On 06/15/2009 04:20 PM, Anthony Liguori wrote:
then turns on the power. Command line options are the parts lying
around when we start.
btw, -drive needs to be separated:
-controller type=lsi1234,pci_addr=foobar,name=blah
-drive file=foo.img,controller=blah,index=0
-drive file=bar.img,controller=blah,index=1
Drives to not have pci addresses.
Drivers don't have indexes and buses but we specify it on the -drive
line.
Drives do have indexes. On old parallel scsi drives you set the
index by clicking a button on the back of the drive to cycle through
scsi addresses 0-7. An IDE drive's index is determined by the cable
(master/slave). A SATA drive's index is determined by which header
on the motherboard the drive connects to.
It's not at all that simple. SCSI has a hierarchical address
mechanism with 0-7 targets but then potentially multiple LUNs per
target. Today, we always emulate a single LUN per target but if we
ever wanted to support more than 7 disks on a SCSI controller, we
would have to add multiple LUN support too. So the current linear
unit= parameter is actually pretty broken for SCSI.
Well, another level in the hierarchy, but I don't think it materially
changes things.
For IDE, it's a combination of bus, slot, and master/slave. For
virtio, it's just a PCI address. What we really need is something
that is more opaque and controller specific.
virtio also has a bus (did you mean the pci bus for IDE?), master/slave
is the index. virtio doesn't have index, but IMO that was a mistake and
we should have designed it as a disk controller in the first place.
For instance, if we were going to do controllers...
-controller type=lsi1234,pci_addr=foobar,name=blah
-controller-disk controller=blah,target=0,lun=1,name=sda
-controller type=ide,pci_addr=barfoo,name=ide
-controller-disk controller=ide,slot=secondary,cable=slave,name=hdd
-drive file=foo.img,controller-disk=sda
-drive file=bar.img,controller-disk=hdd
And having "-hdd file=foo.img" be short-hand for "-drive
file=%s,controller-disk=%s".
Yeah.
If by bus you mean the if= parameter, then drives certainly do have
buses. Just try connecting the scsi drive from the previous
paragraph to a USB port.
No, I meant drive file=foo.img,bus=3. If that doesn't seem obvious
what it should do to you that's because it isn't at all obvious :-)
It ends up skipping a predefined number of locations in the drive
table. This is pretty broken fundamentally because it assumes
controllers always support a fixed number of devices. Nothing really
respects bus_id though so in practice, I assume it's almost
universally broken.
Isn't the drive table something totally internal? And how does bus=
relate to it?
Confused.
--
error compiling committee.c: too many arguments to function
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