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 6F8D6CCFA03 for ; Thu, 6 Nov 2025 10:33:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vGxJ6-0005Tc-MV; Thu, 06 Nov 2025 05:33:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vGxJ5-0005Su-Ql for qemu-devel@nongnu.org; Thu, 06 Nov 2025 05:33:31 -0500 Received: from mail-yx1-xb12c.google.com ([2607:f8b0:4864:20::b12c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1vGxJ2-0004Ju-Iq for qemu-devel@nongnu.org; Thu, 06 Nov 2025 05:33:31 -0500 Received: by mail-yx1-xb12c.google.com with SMTP id 956f58d0204a3-63e336b1ac4so1091452d50.1 for ; Thu, 06 Nov 2025 02:33:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1762425207; x=1763030007; darn=nongnu.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=BvCHELAhMlngvHmdCqWKZIHEvGaRU5uQaDtuWSFHUIA=; b=DMVNjb5txrP//mSiK6Vrzli9UTbXRy8DOTp6n6+d18B9M2oCb1vHebbcOWSw34/E7j XApwDm5eLPeBWL4wDdSKk2oenf8sngArKkctpCp5BREQk3w8XKG+TR/jDOhSL076v7Ju bZAX2eYsFoK1iE/u+ZktmOkudDBVOnMqhG/XGuWexbXcwSeKR3oPu+i0H8kBVh1zi7uw 4dp5orTQZFS9JyGknWeKUH3vCbks4V4lt2ZsKgN7oMMxcI6NlrrGMsFZpXSZ6BWJAWwQ dFp+tA1izi85dckKmav9GzHYM2zclkpjAQEBq1Iwcx56WZ8jRaIVwjt7god184gJ+cmt u70w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762425207; x=1763030007; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=BvCHELAhMlngvHmdCqWKZIHEvGaRU5uQaDtuWSFHUIA=; b=msbBHcJ07IAnmSVbUjJQJ491F2OJqXcJzZtZ/joX+yXdsYhsmr8RJBryVydFB4/JWN RdgzCyGezToSpTTnnJ6/VO7utkMeygX0tMcNiens7cHipb6HDi+e+6bvP3YmKjyMeKNo hpF7OIoKgGT7CLB4U/qnIHB5vG84+3r9+2Dff5+1yZUdPiMrDIigMjBwq++0ZMgcMX5F jWhDJLqgG1SNbqRblvpY8UbRrvF9T2u9uFjoQcZTzOH1iWYnOdX2LyR3noTxLcRIJzz0 qoSfcNzyVwowt9fTeuYwEZfSw8ICpPBW9TPgZMLqThDOtUcgHTVVFQrHUIT1ZLQlv+/i gp1g== X-Forwarded-Encrypted: i=1; AJvYcCUEEtAxzhzawcuLLFLJpDV15c/voVBFN+Ycpvh2G/pSP44iwmWcODLN8PQGMGKSTr9Q0Q1K45JVyj2p@nongnu.org X-Gm-Message-State: AOJu0YxQPBeKZ23GcOJgHIAfTRtfPv+CF/FvOAuFqb5nBKO3NjO0Ofxw zcNCzWNItVcLoFAiZnAd5f3TeDKur0ykEobRPjA3Pm8g9mKqWYF2sexlgEAB7r9iMD+4x1ygDr2 5x+gTdeNfsM111b/MzdMdlLD8/U1HOs+2q9tsnFerYw== X-Gm-Gg: ASbGncufAi993uuZ44Rdzhjo7ULrKS38fUVVVtL4+AAOlzie+GD68Ii17w7HptKkYh7 /iWWZHsm6ncsCATJYKkPNsWJlxjZymLbQedPn3U1wOnAyiUm8BHuOsqDrcIjMM0S88xTdh2/hXf y/HihhqPrbPHGXo2FkxVEVZ9KE7TscuYvZDKl2bX27KJPOmit6m1N1eIaUh0uvf8NdAB99z6yVK tx79CNWZNp1atlCRCtn7sn0uJIEJYqtyTXdhzq5mKRkFqxgmPekuQx3SR3qxFhnx7C1/FK6 X-Google-Smtp-Source: AGHT+IEco8bLn1SdsB2OCkJpWIfdZBvI5/OErgSrP53wCT4iJ+XywXWMoNjSSasx+XgSBb/f9znUSYlrdFNoTdVV73w= X-Received: by 2002:a53:acce:0:20b0:63e:29af:bd23 with SMTP id 956f58d0204a3-640b53db810mr1707371d50.4.1762425206886; Thu, 06 Nov 2025 02:33:26 -0800 (PST) MIME-Version: 1.0 References: <20250129160059.6987-1-farosas@suse.de> <20250129160059.6987-8-farosas@suse.de> In-Reply-To: From: Peter Maydell Date: Thu, 6 Nov 2025 10:33:14 +0000 X-Gm-Features: AWmQ_bky7DlME38t5MRB4i-2-okJS38qIGD4aGOz9w08m0TIkT4Uj2JR_gJQALE Message-ID: Subject: Re: [PULL 07/42] machine: aux-ram-share option To: Peter Xu Cc: Fabiano Rosas , qemu-devel@nongnu.org, Steve Sistare Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::b12c; envelope-from=peter.maydell@linaro.org; helo=mail-yx1-xb12c.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, 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: 2.1.29 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, 5 Nov 2025 at 19:13, Peter Xu wrote: > > On Tue, Nov 04, 2025 at 10:53:54AM +0000, Peter Maydell wrote: > > On Wed, 29 Jan 2025 at 16:03, Fabiano Rosas wrote: > > > > > > From: Steve Sistare > > > > > > Allocate auxilliary guest RAM as an anonymous file that is shareable > > > with an external process. This option applies to memory allocated as > > > a side effect of creating various devices. It does not apply to > > > memory-backend-objects, whether explicitly specified on the command > > > line, or implicitly created by the -m command line option. > > > > > > This option is intended to support new migration modes, in which the > > > memory region can be transferred in place to a new QEMU process, by sending > > > the memfd file descriptor to the process. Memory contents are preserved, > > > and if the mode also transfers device descriptors, then pages that are > > > locked in memory for DMA remain locked. This behavior is a pre-requisite > > > for supporting vfio, vdpa, and iommufd devices with the new modes. > > > > Hi; I've just noticed that in this patch: > > > > > > > @@ -1162,6 +1178,12 @@ static void machine_class_init(ObjectClass *oc, void *data) > > > object_class_property_set_description(oc, "mem-merge", > > > "Enable/disable memory merge support"); > > > > > > +#ifdef CONFIG_POSIX > > > + object_class_property_add_bool(oc, "aux-ram-share", > > > + machine_get_aux_ram_share, > > > + machine_set_aux_ram_share); > > > +#endif > > > > we added a new class property to the machine, but we don't > > call object_class_property_set_description() to give it any > > help text (compare how we handle the other properties in this > > function). > > > > > + > > > object_class_property_add_bool(oc, "usb", > > > machine_get_usb, machine_set_usb); > > > object_class_property_set_description(oc, "usb", > > > > This means that if you run "qemu-system-x86_64 -M q35,help" > > you'll see that this option is missing help text: > > > > pc-q35-10.2-machine options: > > acpi= - Enable ACPI > > append= - Linux kernel command line > > aux-ram-share= > > boot= - Boot configuration > > bus-lock-ratelimit= - Set the ratelimit for the bus locks > > acquired in VMs > > confidential-guest-support=> - Set > > confidential guest scheme to support > > default-bus-bypass-iommu= > > [etc] > > > > Would somebody like to write a patch to add the missing > > description ? > > Thanks for reporting, sent "[PATCH] machine: Provide a description for > aux-ram-share property" just now. > > PS: for q35 there's another one fd-bootchk=.. Yes; it was looking at the bug report about that https://gitlab.com/qemu-project/qemu/-/issues/3193 that led me to spot the aux-ram-share option. -- PMM