From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38803) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UfX3Y-0007uB-Ei for qemu-devel@nongnu.org; Thu, 23 May 2013 11:03:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UfX3T-0000Qb-01 for qemu-devel@nongnu.org; Thu, 23 May 2013 11:03:52 -0400 Received: from mail-gg0-x232.google.com ([2607:f8b0:4002:c02::232]:55083) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UfWrY-00055B-H8 for qemu-devel@nongnu.org; Thu, 23 May 2013 10:51:28 -0400 Received: by mail-gg0-f178.google.com with SMTP id a5so1183747ggn.9 for ; Thu, 23 May 2013 07:51:28 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <519E2CE5.2050501@redhat.com> Date: Thu, 23 May 2013 16:51:17 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1368059472-25071-1-git-send-email-david@gibson.dropbear.id.au> <1368059472-25071-6-git-send-email-david@gibson.dropbear.id.au> <20130523110407.GB17480@redhat.com> In-Reply-To: <20130523110407.GB17480@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, David Gibson Il 23/05/2013 13:04, Michael S. Tsirkin ha scritto: >> > Most current uses of pci_find_domain() are for error or informational >> > messages, so the change in identifiers should be harmless. The exception >> > is pci_get_dev_path(), whose results form part of migration streams. To >> > maintain compatibility with old migration streams, the PIIX PCI host is >> > altered to always supply "0000" for this path, which matches the old domain >> > number (since the code didn't actually support domains other than 0). >> > >> > For the pseries (spapr) PCI bridge we use a different platform-unique >> > identifier (pseries machines can routinely have dozens of PCI host >> > bridges). Theoretically that breaks migration streams, but given that we >> > don't yet have migration support for pseries, it doesn't matter. >> > >> > Any other machines that have working migration support including PCI >> > devices will need to be updated to maintain migration stream compatibility. >> > >> > Signed-off-by: David Gibson > AFAIK PC is the only one with working migration, yes, but > we have Q35 as well which can be migrated. Are we already supporting backwards/forwards migration with Q35? Paolo