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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3B4CAC4361B for ; Thu, 17 Dec 2020 13:14:32 +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 675CC2389A for ; Thu, 17 Dec 2020 13:14:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 675CC2389A 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]:55370 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kpt70-00023Z-FS for qemu-devel@archiver.kernel.org; Thu, 17 Dec 2020 08:14:30 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37566) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kpt1K-0005TT-Du for qemu-devel@nongnu.org; Thu, 17 Dec 2020 08:08:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39595) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kpt1I-0003nP-Ah for qemu-devel@nongnu.org; Thu, 17 Dec 2020 08:08:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608210515; 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=3nvDZ9epNqdeZQGDMg45qqCWSp6yh19yOo80UKE+c7E=; b=d/2oe04yYQ60PD7bD7kUjr7WdfTs0XHz7tC8ghc+Z4K8Jo1UiR3xE5fqlw0uYSENyAWwCX dre2hkRbkHacGWR8aziSvrYoLL/sNxK5tWrno1jNkFyEMd4V9Irlz3a0ig1sSAZZ7Us6A3 d8aoawph/lMju9fkJXULKSiA0cjLduA= 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-276-W5wuA-RuPAOtS3NWEMt-PA-1; Thu, 17 Dec 2020 08:08:33 -0500 X-MC-Unique: W5wuA-RuPAOtS3NWEMt-PA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5EAD1800D55; Thu, 17 Dec 2020 13:08:32 +0000 (UTC) Received: from gondolin (ovpn-113-176.ams2.redhat.com [10.36.113.176]) by smtp.corp.redhat.com (Postfix) with ESMTP id B90E41A353; Thu, 17 Dec 2020 13:08:19 +0000 (UTC) Date: Thu, 17 Dec 2020 14:08:17 +0100 From: Cornelia Huck To: Matthew Rosato Subject: Re: [RFC 2/8] s390x/pci: MSI-X isn't strictly required for passthrough Message-ID: <20201217140817.30bae4e4.cohuck@redhat.com> In-Reply-To: <9fc712d1-2350-f16f-7073-87162def13eb@linux.ibm.com> References: <1607546066-2240-1-git-send-email-mjrosato@linux.ibm.com> <1607546066-2240-3-git-send-email-mjrosato@linux.ibm.com> <20201210112806.61b0c854.cohuck@redhat.com> <9fc712d1-2350-f16f-7073-87162def13eb@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: thuth@redhat.com, pmorel@linux.ibm.com, david@redhat.com, schnelle@linux.ibm.com, richard.henderson@linaro.org, qemu-s390x@nongnu.org, qemu-devel@nongnu.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, alex.williamson@redhat.com, mst@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 10 Dec 2020 10:13:29 -0500 Matthew Rosato wrote: > On 12/10/20 5:28 AM, Cornelia Huck wrote: > > On Wed, 9 Dec 2020 15:34:20 -0500 > > Matthew Rosato wrote: > > > >> s390 PCI currently disallows PCI devices without the MSI-X capability. > >> However, this fence doesn't make sense for passthrough devices. Move > >> the check to only fence emulated devices (e.g., virtio). > >> > >> Signed-off-by: Matthew Rosato > >> Reviewed-by: Pierre Morel > >> --- > >> hw/s390x/s390-pci-bus.c | 14 ++++++++------ > >> 1 file changed, 8 insertions(+), 6 deletions(-) > >> > >> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > >> index 05f7460..afad048 100644 > >> --- a/hw/s390x/s390-pci-bus.c > >> +++ b/hw/s390x/s390-pci-bus.c > >> @@ -1028,12 +1028,12 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > >> s390_pci_get_clp_info(pbdev); > >> } else { > >> pbdev->fh |= FH_SHM_EMUL; > >> - } > >> > >> - if (s390_pci_msix_init(pbdev)) { > >> - error_setg(errp, "MSI-X support is mandatory " > >> - "in the S390 architecture"); > >> - return; > >> + if (s390_pci_msix_init(pbdev)) { > >> + error_setg(errp, "MSI-X support is mandatory " > >> + "in the S390 architecture"); > >> + return; > >> + } > >> } > >> > >> if (dev->hotplugged) { > >> @@ -1073,7 +1073,9 @@ static void s390_pcihost_unplug(HotplugHandler *hotplug_dev, DeviceState *dev, > >> devfn = pci_dev->devfn; > >> qdev_unrealize(dev); > >> > >> - s390_pci_msix_free(pbdev); > >> + if (pbdev->fh & FH_SHM_EMUL) { > >> + s390_pci_msix_free(pbdev); > >> + } > >> s390_pci_iommu_free(s, bus, devfn); > >> pbdev->pdev = NULL; > >> pbdev->state = ZPCI_FS_RESERVED; > > > > Remind me: Wasn't it only msi that was strictly required (i.e., not msi-x?) > > > > Can we generally relax this requirement, possibly with some changes in > > the adapter interrupt mapping? I might misremember, though. > > > > Yes, but even so our current emulation support only sets up for MSI-X, > it does not have an msi_init() equivalent. I do believe that this > requirement can be relaxed at some point for the emulation support as > well, but the focus on this set was to at least stop fencing passthrough > for no reason. Looking back to when this was introduced, I see that 857cc71985dc ("s390x/pci: merge msix init functions") actually makes this mandatory and states that nothing changes for passthrough. Has anything changed regarding msi-x in the architecture in the meantime?