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 48936C63777 for ; Fri, 20 Nov 2020 09:00:13 +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 AB25C2224C for ; Fri, 20 Nov 2020 09:00:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Wzg80ch2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB25C2224C 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.31780.62452 (Exim 4.92) (envelope-from ) id 1kg2Gt-0007Nu-AB; Fri, 20 Nov 2020 08:59:59 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 31780.62452; Fri, 20 Nov 2020 08:59:59 +0000 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" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kg2Gt-0007Nn-6e; Fri, 20 Nov 2020 08:59:59 +0000 Received: by outflank-mailman (input) for mailman id 31780; Fri, 20 Nov 2020 08:59:58 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kg2Gs-0007Ng-48 for xen-devel@lists.xenproject.org; Fri, 20 Nov 2020 08:59:58 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 792855b5-19c4-49eb-ae08-9956c70f5db3; Fri, 20 Nov 2020 08:59:57 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A9A72AC0C; Fri, 20 Nov 2020 08:59:56 +0000 (UTC) Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kg2Gs-0007Ng-48 for xen-devel@lists.xenproject.org; Fri, 20 Nov 2020 08:59:58 +0000 X-Inumbo-ID: 792855b5-19c4-49eb-ae08-9956c70f5db3 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 792855b5-19c4-49eb-ae08-9956c70f5db3; Fri, 20 Nov 2020 08:59:57 +0000 (UTC) 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=1605862796; 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=vtzVT+psnRyLMZqf7NPV4DyyZ+QvtPWbucYiH+zRXaQ=; b=Wzg80ch2E0v/Wehh/deV82GMPaSrZptDAvMyyHCGg4qIMjmuQfg3MJLUMxFazOtBznhUYg wnBUm2qK30/jdUWPr33hwkDXVQ1Hl6KnZ6sa/wZ7MDO3mXqVcgTHmls5HRgHlL4IcTx07k E2SRyyReiYaZQkMr6LI4IZEkKNUxKlE= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A9A72AC0C; Fri, 20 Nov 2020 08:59:56 +0000 (UTC) Subject: Re: NetBSD dom0 PVH: hardware interrupts stalls To: Manuel Bouyer , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: xen-devel@lists.xenproject.org References: <20201118100025.ic7r3kfsbdnr6muz@Air-de-Roger> <20201118121403.GC3126@antioche.eu.org> <20201118143928.hvamuf7t7jycsrzb@Air-de-Roger> <20201119141915.igyb7djkw47rf2dt@Air-de-Roger> <20201119155718.GB4104@antioche.eu.org> <20201119165734.GA4903@antioche.eu.org> <20201119175733.GA6067@antioche.eu.org> <1a50e1e2-b69c-afd6-a179-316231512004@suse.com> <20201120082855.5z4cibcd5djlwmgp@Air-de-Roger> <20201120085249.GA1508@antioche.eu.org> From: Jan Beulich Message-ID: <97f371a9-00fe-33fe-8923-c247f44f9af6@suse.com> Date: Fri, 20 Nov 2020 09:59:57 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: <20201120085249.GA1508@antioche.eu.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 20.11.2020 09:52, Manuel Bouyer wrote: > On Fri, Nov 20, 2020 at 09:28:55AM +0100, Roger Pau Monné wrote: >>> i.e. at that point we're waiting for Dom0 to signal it's done handling >>> the IRQ. There is, however, a timer associated with this. Yet that's >>> actually to prevent the system getting stuck, i.e. the "in-flight" >>> state ought to clear 1ms later (when that timer expires), and hence >>> ought to be pretty unlikely to catch when non-zero _and_ something's >>> actually stuck. >> >> I somehow assumed the interrupt was in-flight because the printing to >> the Xen console caused one to be injected, and thus dom0 didn't had >> time to Ack it yet. > > What does Xen consider to be an ACK from the dom0 ? > AFAIK we have EOI only for LAPIC interrupts. Well, anything coming through the LAPIC needs ack-ing (except for the spurious interrupt of course), or else ISR won't get updated and further interrupts at this or lower priority can't be serviced (delivered) anymore. This includes interrupts originally coming through the IO-APIC. But the same constraint / requirement exists on baremetal. Jan