Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* microvm docs and fixes (Sergio, Liam)
* New processor features for Intel errata (myself, Pawan)
* Kconfig fixes (myself, Thomas)
* Revert mc146818rtc change (myself)
* Deprecate scsi-disk (myself)
* RTC fix (myself, Marcelo)

# gpg: Signature made Tue 19 Nov 2019 09:03:49 GMT
# gpg:                using RSA key BFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  mc146818rtc: fix timer interrupt reinjection again
  Revert "mc146818rtc: fix timer interrupt reinjection"
  scsi: deprecate scsi-disk
  hw/i386: Move save_tsc_khz from PCMachineClass to X86MachineClass
  docs/microvm.rst: add instructions for shutting down the guest
  docs/microvm.rst: fix alignment in "Limitations"
  vfio: vfio-pci requires EDID
  hw/i386: Fix compiler warning when CONFIG_IDE_ISA is disabled
  target/i386: Export TAA_NO bit to guests
  target/i386: add PSCHANGE_NO bit for the ARCH_CAPABILITIES MSR
  microvm: fix memory leak in microvm_fix_kernel_cmdline
  scripts: Detect git worktrees for get_maintainer.pl --git

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 24 insertions, 3 deletions

diff --git a/docs/microvm.rst b/docs/microvm.rst
index aae811a922..fcf41fc1f6 100644
--- a/docs/microvm.rst
+++ b/docs/microvm.rst
@@ -33,9 +33,9 @@ Limitations
 
 Currently, microvm does *not* support the following features:
 
- - PCI-only devices.
- - Hotplug of any kind.
- - Live migration across QEMU versions.
+- PCI-only devices.
+- Hotplug of any kind.
+- Live migration across QEMU versions.
 
 
 Using the microvm machine type
@@ -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.