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 1679AC433F5 for ; Tue, 5 Oct 2021 15:27:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDB7861159 for ; Tue, 5 Oct 2021 15:27:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235786AbhJEP3L (ORCPT ); Tue, 5 Oct 2021 11:29:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51114 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236198AbhJEP1i (ORCPT ); Tue, 5 Oct 2021 11:27:38 -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 Cc: "Michael S. Tsirkin" , linux-s390@vger.kernel.org, markver@us.ibm.com, Christian Borntraeger , qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Xie Yongji , stefanha@redhat.com, Raphael Norwitz , 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.