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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 09CE7C433B4 for ; Mon, 17 May 2021 09:38:08 +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 B809B611CA for ; Mon, 17 May 2021 09:38:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B809B611CA 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.128138.240615 (Exim 4.92) (envelope-from ) id 1liZhH-0007lu-4Z; Mon, 17 May 2021 09:37:59 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 128138.240615; Mon, 17 May 2021 09:37:59 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1liZhH-0007ln-1h; Mon, 17 May 2021 09:37:59 +0000 Received: by outflank-mailman (input) for mailman id 128138; Mon, 17 May 2021 09:37:58 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1liZhG-0007lR-40 for xen-devel@lists.xenproject.org; Mon, 17 May 2021 09:37:58 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 49b7c9ea-3462-4fcf-b705-60f99bbd78f1; Mon, 17 May 2021 09:37:57 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A9039B179; Mon, 17 May 2021 09:37:56 +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: 49b7c9ea-3462-4fcf-b705-60f99bbd78f1 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=1621244276; 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=cupozExXSDEk2x6F4/kVlSk0FfTDS14py9FNXF+6+qY=; b=JwPk3ZUf5cV6QirZEXyDbEucNXJPmCQDyoElMNdcFu5z8Aq6Nw9ANdW+BcIM7Gcxwhd1gM Mg5wzs7HCj2rydCJjGCg8uqIrlO4+/RNtE0jHTkJnEm33rsgspndz0VghOgyRLswAo5zsB dk5oXo7kbT5z2Sq1YNHkOwDPDFb4f+w= Subject: Re: [PATCH] include/public: add RING_RESPONSE_PROD_OVERFLOW macro To: Juergen Gross References: <20210512164800.26236-1-jgross@suse.com> Cc: xen-devel@lists.xenproject.org From: Jan Beulich Message-ID: <26985871-d70d-2184-c27e-fe161127de5f@suse.com> Date: Mon, 17 May 2021 11:38:04 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210512164800.26236-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 12.05.2021 18:48, Juergen Gross wrote: > Add a new RING_RESPONSE_PROD_OVERFLOW() macro for being able to > detect an ill-behaved backend tampering with the response producer > index. > > Signed-off-by: Juergen Gross Acked-by: Jan Beulich > --- a/xen/include/public/io/ring.h > +++ b/xen/include/public/io/ring.h > @@ -259,6 +259,10 @@ typedef struct __name##_back_ring __name##_back_ring_t > #define RING_REQUEST_PROD_OVERFLOW(_r, _prod) \ > (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r)) > > +/* Ill-behaved backend determination: Can there be this many responses? */ > +#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod) \ > + (((_prod) - (_r)->rsp_cons) > RING_SIZE(_r)) > + > #define RING_PUSH_REQUESTS(_r) do { \ > xen_wmb(); /* back sees requests /before/ updated producer index */ \ > (_r)->sring->req_prod = (_r)->req_prod_pvt; \ >