From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mx.groups.io with SMTP id smtpd.web12.20359.1621845772263064578 for ; Mon, 24 May 2021 01:42:52 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Zcn4L0Wn; spf=pass (domain: redhat.com, ip: 170.10.133.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621845771; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=RbpeAeLP07KkQ1osLAfpgEq3o4ymghn8byPRPV68kVs=; b=Zcn4L0WnWBWDyy//ompal1S3CD+EVhRCOM0rFqzEsu7CKeCUGnDi6D3uZw7gfuWKbySwBE rV2XynA9Po52RPvmA/uVni98gvQ4GDBhLPMf+O7I9vUowXLZaRqD86YpaEuzrA9L1IJ6Of aH6PUwDpj+QcUiTLF6AsPe1shOaFoyA= 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-298-Zs1NUFTbOJCIPDMlX27D8A-1; Mon, 24 May 2021 04:42:47 -0400 X-MC-Unique: Zs1NUFTbOJCIPDMlX27D8A-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3DD241005D59; Mon, 24 May 2021 08:42:46 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-112-185.ams2.redhat.com [10.36.112.185]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7BEA136DE; Mon, 24 May 2021 08:42:44 +0000 (UTC) To: Aaron Young , Anthony Perard , Ard Biesheuvel , Dann Frazier , Gary Lin , Jordan Justen , Julien Grall , edk2-devel-groups-io From: "Laszlo Ersek" Subject: deprecation notice: *dynamic* multi-VMM (QEMU vs. Xen) support in OvmfPkg Message-ID: Date: Mon, 24 May 2021 10:42:42 +0200 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Hi, the "OvmfXen.dsc" platform supports not only HVM guests, but also PVH guests. This platform does not run on QEMU. The historical "OvmfPkgIa32.dsc", "OvmfPkgIa32X64.dsc", "OvmfPkgX64.dsc" platforms support Xen guests, HVM only. They dynamically adapt to QEMU vs. Xen HVM. This dynamism has been a *huge* development and maintenance complication over the years. Another issue (which has been becoming ever more acute) is the NOOPT binary size, which certainly matters for debugging. With the introduction of OvmfXen in August 2019 , we formed a plan to remove the dynamism. Xen guests would only be targeted with the OvmfXen platform, while the "historical three" would only target QEMU. See . The incompatibility is that an existing Xen guest that uses one of the "OvmfPkgIa32.dsc", "OvmfPkgIa32X64.dsc", "OvmfPkgX64.dsc" firmware binaries will have to be reconfigured on the host to switch to the "OvmfXen.dsc" binary, after an edk2 package upgrade brings the above change to the host. Anthony originally proposed a 1 year grace period; we're now at 23 months. I've got 20 patches thus far, and those only take us about one third, or maybe one half, of the way. It's a very intrusive patch series, not one to revert after it's applied. My intent / hope is to get this merged into the (presumed) edk2-stable202108 tag. If you find that too early, please speak up. If you have another distro with LTS in mind whose package maintainer I should have put on the address list, please don't hesitate to add them. Please note that my question is not *if* we should do this, the question is *when* you can tolerate it, in your respective distros. Thanks, Laszlo