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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 03848C433ED for ; Fri, 16 Apr 2021 09:53:56 +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 563536115B for ; Fri, 16 Apr 2021 09:53:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 563536115B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45776 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lXLAg-0006QC-1D for qemu-devel@archiver.kernel.org; Fri, 16 Apr 2021 05:53:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48826) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXL9D-0005uc-4x for qemu-devel@nongnu.org; Fri, 16 Apr 2021 05:52:23 -0400 Received: from mail-vs1-xe2d.google.com ([2607:f8b0:4864:20::e2d]:45728) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lXL9A-0001RX-Tt for qemu-devel@nongnu.org; Fri, 16 Apr 2021 05:52:22 -0400 Received: by mail-vs1-xe2d.google.com with SMTP id r18so7737687vso.12 for ; Fri, 16 Apr 2021 02:52:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=hX8EXsNF2qrRQCqZyoWi9S8IFc6cCC7TLO4ay8lK7RM=; b=Mnp8vu93AmTvppCGkDchuP87aNGMHiwHhjhzM3VB54e7WBPvORv3wOkKfYIJi8ZODl yp5mk5W+4t/vp5cyTeHtrwmaqPP9T7QKYzTKsTcB3GBxNLNbu6RpQyG+GeOc+rhrDeSP mABpibXhWlQEDxrfUNsTjbt7i0/6vUKykZFwDIjtKvDWwIk3wT8qyrjVQ9IPUYnWCP3p 0IjEJYhUL4JrjzeoB5yuPFZHxN2Dx6GT57WmqQEa6sLN/q/5Z4mzqCyi8DaIAc7h1e6y raVPIRFOqv6YBtAOY/z257bPn7ZWV7CSHELx8EGPb6amEBqdHNRCiFbW11lnhRhoLp7g sC2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=hX8EXsNF2qrRQCqZyoWi9S8IFc6cCC7TLO4ay8lK7RM=; b=dgLjzN50ZwxfWfaeuH/OjnD2T51iK48kgf/jKg3ktZFOotabRbigkc9VavBYqwiTJw OrnlreKYSOGWPnrK4orN5SjefLTq35sILYFDpMQ4Qfm0OpaFJ4FS9anniWwry0dlbdJi AKbTpB88xI1LMNfiJ2EFKanlR006ruuYi8J7kRGPPdK78ATBS8j/5JbyVc1vS+vsSnYG cgQTCnJz0a254MTnejk6QBHH2IYVwYRYzH2WaToqEe7ZLGAdmskYPxnsnIbxlSXZ6F0T vBfATh5URMNv0i2mQ3MDtvNglUcfGmKQoQcomJbqhTtnHh7waLBtaR+pzMZ0owN85Bbp sstA== X-Gm-Message-State: AOAM530fVx3Xf7UYHqPgsDUBMA6BLY/20PW2+/w2bu4Rli1irokipdqV M7Nfpyhtno9myPeqPKpkhFS2MSmQ+NcUrAb0NPM= X-Google-Smtp-Source: ABdhPJwaQZS4QdTr06OoylDdpgz9k7VNce4MLBEttr5UQKkEykyHtQifiKdLlkAzEvEsVh0ledZtQDDmIttu/9gLK0o= X-Received: by 2002:a05:6102:ed0:: with SMTP id m16mr5923650vst.4.1618566739939; Fri, 16 Apr 2021 02:52:19 -0700 (PDT) MIME-Version: 1.0 References: <20210315170636.704201-1-zhlcindy@gmail.com> <20210315170636.704201-2-zhlcindy@gmail.com> <8735vu1ybo.fsf@dusky.pond.sub.org> <87a6py7evm.fsf@dusky.pond.sub.org> In-Reply-To: <87a6py7evm.fsf@dusky.pond.sub.org> From: Li Zhang Date: Fri, 16 Apr 2021 11:52:09 +0200 Message-ID: Subject: Re: [PATCH 2/2] Support monitor chardev hotswap with QMP To: Markus Armbruster Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::e2d; envelope-from=zhlcindy@gmail.com; helo=mail-vs1-xe2d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: , Cc: lukasstraub2@web.de, alexandr.iarygin@profitbricks.com, qemu-devel@nongnu.org, Li Zhang , pankaj.gupta@cloud.ionos.com, marcandre.lureau@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When I tried chardev-change, it reports this error: { "error": { "class": "GenericError", "desc": "Chardev user does not support chardev hotswap" } } On Fri, Apr 16, 2021 at 11:33 AM Markus Armbruster wrote: > > Li Zhang writes: > > > On Tue, Apr 13, 2021 at 8:41 AM Markus Armbruster wrote: > >> > >> Li Zhang writes: > >> > >> > From: Li Zhang > >> > > >> > For some scenarios, it needs to hot-add a monitor device. > >> > But QEMU doesn't support hotplug yet. It also works by adding > >> > a monitor with null backend by default and then change its > >> > backend to socket by QMP command "chardev-change". > >> > > >> > So this patch is to support monitor chardev hotswap with QMP. > >> > > >> > Signed-off-by: Li Zhang > >> > >> I think what what you're trying to say is that chardev-change does not > >> work when the character device changes is used by a QMP monitor. > >> Correct? > >> > > I mean that when the character device is a monitor device, it doesn't > > work with a QMP monitor. > > For example, I add 2 QMP monitors and change one of the monitor's > > backends from socket to a null device. > > It doesn't work because it needs the monitor device to support chardev-change. > > > >> If yes, how exactly does it misbehave? > > This command chardev-change needs specific device's change callback function. > > Yes, but what happens if you try anyway? I'm asking, because I'd like > the answer to be worked into the commit message. > > >> Does it work with an HMP monitor? > > No, it doesn't work. > -- Best Regards -Li