Jamie Lokier wrote:
Anthony Liguori wrote:
Besides the interface thing, I'm also interesting in comments on the
other core idea, the selectable RTC base clock. Do we want this knob? Do
we want host_clock unconditionally? Or should the other RTC that
currently use the host time already also gain vm_clock support over the
time?
Hard to say. Doesn't the rtc keep track of wallclock time even on power
off? I think using host_clock unconditionally does actually make sense.
Sometimes it's useful to offset the emulated clock for one reason or
another, hence the -startdate options. But having it run at the
correct speed is usually useful :-)
Indeed.
Also, sometimes (due to licenses with wallclock limits) it's useful
for a guest to not see much time pass when the guest is powered off,
although it still needs to be positive.
I'm not sure if this is a common use case. And it currently only seems
to be support by very few RTCs, the MC146818 being the most prominent one.
I'm now a fan of converting the latter to the common scheme of using the
host's system time (here via host_clock) and watch out for the need of
adding -rtc clock=vm.