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qemu/hmp-commands.hx
Ilya Maximets cb039ef3d9 net: add initial support for AF_XDP network backend 
AF_XDP is a network socket family that allows communication directly
with the network device driver in the kernel, bypassing most or all
of the kernel networking stack.  In the essence, the technology is
pretty similar to netmap.  But, unlike netmap, AF_XDP is Linux-native
and works with any network interfaces without driver modifications.
Unlike vhost-based backends (kernel, user, vdpa), AF_XDP doesn't
require access to character devices or unix sockets.  Only access to
the network interface itself is necessary.

This patch implements a network backend that communicates with the
kernel by creating an AF_XDP socket.  A chunk of userspace memory
is shared between QEMU and the host kernel.  4 ring buffers (Tx, Rx,
Fill and Completion) are placed in that memory along with a pool of
memory buffers for the packet data.  Data transmission is done by
allocating one of the buffers, copying packet data into it and
placing the pointer into Tx ring.  After transmission, device will
return the buffer via Completion ring.  On Rx, device will take
a buffer form a pre-populated Fill ring, write the packet data into
it and place the buffer into Rx ring.

AF_XDP network backend takes on the communication with the host
kernel and the network interface and forwards packets to/from the
peer device in QEMU.

Usage example:

  -device virtio-net-pci,netdev=guest1,mac=00:16:35:AF:AA:5C
  -netdev af-xdp,ifname=ens6f1np1,id=guest1,mode=native,queues=1

XDP program bridges the socket with a network interface.  It can be
attached to the interface in 2 different modes:

1. skb - this mode should work for any interface and doesn't require
         driver support.  With a caveat of lower performance.

2. native - this does require support from the driver and allows to
            bypass skb allocation in the kernel and potentially use
            zero-copy while getting packets in/out userspace.

By default, QEMU will try to use native mode and fall back to skb.
Mode can be forced via 'mode' option.  To force 'copy' even in native
mode, use 'force-copy=on' option.  This might be useful if there is
some issue with the driver.

Option 'queues=N' allows to specify how many device queues should
be open.  Note that all the queues that are not open are still
functional and can receive traffic, but it will not be delivered to
QEMU.  So, the number of device queues should generally match the
QEMU configuration, unless the device is shared with something
else and the traffic re-direction to appropriate queues is correctly
configured on a device level (e.g. with ethtool -N).
'start-queue=M' option can be used to specify from which queue id
QEMU should start configuring 'N' queues.  It might also be necessary
to use this option with certain NICs, e.g. MLX5 NICs.  See the docs
for examples.

In a general case QEMU will need CAP_NET_ADMIN and CAP_SYS_ADMIN
or CAP_BPF capabilities in order to load default XSK/XDP programs to
the network interface and configure BPF maps.  It is possible, however,
to run with no capabilities.  For that to work, an external process
with enough capabilities will need to pre-load default XSK program,
create AF_XDP sockets and pass their file descriptors to QEMU process
on startup via 'sock-fds' option.  Network backend will need to be
configured with 'inhibit=on' to avoid loading of the program.
QEMU will need 32 MB of locked memory (RLIMIT_MEMLOCK) per queue
or CAP_IPC_LOCK.

There are few performance challenges with the current network backends.

First is that they do not support IO threads.  This means that data
path is handled by the main thread in QEMU and may slow down other
work or may be slowed down by some other work.  This also means that
taking advantage of multi-queue is generally not possible today.

Another thing is that data path is going through the device emulation
code, which is not really optimized for performance.  The fastest
"frontend" device is virtio-net.  But it's not optimized for heavy
traffic either, because it expects such use-cases to be handled via
some implementation of vhost (user, kernel, vdpa).  In practice, we
have virtio notifications and rcu lock/unlock on a per-packet basis
and not very efficient accesses to the guest memory.  Communication
channels between backend and frontend devices do not allow passing
more than one packet at a time as well.

Some of these challenges can be avoided in the future by adding better
batching into device emulation or by implementing vhost-af-xdp variant.

There are also a few kernel limitations.  AF_XDP sockets do not
support any kinds of checksum or segmentation offloading.  Buffers
are limited to a page size (4K), i.e. MTU is limited.  Multi-buffer
support implementation for AF_XDP is in progress, but not ready yet.
Also, transmission in all non-zero-copy modes is synchronous, i.e.
done in a syscall.  That doesn't allow high packet rates on virtual
interfaces.

However, keeping in mind all of these challenges, current implementation
of the AF_XDP backend shows a decent performance while running on top
of a physical NIC with zero-copy support.

Test setup:

2 VMs running on 2 physical hosts connected via ConnectX6-Dx card.
Network backend is configured to open the NIC directly in native mode.
The driver supports zero-copy.  NIC is configured to use 1 queue.

Inside a VM - iperf3 for basic TCP performance testing and dpdk-testpmd
for PPS testing.

iperf3 result:
 TCP stream      : 19.1 Gbps

dpdk-testpmd (single queue, single CPU core, 64 B packets) results:
 Tx only         : 3.4 Mpps
 Rx only         : 2.0 Mpps
 L2 FWD Loopback : 1.5 Mpps

In skb mode the same setup shows much lower performance, similar to
the setup where pair of physical NICs is replaced with veth pair:

iperf3 result:
  TCP stream      : 9 Gbps

dpdk-testpmd (single queue, single CPU core, 64 B packets) results:
  Tx only         : 1.2 Mpps
  Rx only         : 1.0 Mpps
  L2 FWD Loopback : 0.7 Mpps

Results in skb mode or over the veth are close to results of a tap
backend with vhost=on and disabled segmentation offloading bridged
with a NIC.

Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> (docker/lcitool)
Signed-off-by: Jason Wang <jasowang@redhat.com>
2023-09-18 14:36:13 +08:00

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HXCOMM Use DEFHEADING() to define headings in both help text and rST.
HXCOMM Text between SRST and ERST is copied to the rST version and
HXCOMM discarded from C version.
HXCOMM DEF(command, args, callback, arg_string, help) is used to construct
HXCOMM monitor commands
HXCOMM HXCOMM can be used for comments, discarded from both rST and C.
{
.name = "help|?",
.args_type = "name:S?",
.params = "[cmd]",
.help = "show the help",
.cmd = hmp_help,
.flags = "p",
},
SRST
``help`` or ``?`` [*cmd*]
Show the help for all commands or just for command *cmd*.
ERST
{
.name = "commit",
.args_type = "device:B",
.params = "device|all",
.help = "commit changes to the disk images (if -snapshot is used) or backing files",
.cmd = hmp_commit,
},
SRST
``commit``
Commit changes to the disk images (if -snapshot is used) or backing files.
If the backing file is smaller than the snapshot, then the backing file
will be resized to be the same size as the snapshot. If the snapshot is
smaller than the backing file, the backing file will not be truncated.
If you want the backing file to match the size of the smaller snapshot,
you can safely truncate it yourself once the commit operation successfully
completes.
ERST
{
.name = "quit|q",
.args_type = "",
.params = "",
.help = "quit the emulator",
.cmd = hmp_quit,
.flags = "p",
},
SRST
``quit`` or ``q``
Quit the emulator.
ERST
{
.name = "exit_preconfig",
.args_type = "",
.params = "",
.help = "exit the preconfig state",
.cmd = hmp_exit_preconfig,
.flags = "p",
},
SRST
``exit_preconfig``
This command makes QEMU exit the preconfig state and proceed with
VM initialization using configuration data provided on the command line
and via the QMP monitor during the preconfig state. The command is only
available during the preconfig state (i.e. when the --preconfig command
line option was in use).
ERST
{
.name = "block_resize",
.args_type = "device:B,size:o",
.params = "device size",
.help = "resize a block image",
.cmd = hmp_block_resize,
.coroutine = true,
.flags = "p",
},
SRST
``block_resize``
Resize a block image while a guest is running. Usually requires guest
action to see the updated size. Resize to a lower size is supported,
but should be used with extreme caution. Note that this command only
resizes image files, it can not resize block devices like LVM volumes.
ERST
{
.name = "block_stream",
.args_type = "device:B,speed:o?,base:s?",
.params = "device [speed [base]]",
.help = "copy data from a backing file into a block device",
.cmd = hmp_block_stream,
.flags = "p",
},
SRST
``block_stream``
Copy data from a backing file into a block device.
ERST
{
.name = "block_job_set_speed",
.args_type = "device:B,speed:o",
.params = "device speed",
.help = "set maximum speed for a background block operation",
.cmd = hmp_block_job_set_speed,
.flags = "p",
},
SRST
``block_job_set_speed``
Set maximum speed for a background block operation.
ERST
{
.name = "block_job_cancel",
.args_type = "force:-f,device:B",
.params = "[-f] device",
.help = "stop an active background block operation (use -f"
"\n\t\t\t if you want to abort the operation immediately"
"\n\t\t\t instead of keep running until data is in sync)",
.cmd = hmp_block_job_cancel,
.flags = "p",
},
SRST
``block_job_cancel``
Stop an active background block operation (streaming, mirroring).
ERST
{
.name = "block_job_complete",
.args_type = "device:B",
.params = "device",
.help = "stop an active background block operation",
.cmd = hmp_block_job_complete,
.flags = "p",
},
SRST
``block_job_complete``
Manually trigger completion of an active background block operation.
For mirroring, this will switch the device to the destination path.
ERST
{
.name = "block_job_pause",
.args_type = "device:B",
.params = "device",
.help = "pause an active background block operation",
.cmd = hmp_block_job_pause,
.flags = "p",
},
SRST
``block_job_pause``
Pause an active block streaming operation.
ERST
{
.name = "block_job_resume",
.args_type = "device:B",
.params = "device",
.help = "resume a paused background block operation",
.cmd = hmp_block_job_resume,
.flags = "p",
},
SRST
``block_job_resume``
Resume a paused block streaming operation.
ERST
{
.name = "eject",
.args_type = "force:-f,device:B",
.params = "[-f] device",
.help = "eject a removable medium (use -f to force it)",
.cmd = hmp_eject,
},
SRST
``eject [-f]`` *device*
Eject a removable medium (use -f to force it).
ERST
{
.name = "drive_del",
.args_type = "id:B",
.params = "device",
.help = "remove host block device",
.cmd = hmp_drive_del,
},
SRST
``drive_del`` *device*
Remove host block device. The result is that guest generated IO is no longer
submitted against the host device underlying the disk. Once a drive has
been deleted, the QEMU Block layer returns -EIO which results in IO
errors in the guest for applications that are reading/writing to the device.
These errors are always reported to the guest, regardless of the drive's error
actions (drive options rerror, werror).
ERST
{
.name = "change",
.args_type = "device:B,force:-f,target:F,arg:s?,read-only-mode:s?",
.params = "device [-f] filename [format [read-only-mode]]",
.help = "change a removable medium, optional format, use -f to force the operation",
.cmd = hmp_change,
},
SRST
``change`` *device* *setting*
Change the configuration of a device.
``change`` *diskdevice* [-f] *filename* [*format* [*read-only-mode*]]
Change the medium for a removable disk device to point to *filename*. eg::
(qemu) change ide1-cd0 /path/to/some.iso
``-f``
forces the operation even if the guest has locked the tray.
*format* is optional.
*read-only-mode* may be used to change the read-only status of the device.
It accepts the following values:
retain
Retains the current status; this is the default.
read-only
Makes the device read-only.
read-write
Makes the device writable.
``change vnc password`` [*password*]
Change the password associated with the VNC server. If the new password
is not supplied, the monitor will prompt for it to be entered. VNC
passwords are only significant up to 8 letters. eg::
(qemu) change vnc password
Password: ********
ERST
{
.name = "screendump",
.args_type = "filename:F,format:-fs,device:s?,head:i?",
.params = "filename [-f format] [device [head]]",
.help = "save screen from head 'head' of display device 'device'"
"in specified format 'format' as image 'filename'."
"Currently only 'png' and 'ppm' formats are supported.",
.cmd = hmp_screendump,
.coroutine = true,
},
SRST
``screendump`` *filename*
Save screen into PPM image *filename*.
ERST
{
.name = "logfile",
.args_type = "filename:F",
.params = "filename",
.help = "output logs to 'filename'",
.cmd = hmp_logfile,
},
SRST
``logfile`` *filename*
Output logs to *filename*.
ERST
{
.name = "trace-event",
.args_type = "name:s,option:b,vcpu:i?",
.params = "name on|off [vcpu]",
.help = "changes status of a specific trace event "
"(vcpu: vCPU to set, default is all)",
.cmd = hmp_trace_event,
.command_completion = trace_event_completion,
},
SRST
``trace-event``
changes status of a trace event
ERST
#if defined(CONFIG_TRACE_SIMPLE)
{
.name = "trace-file",
.args_type = "op:s?,arg:F?",
.params = "on|off|flush|set [arg]",
.help = "open, close, or flush trace file, or set a new file name",
.cmd = hmp_trace_file,
},
SRST
``trace-file on|off|flush``
Open, close, or flush the trace file. If no argument is given, the
status of the trace file is displayed.
ERST
#endif
{
.name = "log",
.args_type = "items:s",
.params = "item1[,...]",
.help = "activate logging of the specified items",
.cmd = hmp_log,
},
SRST
``log`` *item1*\ [,...]
Activate logging of the specified items.
ERST
{
.name = "savevm",
.args_type = "name:s?",
.params = "tag",
.help = "save a VM snapshot. If no tag is provided, a new snapshot is created",
.cmd = hmp_savevm,
},
SRST
``savevm`` *tag*
Create a snapshot of the whole virtual machine. If *tag* is
provided, it is used as human readable identifier. If there is already
a snapshot with the same tag, it is replaced. More info at
:ref:`vm_005fsnapshots`.
Since 4.0, savevm stopped allowing the snapshot id to be set, accepting
only *tag* as parameter.
ERST
{
.name = "loadvm",
.args_type = "name:s",
.params = "tag",
.help = "restore a VM snapshot from its tag",
.cmd = hmp_loadvm,
.command_completion = loadvm_completion,
},
SRST
``loadvm`` *tag*
Set the whole virtual machine to the snapshot identified by the tag
*tag*.
Since 4.0, loadvm stopped accepting snapshot id as parameter.
ERST
{
.name = "delvm",
.args_type = "name:s",
.params = "tag",
.help = "delete a VM snapshot from its tag",
.cmd = hmp_delvm,
.command_completion = delvm_completion,
},
SRST
``delvm`` *tag*
Delete the snapshot identified by *tag*.
Since 4.0, delvm stopped deleting snapshots by snapshot id, accepting
only *tag* as parameter.
ERST
{
.name = "one-insn-per-tb",
.args_type = "option:s?",
.params = "[on|off]",
.help = "run emulation with one guest instruction per translation block",
.cmd = hmp_one_insn_per_tb,
},
SRST
``one-insn-per-tb [off]``
Run the emulation with one guest instruction per translation block.
This slows down emulation a lot, but can be useful in some situations,
such as when trying to analyse the logs produced by the ``-d`` option.
This only has an effect when using TCG, not with KVM or other accelerators.
If called with option off, the emulation returns to normal mode.
ERST
{
.name = "singlestep",
.args_type = "option:s?",
.params = "[on|off]",
.help = "deprecated synonym for one-insn-per-tb",
.cmd = hmp_one_insn_per_tb,
},
SRST
``singlestep [off]``
This is a deprecated synonym for the one-insn-per-tb command.
ERST
{
.name = "stop|s",
.args_type = "",
.params = "",
.help = "stop emulation",
.cmd = hmp_stop,
},
SRST
``stop`` or ``s``
Stop emulation.
ERST
{
.name = "cont|c",
.args_type = "",
.params = "",
.help = "resume emulation",
.cmd = hmp_cont,
},
SRST
``cont`` or ``c``
Resume emulation.
ERST
{
.name = "system_wakeup",
.args_type = "",
.params = "",
.help = "wakeup guest from suspend",
.cmd = hmp_system_wakeup,
},
SRST
``system_wakeup``
Wakeup guest from suspend.
ERST
{
.name = "gdbserver",
.args_type = "device:s?",
.params = "[device]",
.help = "start gdbserver on given device (default 'tcp::1234'), stop with 'none'",
.cmd = hmp_gdbserver,
},
SRST
``gdbserver`` [*port*]
Start gdbserver session (default *port*\=1234)
ERST
{
.name = "x",
.args_type = "fmt:/,addr:l",
.params = "/fmt addr",
.help = "virtual memory dump starting at 'addr'",
.cmd = hmp_memory_dump,
},
SRST
``x/``\ *fmt* *addr*
Virtual memory dump starting at *addr*.
ERST
{
.name = "xp",
.args_type = "fmt:/,addr:l",
.params = "/fmt addr",
.help = "physical memory dump starting at 'addr'",
.cmd = hmp_physical_memory_dump,
},
SRST
``xp /``\ *fmt* *addr*
Physical memory dump starting at *addr*.
*fmt* is a format which tells the command how to format the
data. Its syntax is: ``/{count}{format}{size}``
*count*
is the number of items to be dumped.
*format*
can be x (hex), d (signed decimal), u (unsigned decimal), o (octal),
c (char) or i (asm instruction).
*size*
can be b (8 bits), h (16 bits), w (32 bits) or g (64 bits). On x86,
``h`` or ``w`` can be specified with the ``i`` format to
respectively select 16 or 32 bit code instruction size.
Examples:
Dump 10 instructions at the current instruction pointer::
(qemu) x/10i $eip
0x90107063: ret
0x90107064: sti
0x90107065: lea 0x0(%esi,1),%esi
0x90107069: lea 0x0(%edi,1),%edi
0x90107070: ret
0x90107071: jmp 0x90107080
0x90107073: nop
0x90107074: nop
0x90107075: nop
0x90107076: nop
Dump 80 16 bit values at the start of the video memory::
(qemu) xp/80hx 0xb8000
0x000b8000: 0x0b50 0x0b6c 0x0b65 0x0b78 0x0b38 0x0b36 0x0b2f 0x0b42
0x000b8010: 0x0b6f 0x0b63 0x0b68 0x0b73 0x0b20 0x0b56 0x0b47 0x0b41
0x000b8020: 0x0b42 0x0b69 0x0b6f 0x0b73 0x0b20 0x0b63 0x0b75 0x0b72
0x000b8030: 0x0b72 0x0b65 0x0b6e 0x0b74 0x0b2d 0x0b63 0x0b76 0x0b73
0x000b8040: 0x0b20 0x0b30 0x0b35 0x0b20 0x0b4e 0x0b6f 0x0b76 0x0b20
0x000b8050: 0x0b32 0x0b30 0x0b30 0x0b33 0x0720 0x0720 0x0720 0x0720
0x000b8060: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
0x000b8070: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
0x000b8080: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
ERST
{
.name = "gpa2hva",
.args_type = "addr:l",
.params = "addr",
.help = "print the host virtual address corresponding to a guest physical address",
.cmd = hmp_gpa2hva,
},
SRST
``gpa2hva`` *addr*
Print the host virtual address at which the guest's physical address *addr*
is mapped.
ERST
#ifdef CONFIG_LINUX
{
.name = "gpa2hpa",
.args_type = "addr:l",
.params = "addr",
.help = "print the host physical address corresponding to a guest physical address",
.cmd = hmp_gpa2hpa,
},
#endif
SRST
``gpa2hpa`` *addr*
Print the host physical address at which the guest's physical address *addr*
is mapped.
ERST
{
.name = "gva2gpa",
.args_type = "addr:l",
.params = "addr",
.help = "print the guest physical address corresponding to a guest virtual address",
.cmd = hmp_gva2gpa,
},
SRST
``gva2gpa`` *addr*
Print the guest physical address at which the guest's virtual address *addr*
is mapped based on the mapping for the current CPU.
ERST
{
.name = "print|p",
.args_type = "fmt:/,val:l",
.params = "/fmt expr",
.help = "print expression value (use $reg for CPU register access)",
.cmd = hmp_print,
},
SRST
``print`` or ``p/``\ *fmt* *expr*
Print expression value. Only the *format* part of *fmt* is
used.
ERST
{
.name = "i",
.args_type = "fmt:/,addr:i,index:i.",
.params = "/fmt addr",
.help = "I/O port read",
.cmd = hmp_ioport_read,
},
SRST
``i/``\ *fmt* *addr* [.\ *index*\ ]
Read I/O port.
ERST
{
.name = "o",
.args_type = "fmt:/,addr:i,val:i",
.params = "/fmt addr value",
.help = "I/O port write",
.cmd = hmp_ioport_write,
},
SRST
``o/``\ *fmt* *addr* *val*
Write to I/O port.
ERST
{
.name = "sendkey",
.args_type = "keys:s,hold-time:i?",
.params = "keys [hold_ms]",
.help = "send keys to the VM (e.g. 'sendkey ctrl-alt-f1', default hold time=100 ms)",
.cmd = hmp_sendkey,
.command_completion = sendkey_completion,
},
SRST
``sendkey`` *keys*
Send *keys* to the guest. *keys* could be the name of the
key or the raw value in hexadecimal format. Use ``-`` to press
several keys simultaneously. Example::
sendkey ctrl-alt-f1
This command is useful to send keys that your graphical user interface
intercepts at low level, such as ``ctrl-alt-f1`` in X Window.
ERST
{
.name = "sync-profile",
.args_type = "op:s?",
.params = "[on|off|reset]",
.help = "enable, disable or reset synchronization profiling. "
"With no arguments, prints whether profiling is on or off.",
.cmd = hmp_sync_profile,
},
SRST
``sync-profile [on|off|reset]``
Enable, disable or reset synchronization profiling. With no arguments, prints
whether profiling is on or off.
ERST
{
.name = "system_reset",
.args_type = "",
.params = "",
.help = "reset the system",
.cmd = hmp_system_reset,
},
SRST
``system_reset``
Reset the system.
ERST
{
.name = "system_powerdown",
.args_type = "",
.params = "",
.help = "send system power down event",
.cmd = hmp_system_powerdown,
},
SRST
``system_powerdown``
Power down the system (if supported).
ERST
{
.name = "sum",
.args_type = "start:i,size:i",
.params = "addr size",
.help = "compute the checksum of a memory region",
.cmd = hmp_sum,
},
SRST
``sum`` *addr* *size*
Compute the checksum of a memory region.
ERST
{
.name = "device_add",
.args_type = "device:O",
.params = "driver[,prop=value][,...]",
.help = "add device, like -device on the command line",
.cmd = hmp_device_add,
.command_completion = device_add_completion,
},
SRST
``device_add`` *config*
Add device.
ERST
{
.name = "device_del",
.args_type = "id:s",
.params = "device",
.help = "remove device",
.cmd = hmp_device_del,
.command_completion = device_del_completion,
},
SRST
``device_del`` *id*
Remove device *id*. *id* may be a short ID
or a QOM object path.
ERST
{
.name = "cpu",
.args_type = "index:i",
.params = "index",
.help = "set the default CPU",
.cmd = hmp_cpu,
},
SRST
``cpu`` *index*
Set the default CPU.
ERST
{
.name = "mouse_move",
.args_type = "dx_str:s,dy_str:s,dz_str:s?",
.params = "dx dy [dz]",
.help = "send mouse move events",
.cmd = hmp_mouse_move,
},
SRST
``mouse_move`` *dx* *dy* [*dz*]
Move the active mouse to the specified coordinates *dx* *dy*
with optional scroll axis *dz*.
ERST
{
.name = "mouse_button",
.args_type = "button_state:i",
.params = "state",
.help = "change mouse button state (1=L, 2=M, 4=R)",
.cmd = hmp_mouse_button,
},
SRST
``mouse_button`` *val*
Change the active mouse button state *val* (1=L, 2=M, 4=R).
ERST
{
.name = "mouse_set",
.args_type = "index:i",
.params = "index",
.help = "set which mouse device receives events",
.cmd = hmp_mouse_set,
},
SRST
``mouse_set`` *index*
Set which mouse device receives events at given *index*, index
can be obtained with::
info mice
ERST
{
.name = "wavcapture",
.args_type = "path:F,audiodev:s,freq:i?,bits:i?,nchannels:i?",
.params = "path audiodev [frequency [bits [channels]]]",
.help = "capture audio to a wave file (default frequency=44100 bits=16 channels=2)",
.cmd = hmp_wavcapture,
},
SRST
``wavcapture`` *filename* *audiodev* [*frequency* [*bits* [*channels*]]]
Capture audio into *filename* from *audiodev*, using sample rate
*frequency* bits per sample *bits* and number of channels
*channels*.
Defaults:
- Sample rate = 44100 Hz - CD quality
- Bits = 16
- Number of channels = 2 - Stereo
ERST
{
.name = "stopcapture",
.args_type = "n:i",
.params = "capture index",
.help = "stop capture",
.cmd = hmp_stopcapture,
},
SRST
``stopcapture`` *index*
Stop capture with a given *index*, index can be obtained with::
info capture
ERST
{
.name = "memsave",
.args_type = "val:l,size:i,filename:s",
.params = "addr size file",
.help = "save to disk virtual memory dump starting at 'addr' of size 'size'",
.cmd = hmp_memsave,
},
SRST
``memsave`` *addr* *size* *file*
save to disk virtual memory dump starting at *addr* of size *size*.
ERST
{
.name = "pmemsave",
.args_type = "val:l,size:i,filename:s",
.params = "addr size file",
.help = "save to disk physical memory dump starting at 'addr' of size 'size'",
.cmd = hmp_pmemsave,
},
SRST
``pmemsave`` *addr* *size* *file*
save to disk physical memory dump starting at *addr* of size *size*.
ERST
{
.name = "boot_set",
.args_type = "bootdevice:s",
.params = "bootdevice",
.help = "define new values for the boot device list",
.cmd = hmp_boot_set,
},
SRST
``boot_set`` *bootdevicelist*
Define new values for the boot device list. Those values will override
the values specified on the command line through the ``-boot`` option.
The values that can be specified here depend on the machine type, but are
the same that can be specified in the ``-boot`` command line option.
ERST
{
.name = "nmi",
.args_type = "",
.params = "",
.help = "inject an NMI",
.cmd = hmp_nmi,
},
SRST
``nmi`` *cpu*
Inject an NMI on the default CPU (x86/s390) or all CPUs (ppc64).
ERST
{
.name = "ringbuf_write",
.args_type = "device:s,data:s",
.params = "device data",
.help = "Write to a ring buffer character device",
.cmd = hmp_ringbuf_write,
.command_completion = ringbuf_write_completion,
},
SRST
``ringbuf_write`` *device* *data*
Write *data* to ring buffer character device *device*.
*data* must be a UTF-8 string.
ERST
{
.name = "ringbuf_read",
.args_type = "device:s,size:i",
.params = "device size",
.help = "Read from a ring buffer character device",
.cmd = hmp_ringbuf_read,
.command_completion = ringbuf_write_completion,
},
SRST
``ringbuf_read`` *device*
Read and print up to *size* bytes from ring buffer character
device *device*.
Certain non-printable characters are printed ``\uXXXX``, where ``XXXX`` is the
character code in hexadecimal. Character ``\`` is printed ``\\``.
Bug: can screw up when the buffer contains invalid UTF-8 sequences,
NUL characters, after the ring buffer lost data, and when reading
stops because the size limit is reached.
ERST
{
.name = "announce_self",
.args_type = "interfaces:s?,id:s?",
.params = "[interfaces] [id]",
.help = "Trigger GARP/RARP announcements",
.cmd = hmp_announce_self,
},
SRST
``announce_self``
Trigger a round of GARP/RARP broadcasts; this is useful for explicitly
updating the network infrastructure after a reconfiguration or some forms
of migration. The timings of the round are set by the migration announce
parameters. An optional comma separated *interfaces* list restricts the
announce to the named set of interfaces. An optional *id* can be used to
start a separate announce timer and to change the parameters of it later.
ERST
{
.name = "migrate",
.args_type = "detach:-d,blk:-b,inc:-i,resume:-r,uri:s",
.params = "[-d] [-b] [-i] [-r] uri",
.help = "migrate to URI (using -d to not wait for completion)"
"\n\t\t\t -b for migration without shared storage with"
" full copy of disk\n\t\t\t -i for migration without "
"shared storage with incremental copy of disk "
"(base image shared between src and destination)"
"\n\t\t\t -r to resume a paused migration",
.cmd = hmp_migrate,
},
SRST
``migrate [-d] [-b] [-i]`` *uri*
Migrate to *uri* (using -d to not wait for completion).
``-b``
for migration with full copy of disk
``-i``
for migration with incremental copy of disk (base image is shared)
ERST
{
.name = "migrate_cancel",
.args_type = "",
.params = "",
.help = "cancel the current VM migration",
.cmd = hmp_migrate_cancel,
},
SRST
``migrate_cancel``
Cancel the current VM migration.
ERST
{
.name = "migrate_continue",
.args_type = "state:s",
.params = "state",
.help = "Continue migration from the given paused state",
.cmd = hmp_migrate_continue,
},
SRST
``migrate_continue`` *state*
Continue migration from the paused state *state*
ERST
{
.name = "migrate_incoming",
.args_type = "uri:s",
.params = "uri",
.help = "Continue an incoming migration from an -incoming defer",
.cmd = hmp_migrate_incoming,
},
SRST
``migrate_incoming`` *uri*
Continue an incoming migration using the *uri* (that has the same syntax
as the ``-incoming`` option).
ERST
{
.name = "migrate_recover",
.args_type = "uri:s",
.params = "uri",
.help = "Continue a paused incoming postcopy migration",
.cmd = hmp_migrate_recover,
},
SRST
``migrate_recover`` *uri*
Continue a paused incoming postcopy migration using the *uri*.
ERST
{
.name = "migrate_pause",
.args_type = "",
.params = "",
.help = "Pause an ongoing migration (postcopy-only)",
.cmd = hmp_migrate_pause,
},
SRST
``migrate_pause``
Pause an ongoing migration. Currently it only supports postcopy.
ERST
{
.name = "migrate_set_capability",
.args_type = "capability:s,state:b",
.params = "capability state",
.help = "Enable/Disable the usage of a capability for migration",
.cmd = hmp_migrate_set_capability,
.command_completion = migrate_set_capability_completion,
},
SRST
``migrate_set_capability`` *capability* *state*
Enable/Disable the usage of a capability *capability* for migration.
ERST
{
.name = "migrate_set_parameter",
.args_type = "parameter:s,value:s",
.params = "parameter value",
.help = "Set the parameter for migration",
.cmd = hmp_migrate_set_parameter,
.command_completion = migrate_set_parameter_completion,
},
SRST
``migrate_set_parameter`` *parameter* *value*
Set the parameter *parameter* for migration.
ERST
{
.name = "migrate_start_postcopy",
.args_type = "",
.params = "",
.help = "Followup to a migration command to switch the migration"
" to postcopy mode. The postcopy-ram capability must "
"be set on both source and destination before the "
"original migration command .",
.cmd = hmp_migrate_start_postcopy,
},
SRST
``migrate_start_postcopy``
Switch in-progress migration to postcopy mode. Ignored after the end of
migration (or once already in postcopy).
ERST
#ifdef CONFIG_REPLICATION
{
.name = "x_colo_lost_heartbeat",
.args_type = "",
.params = "",
.help = "Tell COLO that heartbeat is lost,\n\t\t\t"
"a failover or takeover is needed.",
.cmd = hmp_x_colo_lost_heartbeat,
},
#endif
SRST
``x_colo_lost_heartbeat``
Tell COLO that heartbeat is lost, a failover or takeover is needed.
ERST
{
.name = "client_migrate_info",
.args_type = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
.params = "protocol hostname port tls-port cert-subject",
.help = "set migration information for remote display",
.cmd = hmp_client_migrate_info,
},
SRST
``client_migrate_info`` *protocol* *hostname* *port* *tls-port* *cert-subject*
Set migration information for remote display. This makes the server
ask the client to automatically reconnect using the new parameters
once migration finished successfully. Only implemented for SPICE.
ERST
{
.name = "dump-guest-memory",
.args_type = "paging:-p,detach:-d,windmp:-w,zlib:-z,lzo:-l,snappy:-s,filename:F,begin:l?,length:l?",
.params = "[-p] [-d] [-z|-l|-s|-w] filename [begin length]",
.help = "dump guest memory into file 'filename'.\n\t\t\t"
"-p: do paging to get guest's memory mapping.\n\t\t\t"
"-d: return immediately (do not wait for completion).\n\t\t\t"
"-z: dump in kdump-compressed format, with zlib compression.\n\t\t\t"
"-l: dump in kdump-compressed format, with lzo compression.\n\t\t\t"
"-s: dump in kdump-compressed format, with snappy compression.\n\t\t\t"
"-w: dump in Windows crashdump format (can be used instead of ELF-dump converting),\n\t\t\t"
" for Windows x86 and x64 guests with vmcoreinfo driver only.\n\t\t\t"
"begin: the starting physical address.\n\t\t\t"
"length: the memory size, in bytes.",
.cmd = hmp_dump_guest_memory,
},
SRST
``dump-guest-memory [-p]`` *filename* *begin* *length*
\
``dump-guest-memory [-z|-l|-s|-w]`` *filename*
Dump guest memory to *protocol*. The file can be processed with crash or
gdb. Without ``-z|-l|-s|-w``, the dump format is ELF.
``-p``
do paging to get guest's memory mapping.
``-z``
dump in kdump-compressed format, with zlib compression.
``-l``
dump in kdump-compressed format, with lzo compression.
``-s``
dump in kdump-compressed format, with snappy compression.
``-w``
dump in Windows crashdump format (can be used instead of ELF-dump converting),
for Windows x64 guests with vmcoreinfo driver only
*filename*
dump file name.
*begin*
the starting physical address. It's optional, and should be
specified together with *length*.
*length*
the memory size, in bytes. It's optional, and should be specified
together with *begin*.
ERST
#if defined(TARGET_S390X)
{
.name = "dump-skeys",
.args_type = "filename:F",
.params = "",
.help = "Save guest storage keys into file 'filename'.\n",
.cmd = hmp_dump_skeys,
},
#endif
SRST
``dump-skeys`` *filename*
Save guest storage keys to a file.
ERST
#if defined(TARGET_S390X)
{
.name = "migration_mode",
.args_type = "mode:i",
.params = "mode",
.help = "Enables or disables migration mode\n",
.cmd = hmp_migrationmode,
},
#endif
SRST
``migration_mode`` *mode*
Enables or disables migration mode.
ERST
{
.name = "snapshot_blkdev",
.args_type = "reuse:-n,device:B,snapshot-file:s?,format:s?",
.params = "[-n] device [new-image-file] [format]",
.help = "initiates a live snapshot\n\t\t\t"
"of device. If a new image file is specified, the\n\t\t\t"
"new image file will become the new root image.\n\t\t\t"
"If format is specified, the snapshot file will\n\t\t\t"
"be created in that format.\n\t\t\t"
"The default format is qcow2. The -n flag requests QEMU\n\t\t\t"
"to reuse the image found in new-image-file, instead of\n\t\t\t"
"recreating it from scratch.",
.cmd = hmp_snapshot_blkdev,
},
SRST
``snapshot_blkdev``
Snapshot device, using snapshot file as target if provided
ERST
{
.name = "snapshot_blkdev_internal",
.args_type = "device:B,name:s",
.params = "device name",
.help = "take an internal snapshot of device.\n\t\t\t"
"The format of the image used by device must\n\t\t\t"
"support it, such as qcow2.\n\t\t\t",
.cmd = hmp_snapshot_blkdev_internal,
},
SRST
``snapshot_blkdev_internal``
Take an internal snapshot on device if it support
ERST
{
.name = "snapshot_delete_blkdev_internal",
.args_type = "device:B,name:s,id:s?",
.params = "device name [id]",
.help = "delete an internal snapshot of device.\n\t\t\t"
"If id is specified, qemu will try delete\n\t\t\t"
"the snapshot matching both id and name.\n\t\t\t"
"The format of the image used by device must\n\t\t\t"
"support it, such as qcow2.\n\t\t\t",
.cmd = hmp_snapshot_delete_blkdev_internal,
},
SRST
``snapshot_delete_blkdev_internal``
Delete an internal snapshot on device if it support
ERST
{
.name = "drive_mirror",
.args_type = "reuse:-n,full:-f,device:B,target:s,format:s?",
.params = "[-n] [-f] device target [format]",
.help = "initiates live storage\n\t\t\t"
"migration for a device. The device's contents are\n\t\t\t"
"copied to the new image file, including data that\n\t\t\t"
"is written after the command is started.\n\t\t\t"
"The -n flag requests QEMU to reuse the image found\n\t\t\t"
"in new-image-file, instead of recreating it from scratch.\n\t\t\t"
"The -f flag requests QEMU to copy the whole disk,\n\t\t\t"
"so that the result does not need a backing file.\n\t\t\t",
.cmd = hmp_drive_mirror,
},
SRST
``drive_mirror``
Start mirroring a block device's writes to a new destination,
using the specified target.
ERST
{
.name = "drive_backup",
.args_type = "reuse:-n,full:-f,compress:-c,device:B,target:s,format:s?",
.params = "[-n] [-f] [-c] device target [format]",
.help = "initiates a point-in-time\n\t\t\t"
"copy for a device. The device's contents are\n\t\t\t"
"copied to the new image file, excluding data that\n\t\t\t"
"is written after the command is started.\n\t\t\t"
"The -n flag requests QEMU to reuse the image found\n\t\t\t"
"in new-image-file, instead of recreating it from scratch.\n\t\t\t"
"The -f flag requests QEMU to copy the whole disk,\n\t\t\t"
"so that the result does not need a backing file.\n\t\t\t"
"The -c flag requests QEMU to compress backup data\n\t\t\t"
"(if the target format supports it).\n\t\t\t",
.cmd = hmp_drive_backup,
},
SRST
``drive_backup``
Start a point-in-time copy of a block device to a specified target.
ERST
{
.name = "drive_add",
.args_type = "node:-n,pci_addr:s,opts:s",
.params = "[-n] [[<domain>:]<bus>:]<slot>\n"
"[file=file][,if=type][,bus=n]\n"
"[,unit=m][,media=d][,index=i]\n"
"[,snapshot=on|off][,cache=on|off]\n"
"[,readonly=on|off][,copy-on-read=on|off]",
.help = "add drive to PCI storage controller",
.cmd = hmp_drive_add,
},
SRST
``drive_add``
Add drive to PCI storage controller.
ERST
{
.name = "pcie_aer_inject_error",
.args_type = "advisory_non_fatal:-a,correctable:-c,"
"id:s,error_status:s,"
"header0:i?,header1:i?,header2:i?,header3:i?,"
"prefix0:i?,prefix1:i?,prefix2:i?,prefix3:i?",
.params = "[-a] [-c] id "
"<error_status> [<tlp header> [<tlp header prefix>]]",
.help = "inject pcie aer error\n\t\t\t"
" -a for advisory non fatal error\n\t\t\t"
" -c for correctable error\n\t\t\t"
"<id> = qdev device id\n\t\t\t"
"<error_status> = error string or 32bit\n\t\t\t"
"<tlp header> = 32bit x 4\n\t\t\t"
"<tlp header prefix> = 32bit x 4",
.cmd = hmp_pcie_aer_inject_error,
},
SRST
``pcie_aer_inject_error``
Inject PCIe AER error
ERST
{
.name = "netdev_add",
.args_type = "netdev:O",
.params = "[user|tap|socket|stream|dgram|vde|bridge|hubport|netmap|vhost-user"
#ifdef CONFIG_AF_XDP
"|af-xdp"
#endif
#ifdef CONFIG_VMNET
"|vmnet-host|vmnet-shared|vmnet-bridged"
#endif
"],id=str[,prop=value][,...]",
.help = "add host network device",
.cmd = hmp_netdev_add,
.command_completion = netdev_add_completion,
.flags = "p",
},
SRST
``netdev_add``
Add host network device.
ERST
{
.name = "netdev_del",
.args_type = "id:s",
.params = "id",
.help = "remove host network device",
.cmd = hmp_netdev_del,
.command_completion = netdev_del_completion,
.flags = "p",
},
SRST
``netdev_del``
Remove host network device.
ERST
{
.name = "object_add",
.args_type = "object:S",
.params = "[qom-type=]type,id=str[,prop=value][,...]",
.help = "create QOM object",
.cmd = hmp_object_add,
.command_completion = object_add_completion,
.flags = "p",
},
SRST
``object_add``
Create QOM object.
ERST
{
.name = "object_del",
.args_type = "id:s",
.params = "id",
.help = "destroy QOM object",
.cmd = hmp_object_del,
.command_completion = object_del_completion,
.flags = "p",
},
SRST
``object_del``
Destroy QOM object.
ERST
#ifdef CONFIG_SLIRP
{
.name = "hostfwd_add",
.args_type = "arg1:s,arg2:s?",
.params = "[netdev_id] [tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport",
.help = "redirect TCP or UDP connections from host to guest (requires -net user)",
.cmd = hmp_hostfwd_add,
},
#endif
SRST
``hostfwd_add``
Redirect TCP or UDP connections from host to guest (requires -net user).
ERST
#ifdef CONFIG_SLIRP
{
.name = "hostfwd_remove",
.args_type = "arg1:s,arg2:s?",
.params = "[netdev_id] [tcp|udp]:[hostaddr]:hostport",
.help = "remove host-to-guest TCP or UDP redirection",
.cmd = hmp_hostfwd_remove,
},
#endif
SRST
``hostfwd_remove``
Remove host-to-guest TCP or UDP redirection.
ERST
{
.name = "balloon",
.args_type = "value:M",
.params = "target",
.help = "request VM to change its memory allocation (in MB)",
.cmd = hmp_balloon,
},
SRST
``balloon`` *value*
Request VM to change its memory allocation to *value* (in MB).
ERST
{
.name = "set_link",
.args_type = "name:s,up:b",
.params = "name on|off",
.help = "change the link status of a network adapter",
.cmd = hmp_set_link,
.command_completion = set_link_completion,
},
SRST
``set_link`` *name* ``[on|off]``
Switch link *name* on (i.e. up) or off (i.e. down).
ERST
{
.name = "watchdog_action",
.args_type = "action:s",
.params = "[reset|shutdown|poweroff|pause|debug|none]",
.help = "change watchdog action",
.cmd = hmp_watchdog_action,
.command_completion = watchdog_action_completion,
},
SRST
``watchdog_action``
Change watchdog action.
ERST
{
.name = "nbd_server_start",
.args_type = "all:-a,writable:-w,uri:s",
.params = "nbd_server_start [-a] [-w] host:port",
.help = "serve block devices on the given host and port",
.cmd = hmp_nbd_server_start,
.flags = "p",
},
SRST
``nbd_server_start`` *host*:*port*
Start an NBD server on the given host and/or port. If the ``-a``
option is included, all of the virtual machine's block devices that
have an inserted media on them are automatically exported; in this case,
the ``-w`` option makes the devices writable too.
ERST
{
.name = "nbd_server_add",
.args_type = "writable:-w,device:B,name:s?",
.params = "nbd_server_add [-w] device [name]",
.help = "export a block device via NBD",
.cmd = hmp_nbd_server_add,
.flags = "p",
},
SRST
``nbd_server_add`` *device* [ *name* ]
Export a block device through QEMU's NBD server, which must be started
beforehand with ``nbd_server_start``. The ``-w`` option makes the
exported device writable too. The export name is controlled by *name*,
defaulting to *device*.
ERST
{
.name = "nbd_server_remove",
.args_type = "force:-f,name:s",
.params = "nbd_server_remove [-f] name",
.help = "remove an export previously exposed via NBD",
.cmd = hmp_nbd_server_remove,
.flags = "p",
},
SRST
``nbd_server_remove [-f]`` *name*
Stop exporting a block device through QEMU's NBD server, which was
previously started with ``nbd_server_add``. The ``-f``
option forces the server to drop the export immediately even if
clients are connected; otherwise the command fails unless there are no
clients.
ERST
{
.name = "nbd_server_stop",
.args_type = "",
.params = "nbd_server_stop",
.help = "stop serving block devices using the NBD protocol",
.cmd = hmp_nbd_server_stop,
.flags = "p",
},
SRST
``nbd_server_stop``
Stop the QEMU embedded NBD server.
ERST
#if defined(TARGET_I386)
{
.name = "mce",
.args_type = "broadcast:-b,cpu_index:i,bank:i,status:l,mcg_status:l,addr:l,misc:l",
.params = "[-b] cpu bank status mcgstatus addr misc",
.help = "inject a MCE on the given CPU [and broadcast to other CPUs with -b option]",
.cmd = hmp_mce,
},
#endif
SRST
``mce`` *cpu* *bank* *status* *mcgstatus* *addr* *misc*
Inject an MCE on the given CPU (x86 only).
ERST
#ifdef CONFIG_POSIX
{
.name = "getfd",
.args_type = "fdname:s",
.params = "getfd name",
.help = "receive a file descriptor via SCM rights and assign it a name",
.cmd = hmp_getfd,
.flags = "p",
},
SRST
``getfd`` *fdname*
If a file descriptor is passed alongside this command using the SCM_RIGHTS
mechanism on unix sockets, it is stored using the name *fdname* for
later use by other monitor commands.
ERST
#endif
{
.name = "closefd",
.args_type = "fdname:s",
.params = "closefd name",
.help = "close a file descriptor previously passed via SCM rights",
.cmd = hmp_closefd,
.flags = "p",
},
SRST
``closefd`` *fdname*
Close the file descriptor previously assigned to *fdname* using the
``getfd`` command. This is only needed if the file descriptor was never
used by another monitor command.
ERST
{
.name = "block_set_io_throttle",
.args_type = "device:B,bps:l,bps_rd:l,bps_wr:l,iops:l,iops_rd:l,iops_wr:l",
.params = "device bps bps_rd bps_wr iops iops_rd iops_wr",
.help = "change I/O throttle limits for a block drive",
.cmd = hmp_block_set_io_throttle,
.flags = "p",
},
SRST
``block_set_io_throttle`` *device* *bps* *bps_rd* *bps_wr* *iops* *iops_rd* *iops_wr*
Change I/O throttle limits for a block drive to
*bps* *bps_rd* *bps_wr* *iops* *iops_rd* *iops_wr*.
*device* can be a block device name, a qdev ID or a QOM path.
ERST
{
.name = "set_password",
.args_type = "protocol:s,password:s,display:-ds,connected:s?",
.params = "protocol password [-d display] [action-if-connected]",
.help = "set spice/vnc password",
.cmd = hmp_set_password,
},
SRST
``set_password [ vnc | spice ] password [ -d display ] [ action-if-connected ]``
Change spice/vnc password. *display* can be used with 'vnc' to specify
which display to set the password on. *action-if-connected* specifies
what should happen in case a connection is established: *fail* makes
the password change fail. *disconnect* changes the password and
disconnects the client. *keep* changes the password and keeps the
connection up. *keep* is the default.
ERST
{
.name = "expire_password",
.args_type = "protocol:s,time:s,display:-ds",
.params = "protocol time [-d display]",
.help = "set spice/vnc password expire-time",
.cmd = hmp_expire_password,
},
SRST
``expire_password [ vnc | spice ] expire-time [ -d display ]``
Specify when a password for spice/vnc becomes invalid.
*display* behaves the same as in ``set_password``.
*expire-time* accepts:
``now``
Invalidate password instantly.
``never``
Password stays valid forever.
``+``\ *nsec*
Password stays valid for *nsec* seconds starting now.
*nsec*
Password is invalidated at the given time. *nsec* are the seconds
passed since 1970, i.e. unix epoch.
ERST
{
.name = "chardev-add",
.args_type = "args:s",
.params = "args",
.help = "add chardev",
.cmd = hmp_chardev_add,
.command_completion = chardev_add_completion,
},
SRST
``chardev-add`` *args*
chardev-add accepts the same parameters as the -chardev command line switch.
ERST
{
.name = "chardev-change",
.args_type = "id:s,args:s",
.params = "id args",
.help = "change chardev",
.cmd = hmp_chardev_change,
},
SRST
``chardev-change`` *args*
chardev-change accepts existing chardev *id* and then the same arguments
as the -chardev command line switch (except for "id").
ERST
{
.name = "chardev-remove",
.args_type = "id:s",
.params = "id",
.help = "remove chardev",
.cmd = hmp_chardev_remove,
.command_completion = chardev_remove_completion,
},
SRST
``chardev-remove`` *id*
Removes the chardev *id*.
ERST
{
.name = "chardev-send-break",
.args_type = "id:s",
.params = "id",
.help = "send a break on chardev",
.cmd = hmp_chardev_send_break,
.command_completion = chardev_remove_completion,
},
SRST
``chardev-send-break`` *id*
Send a break on the chardev *id*.
ERST
{
.name = "qemu-io",
.args_type = "qdev:-d,device:B,command:s",
.params = "[-d] [device] \"[command]\"",
.help = "run a qemu-io command on a block device\n\t\t\t"
"-d: [device] is a device ID rather than a "
"drive ID or node name",
.cmd = hmp_qemu_io,
},
SRST
``qemu-io`` *device* *command*
Executes a qemu-io command on the given block device.
ERST
{
.name = "qom-list",
.args_type = "path:s?",
.params = "path",
.help = "list QOM properties",
.cmd = hmp_qom_list,
.flags = "p",
},
SRST
``qom-list`` [*path*]
Print QOM properties of object at location *path*
ERST
{
.name = "qom-get",
.args_type = "path:s,property:s",
.params = "path property",
.help = "print QOM property",
.cmd = hmp_qom_get,
.flags = "p",
},
SRST
``qom-get`` *path* *property*
Print QOM property *property* of object at location *path*
ERST
{
.name = "qom-set",
.args_type = "json:-j,path:s,property:s,value:S",
.params = "[-j] path property value",
.help = "set QOM property.\n\t\t\t"
"-j: the value is specified in json format.",
.cmd = hmp_qom_set,
.flags = "p",
},
SRST
``qom-set`` *path* *property* *value*
Set QOM property *property* of object at location *path* to value *value*
ERST
{
.name = "replay_break",
.args_type = "icount:l",
.params = "icount",
.help = "set breakpoint at the specified instruction count",
.cmd = hmp_replay_break,
},
SRST
``replay_break`` *icount*
Set replay breakpoint at instruction count *icount*.
Execution stops when the specified instruction is reached.
There can be at most one breakpoint. When breakpoint is set, any prior
one is removed. The breakpoint may be set only in replay mode and only
"in the future", i.e. at instruction counts greater than the current one.
The current instruction count can be observed with ``info replay``.
ERST
{
.name = "replay_delete_break",
.args_type = "",
.params = "",
.help = "remove replay breakpoint",
.cmd = hmp_replay_delete_break,
},
SRST
``replay_delete_break``
Remove replay breakpoint which was previously set with ``replay_break``.
The command is ignored when there are no replay breakpoints.
ERST
{
.name = "replay_seek",
.args_type = "icount:l",
.params = "icount",
.help = "replay execution to the specified instruction count",
.cmd = hmp_replay_seek,
},
SRST
``replay_seek`` *icount*
Automatically proceed to the instruction count *icount*, when
replaying the execution. The command automatically loads nearest
snapshot and replays the execution to find the desired instruction.
When there is no preceding snapshot or the execution is not replayed,
then the command fails.
*icount* for the reference may be observed with ``info replay`` command.
ERST
{
.name = "calc_dirty_rate",
.args_type = "dirty_ring:-r,dirty_bitmap:-b,second:l,sample_pages_per_GB:l?",
.params = "[-r] [-b] second [sample_pages_per_GB]",
.help = "start a round of guest dirty rate measurement (using -r to"
"\n\t\t\t specify dirty ring as the method of calculation and"
"\n\t\t\t -b to specify dirty bitmap as method of calculation)",
.cmd = hmp_calc_dirty_rate,
},
SRST
``calc_dirty_rate`` *second*
Start a round of dirty rate measurement with the period specified in *second*.
The result of the dirty rate measurement may be observed with ``info
dirty_rate`` command.
ERST
{
.name = "set_vcpu_dirty_limit",
.args_type = "dirty_rate:l,cpu_index:l?",
.params = "dirty_rate [cpu_index]",
.help = "set dirty page rate limit, use cpu_index to set limit"
"\n\t\t\t\t\t on a specified virtual cpu",
.cmd = hmp_set_vcpu_dirty_limit,
},
SRST
``set_vcpu_dirty_limit``
Set dirty page rate limit on virtual CPU, the information about all the
virtual CPU dirty limit status can be observed with ``info vcpu_dirty_limit``
command.
ERST
{
.name = "cancel_vcpu_dirty_limit",
.args_type = "cpu_index:l?",
.params = "[cpu_index]",
.help = "cancel dirty page rate limit, use cpu_index to cancel"
"\n\t\t\t\t\t limit on a specified virtual cpu",
.cmd = hmp_cancel_vcpu_dirty_limit,
},
SRST
``cancel_vcpu_dirty_limit``
Cancel dirty page rate limit on virtual CPU, the information about all the
virtual CPU dirty limit status can be observed with ``info vcpu_dirty_limit``
command.
ERST
{
.name = "info",
.args_type = "item:s?",
.params = "[subcommand]",
.help = "show various information about the system state",
.cmd = hmp_info_help,
.sub_table = hmp_info_cmds,
.flags = "p",
},
#if defined(CONFIG_FDT)
{
.name = "dumpdtb",
.args_type = "filename:F",
.params = "filename",
.help = "dump the FDT in dtb format to 'filename'",
.cmd = hmp_dumpdtb,
},
SRST
``dumpdtb`` *filename*
Dump the FDT in dtb format to *filename*.
ERST
#endif
#if defined(CONFIG_XEN_EMU)
{
.name = "xen-event-inject",
.args_type = "port:i",
.params = "port",
.help = "inject event channel",
.cmd = hmp_xen_event_inject,
},
SRST
``xen-event-inject`` *port*
Notify guest via event channel on port *port*.
ERST
{
.name = "xen-event-list",
.args_type = "",
.params = "",
.help = "list event channel state",
.cmd = hmp_xen_event_list,
},
SRST
``xen-event-list``
List event channels in the guest
ERST
#endif
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