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 7A8B9C433ED for ; Wed, 14 Apr 2021 07:09:09 +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 33498613A9 for ; Wed, 14 Apr 2021 07:09:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33498613A9 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.110291.210525 (Exim 4.92) (envelope-from ) id 1lWZdx-0003Wk-Cy; Wed, 14 Apr 2021 07:08:57 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 110291.210525; Wed, 14 Apr 2021 07:08:57 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWZdx-0003Wd-9k; Wed, 14 Apr 2021 07:08:57 +0000 Received: by outflank-mailman (input) for mailman id 110291; Wed, 14 Apr 2021 07:08:55 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWZdv-0003WY-OA for xen-devel@lists.xenproject.org; Wed, 14 Apr 2021 07:08:55 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 3edbe01e-fd5c-449c-86bc-4c78dda82757; Wed, 14 Apr 2021 07:08:54 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 092C6ABF6; Wed, 14 Apr 2021 07:08:54 +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: 3edbe01e-fd5c-449c-86bc-4c78dda82757 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=1618384134; 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=RiFrZyUPfSjBNn4B9b7ANfZDAeDCAhfH65U6rhgfmbI=; b=G4uLbLZXs0Tjk8cckPDDjnzNtZMjKFWxT0lUa9I9A7ZjobfWQx4i3HGSnV+20ghRUYJCxo i8Dmi5ZbrbwQaPIaUfKR7bhiZDzpucO2cpHIekgxJzNM0nxA3Ma/tpqV698giuhyjlJANB QuKN+eXBnYWGcCGky556p9A02V4Xju8= Subject: Re: [PATCH v2] xen/pci: Refactor PCI MSI interrupts related code To: Julien Grall Cc: xen-devel@lists.xenproject.org, bertrand.marquis@arm.com, Andrew Cooper , Wei Liu , George Dunlap , Ian Jackson , Stefano Stabellini , Paul Durrant , Volodymyr Babchuk , Daniel De Graaf , Rahul Singh , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: From: Jan Beulich Message-ID: Date: Wed, 14 Apr 2021 09:08:53 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 13.04.2021 19:12, Julien Grall wrote: > On 12/04/2021 11:49, Roger Pau Monné wrote: >> On Fri, Apr 09, 2021 at 05:00:41PM +0100, Rahul Singh wrote: >>> --- a/xen/include/xen/vpci.h >>> +++ b/xen/include/xen/vpci.h >>> @@ -91,6 +91,7 @@ struct vpci { >>> /* FIXME: currently there's no support for SR-IOV. */ >>> } header; >>> >>> +#ifdef CONFIG_PCI_MSI_INTERCEPT >>> /* MSI data. */ >>> struct vpci_msi { >>> /* Address. */ >>> @@ -136,6 +137,7 @@ struct vpci { >>> struct vpci_arch_msix_entry arch; >>> } entries[]; >>> } *msix; >>> +#endif /* CONFIG_PCI_MSI_INTERCEPT */ >> >> Note that here you just remove two pointers from the struct, not that >> I'm opposed to it, but it's not that much space that's saved anyway. >> Ie: it might also be fine to just leave them as NULL unconditionally >> on Arm. > > Can the two pointers be NULL on x86? If not, then I would prefer if they > disappear on Arm so there is less chance to make any mistake (such as > unconditionally accessing the pointer in common code). Alternative proposal: How about making it effectively impossible to de-reference the pointer on Arm by leaving the field there, but having the struct definition available on non-Arm only? Jan