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[Qemu-devel] [PATCH 0/2 v2] Time resync support by qemu-ga


From: Lei Li
Subject: [Qemu-devel] [PATCH 0/2 v2] Time resync support by qemu-ga
Date: Mon, 28 Jan 2013 02:11:10 +0800

This patch series attempts to add time resync support
to qemu-ga by introducing qemu-ga commands guest-get-time
and guest-set-time.

Right now, when a guest is paused or migrated to a file
then loaded from that file, the guest OS has no idea that
there was a big gap in the time. Depending on how long the
gap was, NTP might not be able to resynchronize the guest.
So adding new guest-agent command that is called any time
a guest is resumed  and which tells the guest to update its
own wall clock time based on the information from the host
will make it easier for a guest to resynchronize without
waiting for NTP.

The previous RFC send for discussion and suggestion as link
here:

http://article.gmane.org/gmane.comp.emulators.qemu/186126

The interface for these commands like:

{ 'command': 'guest-get-time', 'returns': 'TimeInfo' }

{ 'command': 'guest-set-time',
  'data': { '*seconds': 'int', '*microseconds': 'int',
            '*utc-offset': 'int' } }

Notes:
I planed to send out this version with the implementition
of win32-specific commands, but got some environment issue
which I am working on. I will send it out very soon. To
avoid wasting of time, I'd like to send this out first with
the previous comments fixed to have more suggestions.

Suggestions and comments are welcome!

Changes since v1:
  - Squashed patches add support to get host time and add
    guest-get-time command into one.
  - Documents improvment based on the suggestions from
    Eric and Mike.
  - Change the name of 'HostTimeInfo' to 'TimeInfo'.
  - Better use-case and logic for 'guest-set-time'
    command suggested by Eric.
  - Error handel improvment from Luiz.

Lei Li (2):
  qga: add guest-get-time command
  qga: add guest-set-time command

 include/qapi/qmp/qerror.h |    3 +
 qga/commands-posix.c      |  106 +++++++++++++++++++++++++++++++++++++++++++++
 qga/qapi-schema.json      |   80 ++++++++++++++++++++++++++++++++++
 3 files changed, 189 insertions(+), 0 deletions(-)




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