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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 7BBE9C433EF for ; Wed, 9 Feb 2022 13:22:15 +0000 (UTC) Received: from localhost ([::1]:34912 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nHmvG-0001bV-CK for qemu-devel@archiver.kernel.org; Wed, 09 Feb 2022 08:22:14 -0500 Received: from eggs.gnu.org ([209.51.188.92]:46840) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHmOj-00021k-F9 for qemu-devel@nongnu.org; Wed, 09 Feb 2022 07:48:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:28064) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nHmOf-0001YK-Q6 for qemu-devel@nongnu.org; Wed, 09 Feb 2022 07:48:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644410905; 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=dLp4Cg1jv2YFe7xWjj0q79odDaNdA/q3J9Zn7C7YD1M=; b=ROkiDLFLXUN6Efyn06df+dBh7NTEwfAAEhXfNHKB72DJr6qghTc/o/nQkNytS8P3lLno0Y eIIrpIs8l0dKx75MYpvKYjN1cPEtSpUIcUn2+CbKyKXVj8ehHIjDgWzQhs03aHTFysUVrT 2s+XFL/6roQLoilTGAhhwGWbx3JpE9c= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-562-FF8RcTrUNYirMEEkSfmkYA-1; Wed, 09 Feb 2022 07:48:22 -0500 X-MC-Unique: FF8RcTrUNYirMEEkSfmkYA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7A6BF39382; Wed, 9 Feb 2022 12:48:21 +0000 (UTC) Received: from localhost (unknown [10.39.194.43]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1CED77C0C9; Wed, 9 Feb 2022 12:48:20 +0000 (UTC) From: Cornelia Huck To: eric.auger@redhat.com, "Michael S. Tsirkin" Subject: Re: [PATCH v2 2/4] virtio-iommu: Default to bypass during boot In-Reply-To: <6dbd9ef6-99da-850a-114d-53486c91a05f@redhat.com> Organization: Red Hat GmbH References: <20220127142940.671333-1-jean-philippe@linaro.org> <20220127142940.671333-3-jean-philippe@linaro.org> <87wni5tftq.fsf@redhat.com> <20220208160642-mutt-send-email-mst@kernel.org> <87r18cthwd.fsf@redhat.com> <6dbd9ef6-99da-850a-114d-53486c91a05f@redhat.com> User-Agent: Notmuch/0.34 (https://notmuchmail.org) Date: Wed, 09 Feb 2022 13:48:19 +0100 Message-ID: <87o83gtdd8.fsf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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 Received-SPF: pass client-ip=170.10.133.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Cc: lvivier@redhat.com, Jean-Philippe Brucker , thuth@redhat.com, qemu-devel@nongnu.org, pasic@linux.ibm.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Feb 09 2022, Eric Auger wrote: > Hi, > > On 2/9/22 12:10 PM, Cornelia Huck wrote: >> On Tue, Feb 08 2022, "Michael S. Tsirkin" wrote: >> >>> On Tue, Feb 08, 2022 at 06:42:57PM +0100, Cornelia Huck wrote: >>>> On Thu, Jan 27 2022, Jean-Philippe Brucker wrote: >>>> >>>>> @@ -988,9 +1025,9 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) >>>>> virtio_add_feature(&s->features, VIRTIO_IOMMU_F_INPUT_RANGE); >>>>> virtio_add_feature(&s->features, VIRTIO_IOMMU_F_DOMAIN_RANGE); >>>>> virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP); >>>>> - virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS); >>>>> virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MMIO); >>>>> virtio_add_feature(&s->features, VIRTIO_IOMMU_F_PROBE); >>>>> + virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS_CONFIG); >>>> Hm. In the other patch, you say that you don't support cross-version >>>> migration (I assume across QEMU versions?) >>> I missed that ... where does it say this? >> In bf447d9b-c039-ccdc-f24f-ab8b56c1b196@redhat.com and follow-ups >> (unless I misread that; maybe it's more about this concrete boundary and >> not generally?) > > We were considering the virtio-iommu QEMU device currently isn't used > for production yet, as far as we know, because we were missing the ACPI > integration. > So we envisionned to not care about mig subsections and just add the new > field in the VMState. > > would that make sense? If people are currently mostly playing with this device, it would not hurt too much, I guess. (Should we document expectations somewhere?) Adding a compat prop for this feature would be easy enough, but juggling subsections is a bit more involved, so I see the argument for not caring about them. > > Thanks > > Eric > >> >>>> Because changing the feature >>>> set will be guest-visible, and would need some compat handling if you >>>> plan to support this.