 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: Michael Roth , Markus Armbruster , Gerd Hoffmann , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190409160949.YOAqAIjipA9aSS8kelj7995GeRUc1-7IQ9WCZRr2iyA@z> Hi, HMP and QMP commands are handled synchronously in qemu today. But there are benefits allowing the command handler to re-enter the main loop if the command cannot be handled synchronously, or if it is long-lasting. Some bugs such as rhbz#1230527 are difficult to solve without it. The common solution is to use a pair of command+event in this case. But this approach has a number of issues: - you can't "fix" an existing command: you need a new API, and ad-hoc documentation for that command+signal association, and old/broken command deprecation - since the reply event is broadcasted and 'id' is used for matching the request, it may conflict with other clients request 'id' space - it is arguably less efficient and elegant (weird API, useless return in most cases, broadcast reply, no cancelling on disconnect etc) The following series implements an async command solution instead. By introducing a session context and a command return handler, it can: - defer the return, allowing the mainloop to reenter - return only to the caller (instead of broadcast events for reply) - optionnally allow cancellation when the client is gone - track on-going qapi command(s) per client/session and without introduction of new QMP APIs or client visible change. Existing qemu commands can be gradually replaced by async:true variants when needed, while carefully reviewing the concurrency aspects. The async:true commands marshaller helpers are splitted in half, the calling and return functions. The command is called with a QmpReturn context, that can return immediately or later, using the generated return helper, which allows for a step-by-step conversion. The screendump command is converted to an async:true version to solve rhbz#1230527. The command shows basic cancellation (this could be extended if needed). It could be further improved to do asynchronous IO writes as well. v4: - rebased, mostly adapting to new OOB code (there was not much feedback in v3 for the async command part, but preliminary patches got merged!) - drop the RFC status v3: - complete rework, dropping the asynchronous commands visibility from the protocol side entirely (until there is a real need for it) - rebased, with a few preliminary cleanup patches - teach asynchronous commands to HMP v2: - documentation fixes and improvements - fix calling async commands sync without id - fix bad hmp monitor assert - add a few extra asserts - add async with no-id failure and screendump test Marc-Andr=C3=A9 Lureau (20): qmp: constify QmpCommand and list json-lexer: make it safe to call destroy multiple times qmp: add QmpSession QmpSession: add a return callback QmpSession: add json parser and use it in qga monitor: use qmp session to parse json feed qga: simplify dispatch_return_cb QmpSession: introduce QmpReturn qmp: simplify qmp_return_error() QmpSession: keep a queue of pending commands QmpSession: return orderly qmp: introduce asynchronous command type scripts: learn 'async' qapi commands qmp: add qmp_return_is_cancelled() monitor: add qmp_return_get_monitor() console: add graphic_hw_update_done() console: make screendump asynchronous monitor: start making qmp_human_monitor_command() asynchronous monitor: teach HMP about asynchronous commands hmp: call the asynchronous QMP screendump to fix outdated/glitches qapi/misc.json | 3 +- qapi/ui.json | 3 +- scripts/qapi/commands.py | 151 ++++++++++++++--- scripts/qapi/common.py | 15 +- scripts/qapi/doc.py | 3 +- scripts/qapi/introspect.py | 3 +- hmp.h | 3 +- include/monitor/monitor.h | 3 + include/qapi/qmp/dispatch.h | 89 +++++++++- include/qapi/qmp/json-parser.h | 7 +- include/ui/console.h | 5 + hmp.c | 6 +- hw/display/qxl-render.c | 9 +- hw/display/qxl.c | 1 + monitor.c | 198 ++++++++++++++-------- qapi/qmp-dispatch.c | 214 +++++++++++++++++++----- qapi/qmp-registry.c | 33 +++- qga/commands.c | 2 +- qga/main.c | 51 ++---- qobject/json-lexer.c | 5 +- qobject/json-streamer.c | 3 +- tests/test-qmp-cmds.c | 206 +++++++++++++++++++---- ui/console.c | 100 +++++++++-- hmp-commands.hx | 3 +- tests/qapi-schema/qapi-schema-test.json | 5 + tests/qapi-schema/qapi-schema-test.out | 8 + tests/qapi-schema/test-qapi.py | 8 +- 27 files changed, 877 insertions(+), 260 deletions(-) --=20 2.21.0.196.g041f5ea1cf