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 C29FE10A62DA for ; Thu, 26 Mar 2026 14:23:49 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1w5lcN-0001q3-H9; Thu, 26 Mar 2026 10:23:27 -0400 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 1w5lcM-0001oe-Cj for qemu-devel@nongnu.org; Thu, 26 Mar 2026 10:23:26 -0400 Received: from v512.v5f06b487.use4.send.mailgun.net ([143.55.232.12]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1w5lcK-0007Fq-Uw for qemu-devel@nongnu.org; Thu, 26 Mar 2026 10:23:26 -0400 X-Mailgun-Sid: WyI4ZDFlNiIsInFlbXUtZGV2ZWxAbm9uZ251Lm9yZyIsIjk3NjA3ZSJd Received: from mail.yodel.dev (mail.yodel.dev [35.209.39.246]) by 4672c174be1b1dddd4b896e00e537c8606a2d15c795bb35a340774dab9ba4457 with SMTP id 69c5415a35e5318eb8c58b96; Thu, 26 Mar 2026 14:23:22 GMT X-Mailgun-Sending-Ip: 143.55.232.12 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yodel.dev; s=rsa2048; t=1774535001; bh=7/nGmhoH3sKOLJwyqqBuCyO5NaRJ714yeRSKynUoLeo=; h=Message-ID:Date:MIME-Version:Subject:To:References:X-Mailgun-Dkim: From:In-Reply-To:Content-Type:Content-Transfer-Encoding:From: Reply-to:Subject:Date:Message-id:To:Cc:Mime-version:Content-type: Content-transfer-encoding:In-reply-to:References; b=l12Uvc+/fOw+mBrH/JMlGTK+c3FZBoeN5zxbqt1xl7H99pR71EVJQ3QybviRCpyNT gaJL6QqgNh87NoEbUtf46dzlhmIObB2okd1cvQkq7hYWm81sZtC7MrP8Hr8hTHvo1T 0Ve00zWqs4evCe0Ze0NFGi6L3pVfRniA/thIttD8F/jx7+avn4VhasWnMFArEqN32o MrsoZ0hCblCy1IZaY4uHrblI1Ww6a5BLolcqqezKxDNAkABSBqw0MDkbAvjAJcYA4J UkwA33XoxLWqCXGabLl3Z3w/XTZxWWIiyTLCBf6YGdZL5bh56xxBhg5UaDt0jqRdTx l7ZAj4PfIb23Q== Message-ID: <5c3050df-20a9-4e58-b918-7ce503313780@yodel.dev> Date: Thu, 26 Mar 2026 09:23:21 -0500 MIME-Version: 1.0 Subject: Re: [PATCH 03/15] hw/alpha/dp264: Validate kernel and initrd sizes To: Richard Henderson , qemu-devel@nongnu.org References: <20260310-qomify-alpha-v1-0-4375b00a85ff@yodel.dev> <20260310-qomify-alpha-v1-3-4375b00a85ff@yodel.dev> <979d9029-c49b-4bdd-823c-ca356d63a1c3@linaro.org> <7cd87657-f7fc-41c5-bdde-a5e6c5bf1399@yodel.dev> <614e25b5-74e1-4620-947a-3c92ed6f2a9f@linaro.org> Content-Language: en-US X-Mailgun-Dkim: no X-Mailgun-Dkim: no From: Yodel Eldar Autocrypt: addr=yodel.eldar@yodel.dev; keydata= xjMEZxqXdhYJKwYBBAHaRw8BAQdAkletQdG3CLyANZyuf2t7Z9PK4b6HiT+DdSPUB2mHzmPN I1lvZGVsIEVsZGFyIDx5b2RlbC5lbGRhckB5b2RlbC5kZXY+wpkEExYKAEECGwMFCQOcG00F CwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQTTzRjNQG27imap+N+V7k+3NmVNrAUCaNWASwIZ AQAKCRCV7k+3NmVNrNnSAPoDjQXa6v7ZzdQSaLdRfAQy/5SsUucv+zp3WAP4pXdgJQEAzMMC Ctx4l6b13Fs2hZdRXEnF/4BZ9t1K68nwzZOV3QnOOARnGpd2EgorBgEEAZdVAQUBAQdAKPIy 3W/DKFsm1e+31zoqmOY0pqz8vjIM846wM6lEY2QDAQgHwn4EGBYIACYCGwwWIQTTzRjNQG27 imap+N+V7k+3NmVNrAUCaNWG7QUJA5wi9wAKCRCV7k+3NmVNrPusAQCQDQwETy7VT6UhHPho TkrQnsNqQfFU3tXqCTiViToktQD7B/U2/to97hQIJCWbK6yd3T+KPZJPMcHMg2XRyedUvgA= In-Reply-To: <614e25b5-74e1-4620-947a-3c92ed6f2a9f@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=143.55.232.12; envelope-from=bounce+0e9322.97607e-qemu-devel=nongnu.org@yodel.dev; helo=v512.v5f06b487.use4.send.mailgun.net 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, HELO_STATIC_HOST=-0.001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: qemu development 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 25/03/2026 22:07, Richard Henderson wrote: > On 3/26/26 12:04, Yodel Eldar wrote: >> Hi, Richard >> >> On 25/03/2026 19:11, Richard Henderson wrote: >>> On 3/11/26 08:31, Yodel Eldar wrote: >>>> @@ -192,7 +192,15 @@ static void clipper_init(MachineState *machine) >>>>               } >>>>               /* Put the initrd image as high in memory as >>>> possible.  */ >>>> -            initrd_base = (ram_size - initrd_size) & TARGET_PAGE_MASK; >>>> +            if (usub64_overflow(ram_size, initrd_size, >>>> &initrd_base)) { >>>> +                error_report("initial ram disk exceeds allotted ram >>>> size"); >>>> +                exit(1); >>>> +            } >>>> +            initrd_base &= TARGET_PAGE_MASK; >>>> +            if (initrd_base <= kernel_high) { >>>> +                warn_report("initial ram disk overlaps with kernel"); >>>> +            } >>> >>> Why is the first an error and the second a warning? >>> >> >> Initially, I had both as fatal, but then I figured a (mis)adventurous >> user may actually want to experiment with kernel/initrd overlap, whereas >> an underflow is something we can't allow (and initrd being larger than >> RAM is physically impossible AFAIK). I could make the overlap fatal, >> too, if that's better? > > I can't see it being useful at all. > Heh, fair enough; fatal, it is, then. Thanks, Yodel > > r~ >