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 31824C433DB for ; Fri, 15 Jan 2021 10:49:43 +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 DB91722583 for ; Fri, 15 Jan 2021 10:49:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB91722583 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.67923.121431 (Exim 4.92) (envelope-from ) id 1l0Mfe-0000cu-Bj; Fri, 15 Jan 2021 10:49:34 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 67923.121431; Fri, 15 Jan 2021 10:49:34 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l0Mfe-0000cn-7x; Fri, 15 Jan 2021 10:49:34 +0000 Received: by outflank-mailman (input) for mailman id 67923; Fri, 15 Jan 2021 10:49:33 +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 1l0Mfd-0000ci-Ad for xen-devel@lists.xenproject.org; Fri, 15 Jan 2021 10:49:33 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id c06370fd-f475-44e6-b9af-069de3da8329; Fri, 15 Jan 2021 10:49:32 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id ADAA4B7C6; Fri, 15 Jan 2021 10:49:31 +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: c06370fd-f475-44e6-b9af-069de3da8329 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=1610707771; 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=0wbW9SfgCP7l8fLzfZHftbtusH8Rh0iD+i7SWjYtVCQ=; b=XQh3o3urooe0vus1aQEY5jPBXEBlJlMvlAT6jiwswstbwmJ2F9VU/9jqa+UZ4gWK12e9Av 5V0+VXI4gOBUpkWOfOyOmmyLxcCY0+MJuee1gTpOpSuorQ5BUXvvc9TfzvgweJGjI4IK4Z FDQR8TTn3rgHWekz2QR+wAK/pJxpiZs= Subject: Re: [PATCH] common: don't require use of DOMID_SELF To: Andrew Cooper Cc: George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu , "xen-devel@lists.xenproject.org" References: <72c9f0ec-81e3-63f9-2513-46e463642219@suse.com> <3c0ebca6-a5e9-36a8-cfeb-6abc0fc7c2af@citrix.com> From: Jan Beulich Message-ID: <7e714873-8fa6-269c-d6c4-806a74046ef9@suse.com> Date: Fri, 15 Jan 2021 11:49:32 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <3c0ebca6-a5e9-36a8-cfeb-6abc0fc7c2af@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 14.01.2021 16:01, Andrew Cooper wrote: > On 14/01/2021 14:02, Jan Beulich wrote: >> --- a/xen/common/page_alloc.c >> +++ b/xen/common/page_alloc.c >> @@ -2566,13 +2566,7 @@ __initcall(register_heap_trigger); >> >> struct domain *get_pg_owner(domid_t domid) >> { >> - struct domain *pg_owner = NULL, *curr = current->domain; >> - >> - if ( unlikely(domid == curr->domain_id) ) >> - { >> - gdprintk(XENLOG_WARNING, "Cannot specify itself as foreign domain\n"); >> - goto out; >> - } >> + struct domain *pg_owner; > > I'm not sure this is correct. > > It isn't a DOMID_SELF check.  It's a "confirm the nominated domid is > remote" check, and I don't see all the callers of this interface having > appropriate checks to prohibit trying to do a foreign operation on > oneself, however they specify the foreign domid. Since Julien had me look up all the call sites anyway (for adding respective commentary in the public headers), I checked this property as well: The only case where a foreign domain is strictly required is the handling of XENMAPSPACE_gmfn_foreign, and there a respective check exists. I actually question do_mmuext_op()'s use of the function, as neither DOMID_IO nor DOMID_XEN ought to be sensibly usable there. Jan