On 22 June 2015 at 10:59, Markus Armbruster <arm...@redhat.com> wrote: > What about this instead: > > 1. When -device creation connects a qdev_prop_drive property to a > backend, fail when the backend has a DriveInfo and the DriveInfo has > type != IF_NONE. Note: the connection is made in parse_drive().
So, the reason I didn't do this is that it breaks some options that currently work (the ones where the board doesn't pick up the device and so there's no conflict). I preferred to make those "continue to function, but warn", but if we're happy to make this a hard error we could go this way. > 2. This breaks -drive if=virtio and possibly more. That's because for > if=virtio, we create input for -device creation that asks to connect > this IF_VIRTIO drive. To unbreak it, mark the DriveInfo when we create > such input, and make parse_drive() accept backends so marked. To find > the places that need to mark, examine users of option group "device". A > quick, sloppy grep shows a bit over a dozen candidates. Not too bad. How do we then tell the difference between parse_drive() being called for the auto-created virtio device, and it then later being called as part of connecting the drive to a manually created device? My grep (which was for 'qemu_find_opts.*device' -- is that right?) suggests that in fact the only case we need to care about is the one where we auto-create the virtio device (the other grep matches are not relevant). > In my opinion, a board that specifies a default interface type it > doesn't support is simply broken, and should be fixed. I'm inclined to agree, but I bet we have a lot. It doesn't help that the default if the machine doesn't specify anything is "IDE", not "you can't use a default interface"... > Even if we fix that, we could still reach this case when the board > claims only *some* of the drives for its default type. Example: > > $ qemu-system-x86_64 -nodefaults -S -display none -drive > if=floppy,file=tmp.qcow2,index=99 > Warning: Orphaned drive without device: > id=floppy99,file=tmp.qcow2,if=floppy,bus=0,unit=99 > > Compare: > > $ qemu-system-x86_64 -nodefaults -S -display none -drive > if=ide,file=tmp.qcow2,index=99 > qemu-system-x86_64: Too many IDE buses defined (50 > 2) > > Crap shot. > > If we have boards that don't claim *any* interface type, we need to give > them a .block_default_type that rejects -drive without an explicit if=. We have several of these boards, yes. (for example, hw/arm/cubieboard.c) thanks -- PMM
