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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 0714EC433B4 for ; Thu, 8 Apr 2021 10:50:12 +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 A943E6113A for ; Thu, 8 Apr 2021 10:50:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A943E6113A 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.107156.204823 (Exim 4.92) (envelope-from ) id 1lUSEM-0002T7-DH; Thu, 08 Apr 2021 10:49:46 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 107156.204823; Thu, 08 Apr 2021 10:49:46 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lUSEM-0002T0-9q; Thu, 08 Apr 2021 10:49:46 +0000 Received: by outflank-mailman (input) for mailman id 107156; Thu, 08 Apr 2021 10:49:45 +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 1lUSEL-0002Su-Mw for xen-devel@lists.xenproject.org; Thu, 08 Apr 2021 10:49:45 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 0119987e-cca5-4929-b0d0-574aa3b1fca9; Thu, 08 Apr 2021 10:49:44 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 2EFF8AFC9; Thu, 8 Apr 2021 10:49:44 +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: 0119987e-cca5-4929-b0d0-574aa3b1fca9 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=1617878984; 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=Vz6RoCr0dlx61kH31AEPM56hEpZxmmmxVsgrvGqqQ2c=; b=ltw05bjqi3sbf57jjHokkO2sMF3h5Ssz5yZmo+/1aTxgJwwKE31VsUeaIbCYfhgHizZRP4 gTcLc/cWPiei7tHKhP3nqWLldPrwLZ7OQkDv49kS3+Sqt2x+sMNDVhK5MkFU++Gq+fm4z5 o+Y1v1v630St5rj/H3KQh1v1xDcWRaY= Subject: Re: [PATCH v3 03/11] x86/vlapic: introduce an EOI callback mechanism To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Andrew Cooper , Wei Liu , xen-devel@lists.xenproject.org References: <20210331103303.79705-1-roger.pau@citrix.com> <20210331103303.79705-4-roger.pau@citrix.com> From: Jan Beulich Message-ID: <9ef5ce06-051f-6f05-613e-82612d02f8e0@suse.com> Date: Thu, 8 Apr 2021 12:49:44 +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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 08.04.2021 11:12, Roger Pau Monné wrote: > On Thu, Apr 08, 2021 at 08:20:15AM +0200, Jan Beulich wrote: >> On 07.04.2021 18:27, Roger Pau Monné wrote: >>> On Wed, Apr 07, 2021 at 04:55:43PM +0200, Jan Beulich wrote: >>>> On 31.03.2021 12:32, Roger Pau Monne wrote: >>>>> Add a new vlapic_set_irq_callback helper in order to inject a vector >>>>> and set a callback to be executed when the guest performs the end of >>>>> interrupt acknowledgment. >>>>> >>>>> Such functionality will be used to migrate the current ad hoc handling >>>>> done in vlapic_handle_EOI for the vectors that require some logic to >>>>> be executed when the end of interrupt is performed. >>>>> >>>>> The setter of the callback will be in charge for setting the callback >>>>> again on resume. That is the reason why vlapic_set_callback is not a >>>>> static function. >>>> >>>> I'm struggling with your use of "resume" here: Resuming from S3 >>>> doesn't require re-doing anything that's kept in memory, does it? >>>> So what meaning does the word have here? >>> >>> Right, I can see the confusion. Resume here means a guest being >>> migrated or restored, not Xen itself being resumed. Callbacks are not >>> part of the exported guest state, and hence any emulated device that >>> requires a callback will have to register it as part of loading the >>> saved state. >>> >>>> Apart from this, and with the xzalloc_array() change requested >>>> by Andrew, this looks good to me. >> >> In which case with this change and "resume" replaced suitably in the >> description > > I've worded it as: > > "The setter of the callback will be in charge for setting the callback > again on guest restore or resume, as callbacks are not saved as part > of the vlapic state. That is the reason why vlapic_set_callback is not > a static function." Hmm, you still mention "resume", which makes me continue to wonder what you're thinking of beyond guest restore. Jan