On Mon, 2010-06-14 at 08:39 +0200, Markus Armbruster wrote: > Alex Williamson <alex.williamson@xxxxxxxxxx> writes: > > > qdev_get_dev_path() is intended to be the canonical utility for creating > > a string representing the qdev hierarchy of a device. The path consists > > of bus and device names as well as identified properties of the immediate > > parent bus and device. This results in strings like: > > > > "/main-system-bus/pci.0,addr=00.0/i440FX" > > "/main-system-bus/pci.0,addr=01.0/PIIX3" > > "/main-system-bus/pci.0,addr=02.0/cirrus-vga" > > "/main-system-bus/pci.0/isa.0/mc146818rtc" > > "/main-system-bus/pci.0/isa.0/isa-serial" > > "/main-system-bus/pci.0/isa.0/i8042" > > "/main-system-bus/pci.0/isa.0/isa-fdc" > > "/main-system-bus/pci.0,addr=03.0/i82551,mac=52:54:00:12:34:56" > > "/main-system-bus/pci.0,addr=04.0/virtio-net-pci,mac=52:54:00:12:34:57" > > "/main-system-bus/pci.0,addr=05.0/e1000,mac=52:54:00:12:34:58" > > "/main-system-bus/pci.0,addr=06.0/rtl8139,mac=52:54:00:12:34:59" > > "/main-system-bus/pci.0,addr=07.0/pcnet,mac=52:54:00:12:34:5a" > > "/main-system-bus/pci.0,addr=01.1/piix3-ide" > > "/main-system-bus/pci.0,addr=01.3/PIIX4_PM" > > "/main-system-bus/pci.0,addr=08.0/lsi53c895a" > > "/main-system-bus/pci.0,addr=09.0/virtio-blk-pci" > > > > There are two primary targets for these strings. The first is vmsave, where > > we currently use a device provided string plus instance number to track > > SaveStateEntries. This fails when we introduce device hotplug, particularly > > in a case were we have gaps in the instance numbers that cannot easily be > > reproduced on a migration target. The second is for naming RAMBlocks. For > > these, we would like a string that matches the vmstate string. > > Could you explain why you add "identified properties of the immediate > parent bus and device"? They make the result ver much *not* a "dev > path" in the qdev sense... In order to try to get a unique string. Without looking into device properties, two e1000s would both be: /main-system-bus/pci.0/e1000 /main-system-bus/pci.0/e1000 Which is no better than simply "e1000" and would require us to fall back to instance ids again. The goal here is that anything that makes use of passing a dev when registering a vmstate gets an instance id of zero. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
