File kvm-supported.txt of Package qemu-linux-user.5922

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File kvm-supported.txt of Package qemu-linux-user.5922

SLES 12 SP1 QEMU/KVM RELATED SUPPORT STATEMENTS

Overview
--------

The QEMU packages included with SLES 12 SP1 provide a large variety of
  features, from the very latest customer requests to features of questionable
  quality or value. This document was created to assist the user in deciding
  which features can be relied upon to build enterprise class virtualization
  solutions. KVM virtualization for the System z host (s390x) is provided as a
  technology preview while on x86 support is offered at the L3 (full support)
  level.

KVM is implemented as linux kernel modules, which enables the linux kernel to
  function as an integral part of the KVM hypervisor. The hypervisor-guest
  interaction is controlled by QEMU through the /dev/kvm ioctl interface. The
  linux host assists in the virtualization of storage, networking and display
  resources as well as direct hardware passthrough of PCI and USB devices. Linux
  memory and cpu management features are used by both KVM and QEMU to enable
  guests to share host resources as efficiently as possible.

QEMU is a primary component of KVM based virtualization. The legacy qemu-kvm
  program is provided for continuity with pre SLES 12 usage, including in
  libvirt xml references. The QEMU emulator binaries qemu-system-x86_64 and
  qemu-system-i386 (x86 host) and qemu-system-s390x (System z host) are now the
  primary programs to use to enable KVM virtualization. When using these
  programs, the -machine option accel=kvm (or its alias -enable-kvm) must be
  specified for KVM accelation to be active.

Libvirt is the preferred means of accessing QEMU/KVM functionality. This
  document focuses on the features and direct usage of QEMU/KVM. Refer to other
  documentation for libvirt and libvirt based tools usage.

Major QEMU/KVM Supported Features
---------------------------------

- KVM virtualization is accomplished by using the QEMU program in KVM
  acceleration mode. KVM acceleration requires that both guest and host have
  the same fundamental architecture.

- Guest images created under previous QEMU versions are supported through
  machine types which match up with these previous versions.

- For ease of use, the QEMU program has defaults which represent traditional
  usage patterns.

- Guest virtual machine characteristics are specified by a combination of
  internal defaults, given on the QEMU program command-line, and optional config
  files. Run-time control is done through either through the Human Monitor
  "Protocol" (HMP), or the JSON based programmatical QEMU Monitor Protocol
  (QMP) interface. Since a KVM guest runs in the context of a normal linux
  process, some types of execution controls are managed with normal linux tools.

- Various standard vCPU types are available, along with the ability to specify
  specific CPU features visible to the guest.

- QEMU incorporates a SEABIOS based system BIOS and iPXE based PXE ROMs which
  allow boot options common to PC's along with other features tailored to
  virtualization. Various VGABIOS ROMs (also from the SEABIOS project) are also
  included.

- Some QEMU messages have been localized to various languages. This is provided
  by the qemu-lang package. Keyboard mappings for various nationalities is also
  provided.

- Virtual machine lifecycle controls include startup through the system bios or
  using kernel boot, ACPI or legacy based shutdown, execution pausing, and the
  saving and restoring of machine state. Two varieties of "monitors" are
  provided for controlling runtime aspects of the VM: the human monitor, and a
  JSON based QMP (See /usr/share/doc/packages/kvm/qmp-commands.txt).

- Guest execution state may be "moved" in both time (save/restore) and space
  (static and live migration). Guest migration from SLES 12 GA to SLES 12 SP1
  hosts is supported.

- Security considerations include secccomp2 based sandboxing, vTPM, privileged
  helpers and security models for executing QEMU as non-root users.

- QEMU is able to run a wide range of common operating systems as guests. See
  the online SUSE documentation for supported OS's. Windows guests can
  optionally be accelerated with QEMU/KVM provided Hyper-V hypercalls, or with
  paravirtual drivers from the SUSE Virtual Machine Driver Pack.

- QEMU provides best effort reuse of existing disk images, including those with
  systems installed, through geometry probing. Also disk images produced by
  other popular virtualization technologies may be imported into QEMU supported
  storage formats. These QEMU formats include features which exploit the
  benefits of virtualization.

- Memory, cpu and disk space overcommit are possible and can be beneficial when
  done responsibly. Additional management of these resources comes in the form
  of memory ballooning, Host KSM, vcpu hot-add, online disk resizing, trim,
  discard and hole punching.

- Guest performance is enhanced through the use of virtio devices, various disk
  caching modes, network acceleration via the vhost-net kernel module including
  zero copy optimizations, multiqueue network transmit capabilities, host
  transparent huge pages (THP) and direct hugetlb usage. Physical PCI and USB
  devices may also be passed through to the guest, including SR-IOV VF's.

- The guest's UI is accessable via GTK, SDL, VNC, Spice, and serial (including
  curses TUI) interfaces.

- Guest timekeeping is supported in a variety of ways, including a paravirtual
  clocksource, and options for the various guest clocks for how to handle the
  timeslicing of the guest's execution on the host.

- Guest OS's interact with virtualized hardware including a choice of either
  older or more recent x86 system chipsets, system devices and buses, and a
  variety of common storage and networking emulated devices. SMBIOS and ACPI
  table details can be customized. Virtio based para-virtual devices are
  available for more efficient I/O.

- In addition to the para-virtualized devices already mentioned, other devices
  and infrastructure designed to avoid virtualization "problem areas" are
  available such as SPICE graphics, vmmouse emulation and tablet style pointer
  interfaces.

- A built-in user-mode network (SLIRP) stack is available.

- Portions of the host file system may be shared with a guest by using virtFS.

- A guest "agent" is available for SLES 12 SP1 KVM guests (see qemu-guest-agent
  package). This allows some introspection and control of the guest OS
  environment from the host.

- The following features were previously in a technology preview status, but are
  now fully supported:
  - virtio-blk-dataplane has now been fully integrated with the block subsystem.
  - RADOS Block Devices (RBD)

QEMU/KVM Technology Previews
----------------------------

- KVM on System z using the qemu-system-s390x system emulator is not yet fully
  supported. Other support statements made throughout this document generally
  refer to x86 usage only.

- Specifying and placing PCI devices on a PCI bridge allows for a greater number
  of devices.

- Nested VMX and SVM virtualization is possible.

- virtio-blk-data-plane allows higher block I/O rates

Noteworthy QEMU/KVM Unsupported Features
----------------------------------------

- Note that some features are unsupported simply due to lack of validation. If
  an existing feature is desired, but not marked supported, let SUSE know about
  your requirements.

- The TCG "acceleration" mode may be helpful for problem isolation, but
  otherwise presents insufficient benefit and stability.

- Use of -cpu host is not supported in all host/guest configurations.

- ISCSI integration is not enabled in QEMU. It is however possible for guests to
  access iSCSI targets available to the host via the blockio interfaces.

- GlusterFS integration is not enabled.

Deprecated, Superseded, Modified and Dropped Features
-------------------------------------------

- When no video adapter is specified, the default used is stdvga. This differs
  from the default of prior releases which was cirrus. The cirrus adapter was
  considered too outdated to continue to use as the default.

- The deprecated windows drivers (win-virtio-drivers.iso) are no longer provided.
  The Virtual Machine Driver Pack is the supported way to get virtio drivers for
  Windows guests.

- The use of ",boot=on" for virtio disks is no longer needed since the bios used
  supports the virtio block interface directly. In fact, its usage may cause
  problems, and is now considered deprecated.

- The use of "?" as a parameter to "-cpu", "-soundhw", "-device", "-M",
  "-machine", "-d", and "-clock" is now considered deprecated. Use "help"
  instead.

- Passthrough of a host floppy device is now considered deprecated.

- Use of aio=native without direct cache mode also being specified is now
  considered deprecated. (It has no effect in this case).

- The use of image encryption in qcow and qcow2 formats is now considered deprecated.
  Analysis has shown it to be weak encryption, in addition to suffering from poor
  design. Images can easily be converted to a non-encrypted format.

- Use of acpi, boot-opts, and smp-opts in a -readconfig config file are now
  considered deprecated. In the future those names will be standardized to
  acpitable, boot, and smp respectively.

- When only a partial SMP topology is provided (ie only some of sockets, cores,
  threads) the derived guest ABI is not guaranteed to be equivalent in future
  versions.

- These previously supported command line options are no longer recognized:
  -device pc-sysfw (no longer needed)

- The previously supported blkdev-add QMP command has been flagged as lacking
  and could possibly change syntax in the future.

- These previously unsupported command line options are now deprecated:
  -no-kvm-irqchip (use -machine kernel_irqchip=off instead)
  -no-kvm-pit
  -no-kvm-pit-reinjection
  -tdf

- The case of specified sockets, cores, and threads not matching the vcpu count
  is no longer silently ignored. QEMU now requires that the topology to match up
  with the vcpu count.

- These previously unsupported command line options are no longer recognized:
  -device cfi.pflash01
  -device esp
  -device exynos4210-ehci-usb
  -device fusbh200-ehci-usb
  -device icc-bridge
  -device q35-pcihost
  -device mch
  -device smbus-eeprom
  -device SUNW,fdtwo
  -device sysbus-ahci
  -device sysbus-fdc
  -device sysbus-ohci
  -device tegra2-ehci-usb
  -device testdev (use -device pc-testdev instead)
  -device virtio-mmio
  -device xln,ps7-usb
  -enable-nesting
  -kvm-shadow-memory (use -machine kvm_shadow_mem= instead)
  -M mac
  -nvram
  -old-param
  -osk
  -pcidevice (use -device pci-assign or vfio-pci instead)
  -qtest
  -semihosting

- These previously supported monitor commands are no longer recognized:
  pci_add (use device_add instead)
  pci_del (use device_del instead)

- These previously unsupported monitor commands are no longer recognized:
  cpu_set

- Legacy pci passthrough (using -device pci-assign or kvm-pci-assign) is now
  considered deprecated, as the next SLE 12 service pack will include a kernel
  version where the required KVM support is deprecated, and lagging behind vfio
  in many aspects. Switching to vfio should have minimal impact for the user.

QEMU Command-Line and Monitor Syntax and Support
------------------------------------------------

- The QEMU program command-line syntax is as follows:
  qemu-system-i386 [options] [disk_image]
  qemu-system-s390x [options]
  qemu-system-x86_64 [options] [disk_image]

Where 'options' are taken from the options listed below, and 'disk_image' is
  the file system reference to the the x86 guest's primary IDE based hard disk
  image. This image as well as those used with -drive or -cdrom, may be in the
  raw (no format), qcow2 or qed storage formats, and may be located in files
  within the host filesystem, logical volumes, host physical disks, or network
  based storage. Read only media may also be accessed via URL style protocol
  specifiers.

Note that as a general rule, as new command line options are added which serve
  to replace an older option or interface, you are strongly encouraged to adapt
  your usage to the new option. The new option is being introduced to provide
  better functionality and usability going forward. In some cases existing
  problems or even bugs in older interfaces cannot be fixed due to functional
  expectations, but are resolved in the newer interface or option.
  This advice includes moving to the most recent machine type (eg pc-i440fx-2.3
  instead of pc-i440fx-2.0) if possible.

- The following monitor commands are supported:
  ?
  balloon target ...
  block_resize ...
  boot_set ...
  [c|cont]
  change device ...
  chardev-add ...
  chardev-remove ...
  cpu ...
  cpu-add ...
  delvm ...
  device_add ...
  device_del ...
  drive_add ...
  drive_backup ...
  drive_del ...
  dump_guest_memory ...
  eject ...
  gdbserver ...
  help
  info ...
  loadvm ...
  logfile ...
  logitem ...
  mce ...
  memsave ...
  migrate ...
  migrate_cancel
  migrate_incoming
  migrate_set_cache_size ...
  migrate_set_capability ...
  migrate_set_downtime ...
  migrate_set_speed ...
  mouse_button ...
  mouse_move ...
  mouse_set ...
  nmi ...
  object_add ...
  object_del ...
  pci_add ...
  pci_del...
  pmemsave ...
  [p|print] ...
  q
  qemu-io ...
  qom-list
  qom-set
  ringbuf_read ...
  ringbuf_write ...
  savevm ...
  sendkey ...
  snapshot_blkdev_internal ...
  snapshot_delete_blkdev_internal ...
  stop
  system_powerdown
  system_reset
  system_wakeup
  usb_add ...
  usb_del ...
  watchdog_action ...
  x ...
  xp ...

- The following monitor commands are unsupported:
  acl_add ...
  acl_policy ...
  acl_remove ...
  acl_reset ...
  acl_show ...
  block_job_cancel ...
  block_job_complete ...
  block_job_pause ...
  block_job_resume ...
  block_job_set_speed ...
  block_passwd ...
  client_migrate_info ...
  close_fd ...
  commit ...
  drive_mirror ...
  expire_password ...
  hostfwd_add ...
  hostfwd_remove ...
  host_net_add ...
  host_net_remove ...
  i ...
  nbd_server_add ...
  nbd server_start ...
  nbd_server_stop ...
  netdev_add
  netdev_del ...
  o ...
  pcie_aer_inject_error ...
  screendump ...
  set_link ...
  set_password ...
  singlestep ...
  snapshot_blkdev ...
  stopcapture ...
  sum ...
  trace_event ...
  wavcapture ...

- The following QMP commands are supported:
  add_client
  add-fd
  balloon
  block-commit
  blockdev-snapshot-delete-internal-sync
  blockdev-snapshot-internal-sync
  blockdev-snapshot-sync
  block_passwd
  block_resize
  block_set_io_throttle
  block-set-write-threshold
  block_stream
  change
  change-vnc-password
  chardev-add
  chardev-remove
  client_migrate_info
  closefd
  cont
  cpu
  cpu-add
  device_add
  device_del
  device-list-properties
  dump-guest-memory
  eject
  expire_password
  getfd
  human-monitor-command
  inject-nmi
  memsave
  migrate
  migrate_cancel
  migrate-incoming
  migrate-set-cache-size
  migrate-set-capabilities
  migrate_set_downtime
  migrate_set_speed
  object-add
  object-del
  pmemsave
  qmp_capabilities
  qom-get
  qom-list
  qom-list-types
  qom-set
  query-acpi-ospm-status
  query-balloon
  query-block
  query-block-jobs
  query-blockstats
  query-chardev
  query-chardev-backends
  query-command-line-options
  query-commands
  query-cpu-definitions
  query-cpus
  query-dump-guest-memory-capability
  query-events
  query-fdsets
  query-iothreads
  query-kvm
  query-machines
  query-memdev
  query-memory-devices
  query-mice
  query-migrate
  query-migrate-cache-size
  query-migrate-capabilities
  query-name
  query-named-block-nodes
  query-pci
  query-rx-filter
  query-spice
  query-status
  query-target
  query-tpm
  query-tpm-models
  query-tpm-types
  query-uuid
  query-version
  query-vnc
  quit
  remove-fd
  ringbuf-read
  ringbuf-write
  rtc-reset-reinjection
  screendump
  send-key
  set_link
  set_password
  stop
  system_powerdown
  system_reset
  system_wakeup
  trace-event-get-state
  trace-event-set-state
  transaction
  xen-save-devices-state
  xen-set-global-dirty-log

- The following QMP commands are unsupported:
  blockdev-add
  blockdev-backup
  block-job-cancel
  block-job-complete
  block-job-pause
  block-job-resume
  block-job-set-speed
  change-backing-file
  drive-backup
  drive-mirror
  netdev_add
  netdev_del
  nbd-server-add
  nbd-server-start
  nbd-server-stop
  x-input-send-event

Places

File kvm-supported.txt of Package qemu-linux-user.5922

Places