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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AF13C433F5 for ; Tue, 2 Nov 2021 09:26:24 +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 1E6EA60F4B for ; Tue, 2 Nov 2021 09:26:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1E6EA60F4B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:56280 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mhq3j-0006VK-1o for qemu-devel@archiver.kernel.org; Tue, 02 Nov 2021 05:26:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42810) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mhq1d-0005gV-9r for qemu-devel@nongnu.org; Tue, 02 Nov 2021 05:24:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:47918) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mhq1Z-0006dN-9V for qemu-devel@nongnu.org; Tue, 02 Nov 2021 05:24:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635845048; h=from:from:reply-to: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=wRbRYWb8MsAMnCKHFtOhh0rAaZgj3JFNywI4tYekwrM=; b=PxHIIWX39fAG+REJnLVhL++18By6jcADyWo+0tp28sjX8Gt9dRVYCoJQJusIIdaGqNVcbi Pti3SORxJzkdCgVT4Z9NEPfMzSGsWbmljtslS16HdshTlUwrY8tVkKuM6zJudWaxdS2csG /vf+jkufCOiTr3DBobInhWXVMDUicTA= 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-32-AsiTNBKzMweLEEGZI11CDg-1; Tue, 02 Nov 2021 05:23:59 -0400 X-MC-Unique: AsiTNBKzMweLEEGZI11CDg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6DB0281424F; Tue, 2 Nov 2021 09:23:57 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.194]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3ED671007625; Tue, 2 Nov 2021 09:23:56 +0000 (UTC) Date: Tue, 2 Nov 2021 09:23:52 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Michael S. Tsirkin" Subject: Re: [PULL 1/5] hw/pcie-root-port: Fix hotplug for PCI devices requiring IO Message-ID: References: <20210803205043.165034-1-mst@redhat.com> <20210803205043.165034-2-mst@redhat.com> <20210927053932-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: <20210927053932-mutt-send-email-mst@kernel.org> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.734, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Marcel Apfelbaum , Peter Maydell , qemu-devel@nongnu.org, Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Sep 27, 2021 at 05:49:15AM -0400, Michael S. Tsirkin wrote: > On Mon, Sep 27, 2021 at 10:33:42AM +0100, Daniel P. Berrangé wrote: > > On Tue, Aug 03, 2021 at 04:52:03PM -0400, Michael S. Tsirkin wrote: > > > From: Marcel Apfelbaum > > > > > > Q35 has now ACPI hotplug enabled by default for PCI(e) devices. > > > As opposed to native PCIe hotplug, guests like Fedora 34 > > > will not assign IO range to pcie-root-ports not supporting > > > native hotplug, resulting into a regression. > > > > > > Reproduce by: > > > qemu-bin -M q35 -device pcie-root-port,id=p1 -monitor stdio > > > device_add e1000,bus=p1 > > > In the Guest OS the respective pcie-root-port will have the IO range > > > disabled. > > > > > > Fix it by setting the "reserve-io" hint capability of the > > > pcie-root-ports so the firmware will allocate the IO range instead. > > > > > > Acked-by: Igor Mammedov > > > Signed-off-by: Marcel Apfelbaum > > > Message-Id: <20210802090057.1709775-1-marcel@redhat.com> > > > Reviewed-by: Michael S. Tsirkin > > > Signed-off-by: Michael S. Tsirkin > > > --- > > > hw/pci-bridge/gen_pcie_root_port.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > This change, when combined with the switch to ACPI based hotplug by > > default, is responsible for a significant regression in QEMU 6.1.0 > > > > It is no longer possible to have more than 15 pcie-root-port devices > > added to a q35 VM in 6.1.0. Before this I've had as many as 80+ devices > > present before I stopped trying to add more. > > > > https://gitlab.com/qemu-project/qemu/-/issues/641 > > > > This regression is significant, because it has broken the out of the > > box default configuration that OpenStack uses for booting all VMs. > > They add 16 pcie-root-ports by defalt to allow empty slots for device > > hotplug under q35 [1]. > > > Indeed, oops. Thanks for the report! We're at soft freeze now and this is still broken in git master. I don't recall seeing a fix for this problem on list and no one has commented on the bug report. Is anyone actively working on a fix for this release ? If not, I'm going to post a patch to revert to PCI native hotplug, because this was a significant regression in 6.1 that breaks openstack out of the box and we can't leave it broken again for 6.2. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|