From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46058) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c8m88-0001cZ-Nb for qemu-devel@nongnu.org; Mon, 21 Nov 2016 05:47:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c8m85-0005Sj-LV for qemu-devel@nongnu.org; Mon, 21 Nov 2016 05:47:20 -0500 References: <1479706302-2251-1-git-send-email-david@gibson.dropbear.id.au> <1479706302-2251-4-git-send-email-david@gibson.dropbear.id.au> From: Thomas Huth Message-ID: Date: Mon, 21 Nov 2016 11:47:13 +0100 MIME-Version: 1.0 In-Reply-To: <1479706302-2251-4-git-send-email-david@gibson.dropbear.id.au> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2 3/5] target-ppc: Allow eventual removal of old migration mistakes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson , mdroth@linux.vnet.ibm.com, dgilbert@redhat.com Cc: agraf@suse.de, aik@ozlabs.ru, lvivier@redhat.com, qemu-ppc@nongnu.org, qemu-devel@nongnu.org On 21.11.2016 06:31, David Gibson wrote: > Until very recently, the vmstate for ppc cpus included some poorly > thought out VMSTATE_EQUAL() components, that can easily break > migration compatibility, and did so between qemu-2.6 and later > versions. A hack was recently added which fixes this migration > breakage, but it leaves the unhelpful cruft of these fields in the > migration stream. > > dThis patch adds a new cpu property allowing these fields to be > removed from the stream entirely. This property is enabled by default > for the pseries-2.8 machine type - which comes after the fix - and for > all non-pseries machine types - which aren't mature enough to care > about cross-version migration. > > The migration hack remains in place for pseries-2.7 and earlier > machine types, allowing backwards and forwards migration with the > older machine types. > > This restricts the migration compatibility cruft to older machine > types, and at least opens the possibility of eventually deprecating > and removing it entirely. I like that idea! Patch looks fine, too, so: Reviewed-by: Thomas Huth