qdev is a QEMU-internal API for device configuration and creation. It's the machinery that makes -device and device_add / device_del possible. Devices are being converted to qdev, and qdev evolves along with that. This page tracks how far we got, and what's still left to do.
- Drives done
- Host side: -drive if=none,id=<name>,<parameters>
- Guest side: -device virtio-blk-pci,drive=<name>
- Character devices done
- Host side: -chardev pty,id=<name>
- Guest side: -device isa-serial,chardev=<name>
- NICs done
- Host side: -netdev type=tap,id=<name>,fd=<tapfd>
- Guest side: -device virtio-net-pci,netdev=<name>
- Note that -netdev doesn't support VLANs
PC driver conversion status
- PIC, APIC, CPUs, memory not converted
- i440FX/PIIX3 done (host bridge, ISA bridge, USB, IDE) except for ACPI (PIIX3 function 3)
- ISA FDC, PS/2 keyboard & mouse, RTC, serial, parallel done
- VGA done (all variants, ISA & PCI), but doesn't work, because it needs to be initialized before i440fx_init_memory_mappings() runs.
- NICs done, but see "default optional devices" below
- Audio done, except for a few rarely used ISA devices
- Virtio done, except virtio-console still needs chardev hooked up (Amit's working on it as part of vmchannel)
- SCSI done
- USB HID (tablet, mouse, keyboard), storage, hub, host (pass-through), serial, braille done
- USB net patch posted
- USB bt (Bluetooth) not converted
- No way to ensure stable USB addresses
- IDE disks done, but see "default optional devices" below
- Watchdogs done
- Bluetooth not converted
- Option ROMs done
Default optional devices
QEMU creates a bunch of optional devices (NIC, CD-ROM, VGA, ...). They get automatically suppressed when you specify your own with -device & friends. Except NIC and CD-ROM (ide.1/master) don't. Work-around: suppress all optional devices with -nodefaults.
qdev options (and many others) can be read from a configuration file. -FOO VAR="VAL" becomes
[FOO] VAR = "VAL"
Option -readconfig FILE reads configuration from FILE, and -writeconfig FILE writes the current configuration to FILE. Needs more testing.
device_add / device_del are on par with -device: Any device you can create with -device you can hot-plug with device_add / device_del. As long as it's hot-pluggable, of course.
drive_add is on par with -drive. May still need drive_del.
Still need equivalents to -chardev and future -netdev (what drive_add is to -drive).
Nice to have, perhaps: info config like -writeconfig.
Gerd's git tree