xref: /openbmc/qemu/docs/qdev-device-use.txt (revision 05caa062)
1= How to convert to -device & friends =
2
3=== Specifying Bus and Address on Bus ===
4
5In qdev, each device has a parent bus.  Some devices provide one or
6more buses for children.  You can specify a device's parent bus with
7-device parameter bus.
8
9A device typically has a device address on its parent bus.  For buses
10where this address can be configured, devices provide a bus-specific
11property.  Examples:
12
13    bus         property name       value format
14    PCI         addr                %x.%x    (dev.fn, .fn optional)
15    I2C         address             %u
16    SCSI        scsi-id             %u
17    IDE         unit                %u
18    HDA         cad                 %u
19    virtio-serial-bus  nr           %u
20    ccid-bus    slot                %u
21    USB         port                %d(.%d)*    (port.port...)
22
23Example: device i440FX-pcihost is on the root bus, and provides a PCI
24bus named pci.0.  To put a FOO device into its slot 4, use -device
25FOO,bus=/i440FX-pcihost/pci.0,addr=4.  The abbreviated form bus=pci.0
26also works as long as the bus name is unique.
27
28=== Block Devices ===
29
30A QEMU block device (drive) has a host and a guest part.
31
32In the general case, the guest device is connected to a controller
33device.  For instance, the IDE controller provides two IDE buses, each
34of which can have up to two devices, and each device is a guest part,
35and is connected to a host part.
36
37Except we sometimes lump controller, bus(es) and drive device(s) all
38together into a single device.  For instance, the ISA floppy
39controller is connected to up to two host drives.
40
41The old ways to define block devices define host and guest part
42together.  Sometimes, they can even define a controller device in
43addition to the block device.
44
45The new way keeps the parts separate: you create the host part with
46-drive, and guest device(s) with -device.
47
48The various old ways to define drives all boil down to the common form
49
50    -drive if=TYPE,bus=BUS,unit=UNIT,OPTS...
51
52TYPE, BUS and UNIT identify the controller device, which of its buses
53to use, and the drive's address on that bus.  Details depend on TYPE.
54
55Instead of bus=BUS,unit=UNIT, you can also say index=IDX.
56
57In the new way, this becomes something like
58
59   -drive if=none,id=DRIVE-ID,HOST-OPTS...
60   -device DEVNAME,drive=DRIVE-ID,DEV-OPTS...
61
62The old OPTS get split into HOST-OPTS and DEV-OPTS as follows:
63
64* file, format, snapshot, cache, aio, readonly, rerror, werror go into
65  HOST-OPTS.
66
67* cyls, head, secs and trans go into HOST-OPTS.  Future work: they
68  should go into DEV-OPTS instead.
69
70* serial goes into DEV-OPTS, for devices supporting serial numbers.
71  For other devices, it goes nowhere.
72
73* media is special.  In the old way, it selects disk vs. CD-ROM with
74  if=ide, if=scsi and if=xen.  The new way uses DEVNAME for that.
75  Additionally, readonly=on goes into HOST-OPTS.
76
77* addr is special, see if=virtio below.
78
79The -device argument differs in detail for each type of drive:
80
81* if=ide
82
83  -device DEVNAME,drive=DRIVE-ID,bus=IDE-BUS,unit=UNIT
84
85  where DEVNAME is either ide-hd or ide-cd, IDE-BUS identifies an IDE
86  bus, normally either ide.0 or ide.1, and UNIT is either 0 or 1.
87
88* if=scsi
89
90  The old way implicitly creates SCSI controllers as needed.  The new
91  way makes that explicit:
92
93  -device lsi53c895a,id=ID
94
95  As for all PCI devices, you can add bus=PCI-BUS,addr=DEVFN to
96  control the PCI device address.
97
98  This SCSI controller provides a single SCSI bus, named ID.0.  Put a
99  disk on it:
100
101  -device DEVNAME,drive=DRIVE-ID,bus=ID.0,scsi-id=UNIT
102
103  where DEVNAME is either scsi-hd, scsi-cd or scsi-generic.
104
105* if=floppy
106
107  -device floppy,unit=UNIT,drive=DRIVE-ID
108
109  Without any -device floppy,... you get an empty unit 0 and no unit
110  1.  You can use -nodefaults to suppress the default unit 0, see
111  "Default Devices".
112
113* if=virtio
114
115  -device virtio-blk-pci,drive=DRIVE-ID,class=C,vectors=V,ioeventfd=IOEVENTFD
116
117  This lets you control PCI device class and MSI-X vectors.
118
119  IOEVENTFD controls whether or not ioeventfd is used for virtqueue
120  notify.  It can be set to on (default) or off.
121
122  As for all PCI devices, you can add bus=PCI-BUS,addr=DEVFN to
123  control the PCI device address.  This replaces option addr available
124  with -drive if=virtio.
125
126* if=pflash, if=mtd, if=sd, if=xen are not yet available with -device
127
128For USB devices, the old way was actually different:
129
130    -usbdevice disk:format=FMT:FILENAME
131
132"Was" because "disk:" is gone since v2.12.0.
133
134The old way provided much less control than -drive's OPTS...  The new
135way fixes that:
136
137    -device usb-storage,drive=DRIVE-ID,removable=RMB
138
139The removable parameter gives control over the SCSI INQUIRY removable
140(RMB) bit.  USB thumbdrives usually set removable=on, while USB hard
141disks set removable=off.
142
143Bug: usb-storage pretends to be a block device, but it's really a SCSI
144controller that can serve only a single device, which it creates
145automatically.  The automatic creation guesses what kind of guest part
146to create from the host part, like -drive if=scsi.  Host and guest
147part are not cleanly separated.
148
149=== Character Devices ===
150
151A QEMU character device has a host and a guest part.
152
153The old ways to define character devices define host and guest part
154together.
155
156The new way keeps the parts separate: you create the host part with
157-chardev, and the guest device with -device.
158
159The various old ways to define a character device are all of the
160general form
161
162    -FOO FOO-OPTS...,LEGACY-CHARDEV
163
164where FOO-OPTS... is specific to -FOO, and the host part
165LEGACY-CHARDEV is the same everywhere.
166
167In the new way, this becomes
168
169    -chardev HOST-OPTS...,id=CHR-ID
170    -device DEVNAME,chardev=CHR-ID,DEV-OPTS...
171
172The appropriate DEVNAME depends on the machine type.  For type "pc":
173
174* -serial becomes -device isa-serial,iobase=IOADDR,irq=IRQ,index=IDX
175
176  This lets you control I/O ports and IRQs.
177
178* -parallel becomes -device isa-parallel,iobase=IOADDR,irq=IRQ,index=IDX
179
180  This lets you control I/O ports and IRQs.
181
182* -usbdevice braille doesn't support LEGACY-CHARDEV syntax.  It always
183  uses "braille".  With -device, this useful default is gone, so you
184  have to use something like
185
186  -device usb-braille,chardev=braille -chardev braille,id=braille
187
188* -usbdevice serial::chardev is gone since v2.12.0.  It became
189  -device usb-serial,chardev=dev.
190
191LEGACY-CHARDEV translates to -chardev HOST-OPTS... as follows:
192
193* null becomes -chardev null
194
195* pty, msmouse, wctablet, braille, stdio likewise
196
197* vc:WIDTHxHEIGHT becomes -chardev vc,width=WIDTH,height=HEIGHT
198
199* vc:<COLS>Cx<ROWS>C becomes -chardev vc,cols=<COLS>,rows=<ROWS>
200
201* con: becomes -chardev console
202
203* COM<NUM> becomes -chardev serial,path=COM<NUM>
204
205* file:FNAME becomes -chardev file,path=FNAME
206
207* pipe:FNAME becomes -chardev pipe,path=FNAME
208
209* tcp:HOST:PORT,OPTS... becomes -chardev socket,host=HOST,port=PORT,OPTS...
210
211* telnet:HOST:PORT,OPTS... becomes
212  -chardev socket,host=HOST,port=PORT,OPTS...,telnet=on
213
214* udp:HOST:PORT@LOCALADDR:LOCALPORT becomes
215  -chardev udp,host=HOST,port=PORT,localaddr=LOCALADDR,localport=LOCALPORT
216
217* unix:FNAME becomes -chardev socket,path=FNAME
218
219* /dev/parportN becomes -chardev parallel,file=/dev/parportN
220
221* /dev/ppiN likewise
222
223* Any other /dev/FNAME becomes -chardev serial,path=/dev/FNAME
224
225* mon:LEGACY-CHARDEV is special: it multiplexes the monitor onto the
226  character device defined by LEGACY-CHARDEV.  -chardev provides more
227  general multiplexing instead: you can connect up to four users to a
228  single host part.  You need to pass mux=on to -chardev to enable
229  switching the input focus.
230
231QEMU uses LEGACY-CHARDEV syntax not just to set up guest devices, but
232also in various other places such as -monitor or -net
233user,guestfwd=...  You can use chardev:CHR-ID in place of
234LEGACY-CHARDEV to refer to a host part defined with -chardev.
235
236=== Network Devices ===
237
238Host and guest part of network devices have always been separate.
239
240The old way to define the guest part looks like this:
241
242    -net nic,netdev=NET-ID,macaddr=MACADDR,model=MODEL,name=ID,addr=STR,vectors=V
243
244Except for USB it looked like this:
245
246    -usbdevice net:netdev=NET-ID,macaddr=MACADDR,name=ID
247
248"Looked" because "net:" is gone since v2.12.0.
249
250The new way is -device:
251
252    -device DEVNAME,netdev=NET-ID,mac=MACADDR,DEV-OPTS...
253
254DEVNAME equals MODEL, except for virtio you have to name the virtio
255device appropriate for the bus (virtio-net-pci for PCI), and for USB
256you have to use usb-net.
257
258The old name=ID parameter becomes the usual id=ID with -device.
259
260For PCI devices, you can add bus=PCI-BUS,addr=DEVFN to control the PCI
261device address, as usual.  The old -net nic provides parameter addr
262for that, which is silently ignored when the NIC is not a PCI device.
263
264For virtio-net-pci, you can control whether or not ioeventfd is used for
265virtqueue notify by setting ioeventfd= to on or off (default).
266
267-net nic accepts vectors=V for all models, but it's silently ignored
268except for virtio-net-pci (model=virtio).  With -device, only devices
269that support it accept it.
270
271Not all devices are available with -device at this time.  All PCI
272devices and ne2k_isa are.
273
274Some PCI devices aren't available with -net nic, e.g. i82558a.
275
276=== Graphics Devices ===
277
278Host and guest part of graphics devices have always been separate.
279
280The old way to define the guest graphics device is -vga VGA.  Not all
281machines support all -vga options.
282
283The new way is -device.  The mapping from -vga argument to -device
284depends on the machine type.  For machine "pc", it's:
285
286    std         -device VGA
287    cirrus      -device cirrus-vga
288    vmware      -device vmware-svga
289    qxl         -device qxl-vga
290    none        -nodefaults
291                disables more than just VGA, see "Default Devices"
292
293As for all PCI devices, you can add bus=PCI-BUS,addr=DEVFN to control
294the PCI device address.
295
296-device VGA supports properties bios-offset and bios-size, but they
297aren't used with machine type "pc".
298
299For machine "isapc", it's
300
301    std         -device isa-vga
302    cirrus      not yet available with -device
303    none        -nodefaults
304                disables more than just VGA, see "Default Devices"
305
306Bug: the new way doesn't work for machine types "pc" and "isapc",
307because it violates obscure device initialization ordering
308constraints.
309
310=== Audio Devices ===
311
312Host and guest part of audio devices have always been separate.
313
314The old way to define guest audio devices is -soundhw C1,...
315
316The new way is to define each guest audio device separately with
317-device.
318
319Map from -soundhw sound card name to -device:
320
321    ac97        -device AC97
322    cs4231a     -device cs4231a,iobase=IOADDR,irq=IRQ,dma=DMA
323    es1370      -device ES1370
324    gus         -device gus,iobase=IOADDR,irq=IRQ,dma=DMA,freq=F
325    hda         -device intel-hda,msi=MSI -device hda-duplex
326    sb16        -device sb16,iobase=IOADDR,irq=IRQ,dma=DMA,dma16=DMA16,version=V
327    adlib       not yet available with -device
328    pcspk       not yet available with -device
329
330For PCI devices, you can add bus=PCI-BUS,addr=DEVFN to control the PCI
331device address, as usual.
332
333=== USB Devices ===
334
335The old way to define a virtual USB device is -usbdevice DRIVER:OPTS...
336
337The new way is -device DEVNAME,DEV-OPTS...  Details depend on DRIVER:
338
339* ccid            -device usb-ccid
340* keyboard        -device usb-kbd
341* mouse           -device usb-mouse
342* tablet          -device usb-tablet
343* wacom-tablet    -device usb-wacom-tablet
344* u2f             -device u2f-{emulated,passthru}
345* braille         See "Character Devices"
346
347Until v2.12.0, we additionally had
348
349* host:...        See "Host Device Assignment"
350* disk:...        See "Block Devices"
351* serial:...      See "Character Devices"
352* net:...         See "Network Devices"
353
354=== Watchdog Devices ===
355
356Host and guest part of watchdog devices have always been separate.
357
358The old way to define a guest watchdog device is -watchdog DEVNAME.
359The new way is -device DEVNAME.  For PCI devices, you can add
360bus=PCI-BUS,addr=DEVFN to control the PCI device address, as usual.
361
362=== Host Device Assignment ===
363
364QEMU supports assigning host PCI devices (qemu-kvm only at this time)
365and host USB devices.  PCI devices can only be assigned with -device:
366
367    -device vfio-pci,host=ADDR,id=ID
368
369The old way to assign a USB host device
370
371    -usbdevice host:auto:BUS.ADDR:VID:PRID
372
373was removed in v2.12.0.  Any of BUS, ADDR, VID, PRID could be the
374wildcard *.
375
376The new way is
377
378    -device usb-host,hostbus=BUS,hostaddr=ADDR,vendorid=VID,productid=PRID
379
380Omitted options match anything.
381
382=== Default Devices ===
383
384QEMU creates a number of devices by default, depending on the machine
385type.
386
387-device DEVNAME... and global DEVNAME... suppress default devices for
388some DEVNAMEs:
389
390    default device      suppressing DEVNAMEs
391    CD-ROM              ide-cd, ide-hd, scsi-cd, scsi-hd
392    floppy              floppy, isa-fdc
393    parallel            isa-parallel
394    serial              isa-serial
395    VGA                 VGA, cirrus-vga, isa-vga, isa-cirrus-vga,
396                        vmware-svga, qxl-vga, virtio-vga, ati-vga,
397                        vhost-user-vga
398
399The default NIC is connected to a default part created along with it.
400It is *not* suppressed by configuring a NIC with -device (you may call
401that a bug).  -net and -netdev suppress the default NIC.
402
403-nodefaults suppresses all the default devices mentioned above, plus a
404few other things such as default SD-Card drive and default monitor.
405