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In rST markup, single backticks `like this` represent "interpreted text", which can be handled as a bunch of different things if tagged with a specific "role": https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#interpreted-text (the most common one for us is "reference to a URL, which gets hyperlinked"). The default "role" if none is specified is "title_reference", intended for references to book or article titles, and it renders into the HTML as <cite>...</cite> (usually comes out as italics). This commit fixes various places in the manual which were using single backticks when double backticks (for literal text) were intended, and covers those files where only one or two instances of these errors were made. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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===================
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Virtual CPU hotplug
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===================
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A complete example of vCPU hotplug (and hot-unplug) using QMP
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``device_add`` and ``device_del``.
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vCPU hotplug
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------------
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(1) Launch QEMU as follows (note that the "maxcpus" is mandatory to
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allow vCPU hotplug)::
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$ qemu-system-x86_64 -display none -no-user-config -m 2048 \
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-nodefaults -monitor stdio -machine pc,accel=kvm,usb=off \
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-smp 1,maxcpus=2 -cpu IvyBridge-IBRS \
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-qmp unix:/tmp/qmp-sock,server=on,wait=off
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(2) Run 'qmp-shell' (located in the source tree, under: "scripts/qmp/)
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to connect to the just-launched QEMU::
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$> ./qmp-shell -p -v /tmp/qmp-sock
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[...]
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(QEMU)
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(3) Find out which CPU types could be plugged, and into which sockets::
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(QEMU) query-hotpluggable-cpus
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{
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"execute": "query-hotpluggable-cpus",
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"arguments": {}
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}
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{
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"return": [
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{
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"type": "IvyBridge-IBRS-x86_64-cpu",
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"vcpus-count": 1,
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"props": {
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"socket-id": 1,
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"core-id": 0,
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"thread-id": 0
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}
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},
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{
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"qom-path": "/machine/unattached/device[0]",
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"type": "IvyBridge-IBRS-x86_64-cpu",
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"vcpus-count": 1,
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"props": {
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"socket-id": 0,
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"core-id": 0,
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"thread-id": 0
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}
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}
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]
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}
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(QEMU)
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(4) The ``query-hotpluggable-cpus`` command returns an object for CPUs
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that are present (containing a "qom-path" member) or which may be
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hot-plugged (no "qom-path" member). From its output in step (3), we
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can see that ``IvyBridge-IBRS-x86_64-cpu`` is present in socket 0,
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while hot-plugging a CPU into socket 1 requires passing the listed
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properties to QMP ``device_add``::
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(QEMU) device_add id=cpu-2 driver=IvyBridge-IBRS-x86_64-cpu socket-id=1 core-id=0 thread-id=0
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{
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"execute": "device_add",
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"arguments": {
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"socket-id": 1,
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"driver": "IvyBridge-IBRS-x86_64-cpu",
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"id": "cpu-2",
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"core-id": 0,
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"thread-id": 0
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}
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}
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{
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"return": {}
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}
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(QEMU)
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(5) Optionally, run QMP ``query-cpus-fast`` for some details about the
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vCPUs::
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(QEMU) query-cpus-fast
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{
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"execute": "query-cpus-fast",
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"arguments": {}
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}
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{
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"return": [
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{
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"qom-path": "/machine/unattached/device[0]",
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"target": "x86_64",
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"thread-id": 11534,
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"cpu-index": 0,
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"props": {
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"socket-id": 0,
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"core-id": 0,
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"thread-id": 0
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},
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"arch": "x86"
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},
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{
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"qom-path": "/machine/peripheral/cpu-2",
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"target": "x86_64",
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"thread-id": 12106,
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"cpu-index": 1,
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"props": {
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"socket-id": 1,
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"core-id": 0,
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"thread-id": 0
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},
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"arch": "x86"
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}
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]
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}
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(QEMU)
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vCPU hot-unplug
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---------------
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From the 'qmp-shell', invoke the QMP ``device_del`` command::
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(QEMU) device_del id=cpu-2
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{
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"execute": "device_del",
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"arguments": {
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"id": "cpu-2"
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}
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}
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{
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"return": {}
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}
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(QEMU)
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.. note::
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vCPU hot-unplug requires guest cooperation; so the ``device_del``
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command above does not guarantee vCPU removal -- it's a "request to
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unplug". At this point, the guest will get a System Control
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Interrupt (SCI) and calls the ACPI handler for the affected vCPU
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device. Then the guest kernel will bring the vCPU offline and tell
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QEMU to unplug it.
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