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=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 60935C55179 for ; Tue, 27 Oct 2020 11:53:58 +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 BE32620829 for ; Tue, 27 Oct 2020 11:53:57 +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="Z3ueelly" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE32620829 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]:33514 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kXNY4-0000bM-NR for qemu-devel@archiver.kernel.org; Tue, 27 Oct 2020 07:53:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46944) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kXN81-00071c-Dq for qemu-devel@nongnu.org; Tue, 27 Oct 2020 07:27:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:56950) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kXN7z-0006gk-OS for qemu-devel@nongnu.org; Tue, 27 Oct 2020 07:27:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603798018; 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: in-reply-to:in-reply-to:references:references; bh=TkCAJl7bBMwMCvdHq7hbk1BLS6ZbMlCcd+iimsKeKzM=; b=Z3ueellyG9Y6Niq7wXDpNyc9nDLCmJj3KwYdrWcmp90IOulrHZpYIvlKwQZLFFirhMynk5 7AeRXXZEY1aTU0wlIGPLVZJXXDUfPJ8AAbM+gOVQwuy0EXhEKRcmY4hGZHqsf0p7QsdwDN xICh3k6SUY+zAWnA0PB0pneajLpwxko= 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-182-poalefKbOh-J4bhL0SPNtw-1; Tue, 27 Oct 2020 07:26:56 -0400 X-MC-Unique: poalefKbOh-J4bhL0SPNtw-1 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 D29B2809DC9; Tue, 27 Oct 2020 11:26:55 +0000 (UTC) Received: from redhat.com (ovpn-115-179.ams2.redhat.com [10.36.115.179]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 838865D9DD; Tue, 27 Oct 2020 11:26:47 +0000 (UTC) Date: Tue, 27 Oct 2020 07:26:44 -0400 From: "Michael S. Tsirkin" To: David Gibson Subject: Re: [PATCH] pci: Refuse to hotplug PCI Devices when the Guest OS is not ready Message-ID: <20201027072430-mutt-send-email-mst@kernel.org> References: <20201022080354-mutt-send-email-mst@kernel.org> <20201022235632.7f69ddc9@yekko.fritz.box> <20201022100028-mutt-send-email-mst@kernel.org> <20201022102857-mutt-send-email-mst@kernel.org> <20201022110016-mutt-send-email-mst@kernel.org> <20201026174537.128a4173@yekko.fritz.box> MIME-Version: 1.0 In-Reply-To: <20201026174537.128a4173@yekko.fritz.box> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/27 01:06:07 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H5=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: Julia Suvorova , qemu devel list Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Oct 26, 2020 at 05:45:37PM +1100, David Gibson wrote: > On Fri, 23 Oct 2020 09:26:48 +0300 > Marcel Apfelbaum wrote: > > > Hi Michael, > > > > On Thu, Oct 22, 2020 at 6:01 PM Michael S. Tsirkin wrote: > > > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > [...] > > Simplistic does not mean wrong or incorrect. > > I fail to see why it is not enough. > > > > What QEMU can do better? Wait an unbounded time for the blinking to finish? > > It certainly shouldn't wait an unbounded time. But a wait with timeout > seems worth investigating to me. If it's helpful, I'd add a query to check state so management can figure out why doesn't guest see device yet. But otherwise just buffer the request until such time as we can deliver it to guest ... > > What if we have a buggy guest with a kernel stuck in blinking? > > Is QEMU's responsibility to emulate the operator itself? Because the > > operator > > is the one who is supposed to wait. > > > > > > Thanks, > > Marcel > > > > [...] > > > -- > David Gibson > Principal Software Engineer, Virtualization, Red Hat