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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C886BC433B4 for ; Thu, 8 Apr 2021 10:46:53 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 85C92610CA for ; Thu, 8 Apr 2021 10:46:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85C92610CA Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.107145.204795 (Exim 4.92) (envelope-from ) id 1lUSBF-0002Cm-DD; Thu, 08 Apr 2021 10:46:33 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 107145.204795; Thu, 08 Apr 2021 10:46:33 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lUSBF-0002Cf-A8; Thu, 08 Apr 2021 10:46:33 +0000 Received: by outflank-mailman (input) for mailman id 107145; Thu, 08 Apr 2021 10:46:31 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lUSBD-0002Ca-R2 for xen-devel@lists.xenproject.org; Thu, 08 Apr 2021 10:46:31 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id fad5d21f-5615-4327-b85a-f7fa0f1db9d5; Thu, 08 Apr 2021 10:46:30 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 02B79AF0C; Thu, 8 Apr 2021 10:46:30 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: fad5d21f-5615-4327-b85a-f7fa0f1db9d5 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1617878790; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6ZQUEv3YsWgUeNnzbHKfFcDKRbv7xchLw1z2v6sYugo=; b=g4q7YekVYuUKUf//Wz89zIwK7OfYkyXMxKed6hgXTQaS3nnwIc4+yeaaV0QmXvRkSCxwsa wgAvKWZAzdTQQwKLJ8Ro1W7lVYdcnXa269s2VP29lWWXMtUS8lzgVFXGpsniGDAylLBhEa 7JStoUadm3rJEV7/CHg5Gm387ZoRXJQ= Subject: Re: [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0 To: Luca Fancellu Cc: bertrand.marquis@arm.com, wei.chen@arm.com, Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Andrew Cooper , George Dunlap , Ian Jackson , Wei Liu , xen-devel@lists.xenproject.org References: <20210408094818.8173-1-luca.fancellu@arm.com> <20210408094818.8173-4-luca.fancellu@arm.com> From: Jan Beulich Message-ID: <19fd45ff-b373-dd89-9377-79cb77ffee5b@suse.com> Date: Thu, 8 Apr 2021 12:46:29 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: <20210408094818.8173-4-luca.fancellu@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 08.04.2021 11:48, Luca Fancellu wrote: > --- a/xen/common/domctl.c > +++ b/xen/common/domctl.c > @@ -419,7 +419,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl) > { > if ( dom == DOMID_FIRST_RESERVED ) > dom = 1; > - if ( is_free_domid(dom) ) > + if ( (dom != 0) && is_free_domid(dom) ) > break; > } > I don't think this change is needed - I don't see how dom could ever end up being zero. The code is already intended to be safe wrt accidentally creating a domain with ID zero. (Granted "rover" would benefit from being moved into the yet more narrow scope, which would make this even more obvious.) Jan