acrn-hypervisor/devicemodel
Wu Zhou 262a48f346 dm: vm_event: add support for RTC change event
When a guest OS performs an RTC change action, we wish this event be
captured by developers, and then they can decide what to do with it.
(e.g., whether to change physical RTC)

There are some facts that makes RTC change event a bit complicated:
- There are 7 RTC date/time regs (year, month…). They can only be
  updated one by one.
- RTC time is not reliable before date/time update is finished.
- Guests can update RTC date/time regs in any order.
- Guests may update RTC date/time regs during either RTC halted or not
  halted.

A single date/time update event is not reliable. We have to wait for
the guest to finish the update process. So the DM's event handler
sets up a timer, and wait for some time (1 second). If no more change
happens befor the timer expires, we can conclude that the RTC
change has been done. Then the rtc change event is emitted.

This logic of event handler can be used to process HV vrtc time change
event too.

Tracked-On: #8547
Signed-off-by: Wu Zhou <wu.zhou@intel.com>
Reviewed-by: Jian Jun Chen <jian.jun.chen@intel.com>
2024-02-01 17:01:31 +08:00
..
arch/x86 devicemodel: Fix spelling and grammar mistakes. 2023-09-08 08:01:13 +08:00
bios OVMF release v3.0 2022-03-31 09:06:34 +08:00
core dm: vm_event: add support for RTC change event 2024-02-01 17:01:31 +08:00
hw dm: vm_event: add support for RTC change event 2024-02-01 17:01:31 +08:00
include dm: vm_event: add support for RTC change event 2024-02-01 17:01:31 +08:00
lib Update copyright year range in code headers 2022-07-15 11:48:35 +08:00
log Update copyright year range in code headers 2022-07-15 11:48:35 +08:00
Makefile dm: vm_event: init vm_event 2024-02-01 17:01:31 +08:00
README.rst doc: terminology cleanup in DM readme 2021-11-24 06:29:25 -08:00
samples acrn-config: Reorg config tool folder 2021-01-27 11:08:28 +08:00

README.rst

ACRN Device Model
#################

Introduction
============

The ACRN Device Model provides **device sharing** capabilities between the
Service VM and post-launched User VMs. It is a component that is used in
conjunction with the `ACRN Hypervisor`_ and is installed within the Service
VM.

.. _`ACRN Hypervisor`: https://github.com/projectacrn/acrn-hypervisor