[2/2] docs/microvm.rst: add instructions for shutting down the guest
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Message ID 20191115161338.42864-3-slp@redhat.com
State New
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Series
  • docs/microvm.rst: fix alignment and explain shut down
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Commit Message

Sergio Lopez Nov. 15, 2019, 4:13 p.m. UTC
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>
---
 docs/microvm.rst | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

Comments

Paolo Bonzini Nov. 15, 2019, 4:26 p.m. UTC | #1
On 15/11/19 17:13, Sergio Lopez wrote:
> 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>
> ---
>  docs/microvm.rst | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/docs/microvm.rst b/docs/microvm.rst
> index 4cf84746b9..fcf41fc1f6 100644
> --- a/docs/microvm.rst
> +++ b/docs/microvm.rst
> @@ -106,3 +106,24 @@ disabled::
>       -device virtio-blk-device,drive=test \
>       -netdev tap,id=tap0,script=no,downscript=no \
>       -device virtio-net-device,netdev=tap0
> +
> +
> +Triggering a guest-initiated shut down
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +As the microvm machine type includes just a small set of system
> +devices, some x86 mechanisms for rebooting or shutting down the
> +system, like sending a key sequence to the keyboard or writing to an
> +ACPI register, doesn't have any effect in the VM.
> +
> +The recommended way to trigger a guest-initiated shut down is by
> +generating a ``triple-fault``, which will cause the VM to initiate a
> +reboot. Additionally, if the ``-no-reboot`` argument is present in the
> +command line, QEMU will detect this event and terminate its own
> +execution gracefully.
> +
> +Linux does support this mechanism, but by default will only be used
> +after other options have been tried and failed, causing the reboot to
> +be delayed by a small number of seconds. It's possible to instruct it
> +to try the triple-fault mechanism first, by adding ``reboot=t`` to the
> +kernel's command line.
> 

Queued, thanks.

Paolo

Patch
diff mbox series

diff --git a/docs/microvm.rst b/docs/microvm.rst
index 4cf84746b9..fcf41fc1f6 100644
--- a/docs/microvm.rst
+++ b/docs/microvm.rst
@@ -106,3 +106,24 @@  disabled::
      -device virtio-blk-device,drive=test \
      -netdev tap,id=tap0,script=no,downscript=no \
      -device virtio-net-device,netdev=tap0
+
+
+Triggering a guest-initiated shut down
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+As the microvm machine type includes just a small set of system
+devices, some x86 mechanisms for rebooting or shutting down the
+system, like sending a key sequence to the keyboard or writing to an
+ACPI register, doesn't have any effect in the VM.
+
+The recommended way to trigger a guest-initiated shut down is by
+generating a ``triple-fault``, which will cause the VM to initiate a
+reboot. Additionally, if the ``-no-reboot`` argument is present in the
+command line, QEMU will detect this event and terminate its own
+execution gracefully.
+
+Linux does support this mechanism, but by default will only be used
+after other options have been tried and failed, causing the reboot to
+be delayed by a small number of seconds. It's possible to instruct it
+to try the triple-fault mechanism first, by adding ``reboot=t`` to the
+kernel's command line.