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=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 95948C33CB1 for ; Fri, 17 Jan 2020 11:34:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 61FC92073A for ; Fri, 17 Jan 2020 11:34:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GtRbf/+R" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61FC92073A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55824 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1isPtX-0007kX-JB for qemu-devel@archiver.kernel.org; Fri, 17 Jan 2020 06:34:31 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35682) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1isPsh-00078d-HI for qemu-devel@nongnu.org; Fri, 17 Jan 2020 06:33:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1isPsd-0007dT-JW for qemu-devel@nongnu.org; Fri, 17 Jan 2020 06:33:39 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:52152 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1isPsd-0007cx-FZ for qemu-devel@nongnu.org; Fri, 17 Jan 2020 06:33:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579260814; h=from:from:reply-to:subject:subject: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=QuwRKDLp5krrw9QIF7Gb/dDM0E7LLZLPSd/2TUTrTfc=; b=GtRbf/+R5L6wkwMPYPlSn7RYyzICDsNBIvlNTNQkfWYFaxgT2iY5Nz5K/KZmOw4G7aCNqP DNVnkExyXADhMS2782eBbn6Pra35kk6eTFy+2uN3JaSIRY/tVJkBJ8Ooo5Ms43ExNIP3fD htTNVvpZVjny9LCVF6sdrTCg5YAsY2k= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-313-D1QB-X9-MQKFXpsZWy6AtQ-1; Fri, 17 Jan 2020 06:33:33 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 31B4D8017CC; Fri, 17 Jan 2020 11:33:32 +0000 (UTC) Received: from gondolin (dhcp-192-245.str.redhat.com [10.33.192.245]) by smtp.corp.redhat.com (Postfix) with ESMTP id 251F95D9CD; Fri, 17 Jan 2020 11:33:31 +0000 (UTC) Date: Fri, 17 Jan 2020 12:33:28 +0100 From: Cornelia Huck To: Christian Borntraeger Subject: Re: [PATCH v2] s390x: adapter routes error handling Message-ID: <20200117123328.02498aee.cohuck@redhat.com> In-Reply-To: <528e1add-6a53-7c55-83a2-f10491be4e4d@de.ibm.com> References: <20200117111147.5006-1-cohuck@redhat.com> <528e1add-6a53-7c55-83a2-f10491be4e4d@de.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: D1QB-X9-MQKFXpsZWy6AtQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Halil Pasic , Paolo Bonzini , qemu-s390x@nongnu.org, qemu-devel@nongnu.org, Thomas Huth Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 17 Jan 2020 12:22:45 +0100 Christian Borntraeger wrote: > On 17.01.20 12:11, Cornelia Huck wrote: > > If the kernel irqchip has been disabled, we don't want the > > {add,release}_adapter_routes routines to call any kvm_irqchip_* > > interfaces, as they may rely on an irqchip actually having been > > created. Just take a quick exit in that case instead. > > > > Also initialize routes->gsi[] with -1 in the virtio-ccw handling, > > to make sure we don't trip over other errors, either. (Nobody > > else uses the gsi array in that structure.) > > > > Fixes: d426d9fba8ea ("s390x/virtio-ccw: wire up irq routing and irqfds") > > Signed-off-by: Cornelia Huck > > I think it was actually quite good to see an error, because something went wrong > (kvmirqchip being off). Now the error (crash) was certainly a bad one. > What happens after this patch? > To me it _looks_ like every caller of set_guest_notifiers would get the ENOSYS > and bail out with an error so this should be ok, but it would be good > to add something to the patch description that says so. > > Something like "instead of crashing we now fail with an error message for vhost > and friends" > of course only if this is true. It should work in the same way as it does for tcg right now (we return -ENOSYS in the non-kvm flic as well). If you're not using irqfd, everything will work just fine. What about the following: "If you are trying to use irqfd without a kernel irqchip, we will fail with an error." ? There probably won't be many people seeing anything like this, as I guess most people will delegate the irqfd setup to libvirt anyway, which will not turn off the kernel irqchip.