[SeaBIOS] [PATCH] tsc: use kvmclock for calibration

[Avi Kivity]

On 08/09/2012 05:18 PM, Gerd Hoffmann wrote:
>   Hi,
> 
>>> So what do you suggest?  The options I see are:
>>>
>>>   (1) Use this patch (with alignment issue fixed of course).
>>>   (2) Do a full kvmclock implementation.  Feels a bit like overkill.
>>>   (3) SeaBIOS can fallback to the PIT for timing on machines which
>>>       have no TSC.  We could do that too in case we detect kvm ...
>> 
>> What sort of timeouts are these?  If seconds, maybe the rtc would be best.
> 
> All sorts of timeouts, from a few miliseconds to seconds.
> 
> The problematic ones are the longer timeouts, which wait for I/O stuff
> like disk reads complete.  The stuff with smaller timeouts (like waiting
> for AHCI link become ready) tend to finish instantly in kvm.

That's not guaranteed.  The AHCI adapter might be real hardware.  Or the
emulation may change.

What's wrong with having a full kvmclock implementation?  Instead of
issuing rdtsc call a function pointer.

-- 
error compiling committee.c: too many arguments to function