Am 11.10.2010 12:18, schrieb Gleb Natapov: > Currently if VM is started with multiple disks it is almost impossible to > guess which one of them will be used as boot device especially if there > is a mix of ATA/virtio/SCSI devices. Essentially BIOS decides the order > and without looking into the code you can't tell what the order will > be (and in qemu-kvm if boot=on is used it brings even more havoc). We > should allow fine-grained control of boot order from qemu command line, > or as a minimum control what device will be used for booting. > > To do that along with inventing syntax to specify boot order on qemu > command line we need to communicate boot order to seabios via fw_cfg > interface. For that we need to have a way to unambiguously specify a > disk from qemu to seabios. PCI bus address is not enough since not all > devices are PCI (do we care about them?)
Floppy? Yes, I think we do. > and since one PCI device may > control more then one disk (ATA slave/master, SCSI LUNs). We can do what > EDD specification does. Describe disk as: > bus type (isa/pci), > address on a bus (16 bit base address for isa, b/s/f for pci) > device type (ATA/SCSI/VIRTIO) > device path (slave/master for ATA, LUN for SCSI, nothing for virtio) If we had a qdev ID for all devices (which I think we should have anyway), would this work or is a string not really handy enough? Kevin
