jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
docs/microvm.rst: add instructions for shutting down the guest
Add a new section explaining the particularities of the microvm
machine type for triggering a guest-initiated shut down.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Message-Id: <20191115161338.42864-3-slp@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
authored by
Sergio Lopez
and committed by
Paolo Bonzini
62e9dc35
ff9d7089
+21
+21
docs/microvm.rst
+21
docs/microvm.rst
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-device virtio-blk-device,drive=test \
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-netdev tap,id=tap0,script=no,downscript=no \
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-device virtio-net-device,netdev=tap0
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Triggering a guest-initiated shut down
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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As the microvm machine type includes just a small set of system
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devices, some x86 mechanisms for rebooting or shutting down the
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system, like sending a key sequence to the keyboard or writing to an
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ACPI register, doesn't have any effect in the VM.
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The recommended way to trigger a guest-initiated shut down is by
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generating a ``triple-fault``, which will cause the VM to initiate a
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reboot. Additionally, if the ``-no-reboot`` argument is present in the
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command line, QEMU will detect this event and terminate its own
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execution gracefully.
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Linux does support this mechanism, but by default will only be used
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after other options have been tried and failed, causing the reboot to
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be delayed by a small number of seconds. It's possible to instruct it
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to try the triple-fault mechanism first, by adding ``reboot=t`` to the
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kernel's command line.