Re: [Qemu-devel] [PATCH] re-set rtc date on reset handler

[Glauber Costa <glommer@gmail.com>]

On Tue, Sep 1, 2009 at 1:56 PM, Blue Swirl<blauwirbel@gmail.com> wrote:
> On Tue, Sep 1, 2009 at 7:22 PM, Glauber Costa<glommer@redhat.com> wrote:
>> guests without a stable timesource such as kvm-clock will grab the wallclock
>> from our rtc chip. However, we only sync the date when we first launch qemu.
>> If a guest goes through a series of reboot cycles, it will slowly see time
>> getting far behind the host.
>>
>> The proposal of this patch is to set the date to host clock again in the reset
>> handler. With this patch, I see a Fedora guest keeping its clock in sync upon
>> an ulimited number of reboots.
>
> A different approach is used in m48t59.c: the guest clock is generated
> directly from host clock without any timers and only a fixed offset
You mean at every ioport read? I actually thought about that, but was
too lazy...


-- 
Glauber  Costa.
"Free as in Freedom"
http://glommer.net

"The less confident you are, the more serious you have to act."