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 3E243C433F5 for ; Tue, 5 Oct 2021 15:38:22 +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 D791C61131 for ; Tue, 5 Oct 2021 15:38:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D791C61131 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]:44078 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXmWK-0003gp-MP for qemu-devel@archiver.kernel.org; Tue, 05 Oct 2021 11:38:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37154) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXmKD-0001o7-Tl for qemu-devel@nongnu.org; Tue, 05 Oct 2021 11:25:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58126) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXmKC-00064A-J0 for qemu-devel@nongnu.org; Tue, 05 Oct 2021 11:25:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633447547; 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=kFyOXULNG37B2RXyMjh+ETk1npKEA5EyN+8as2bm268=; b=ZbNIhl0pRENQ97/cWykO6HHfxmdcvqdMNrf9ZmwOnbta49WtsYPbLBD7XCXGp5dt2/QIEN PGBCgkmTmVw5IT2bQmBbeObNkAIsyiYOZUApU1FG5fgvCERfzWYXyM105lCGCeQcseTaBx Xpiv1KrLFi2Jva2WHMpLqUyBJOyX1gY= 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-520-APCPKKKXMWSVumbKwVQo8w-1; Tue, 05 Oct 2021 11:25:44 -0400 X-MC-Unique: APCPKKKXMWSVumbKwVQo8w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E8E029F939; Tue, 5 Oct 2021 15:25:42 +0000 (UTC) Received: from localhost (unknown [10.39.192.167]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E82885F4F6; Tue, 5 Oct 2021 15:25:33 +0000 (UTC) From: Cornelia Huck To: Halil Pasic Subject: Re: [RFC PATCH 1/1] virtio: write back features before verify In-Reply-To: <20211005135909.2b8ab021.pasic@linux.ibm.com> Organization: Red Hat GmbH References: <20210930012049.3780865-1-pasic@linux.ibm.com> <87r1d64dl4.fsf@redhat.com> <20210930130350.0cdc7c65.pasic@linux.ibm.com> <87ilyi47wn.fsf@redhat.com> <20211001162213.18d7375e.pasic@linux.ibm.com> <87v92g3h9l.fsf@redhat.com> <20211002082128-mutt-send-email-mst@kernel.org> <20211004042323.730c6a5e.pasic@linux.ibm.com> <20211004040937-mutt-send-email-mst@kernel.org> <20211005124303.3abf848b.pasic@linux.ibm.com> <87lf372084.fsf@redhat.com> <20211005135909.2b8ab021.pasic@linux.ibm.com> User-Agent: Notmuch/0.32.1 (https://notmuchmail.org) Date: Tue, 05 Oct 2021 17:25:32 +0200 Message-ID: <87czoj1ok3.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, markver@us.ibm.com, "Michael S. Tsirkin" , Xie Yongji , qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, Halil Pasic , Christian Borntraeger , Raphael Norwitz , stefanha@redhat.com, virtualization@lists.linux-foundation.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Oct 05 2021, Halil Pasic wrote: > On Tue, 05 Oct 2021 13:13:31 +0200 > Cornelia Huck wrote: >> Or am I misunderstanding what you're getting at? >> > > Probably. I'm talking about pre- "do transport specific legacy detection > in the device instead of looking at VERSION_1" you are probably talking > about the post-state. If we had this new behavior for all relevant > hypervisors then we wouldn't need to do a thing in the guest. The current > code would work like charm. Yeah, I was thinking more about the desired state. We need to both fix QEMU (and other VMMs or devices should check whether they are doing the right thing) and add a workaround on the driver side to make it work with existing QEMUs.