[libvirt] [PATCH] docs: Document hypervisor drivers that support certain timer models

Jim Fehlig jfehlig at suse.com
Wed Jun 26 21:09:41 UTC 2013


Paolo Bonzini wrote:
> Il 25/06/2013 17:26, Jim Fehlig ha scritto:
>   
>>>> -            being modified, and can be one of "platform", "hpet",
>>>> -            "kvmclock", "pit", "rtc", or "tsc".
>>>> +            being modified, and can be one of
>>>> +            "platform" (currently unsupported),
>>>>         
>
> Platform should be supported by Xen, though it's not implemented yet.
> My reading of the spec is that
>
> mode='delay' track='guest'       corresponds to timer_mode=0
> mode='delay' track='wall'        corresponds to timer_mode=1
> mode='catchup'                   corresponds to timer_mode=2
> mode='merge'                     corresponds to timer_mode=3
>   

By spec, do you mean xen/include/public/hvm/params.h in the xen
sources?  That is the only "spec" I can find.  If I'm reading the
comments in that header correctly, seems your mapping is correct with
s/mode/tickpolicy/.

>   
>>>> +            "hpet" (libxl, qemu), "kvmclock" (xen, libxl, qemu),
>>>>   
>>>>         
>> xen supports hpet too, but I don't think xen or libxl support kvmclock.
>>     
>
> Agreed.
>
>   
>>>> +            "pit" (qemu), "rtc" (qemu), or "tsc" (libxl).
>>>>   
>>>>         
>> xen and libxl support rtc too.
>>     
>
> They do not support it in <timer> though, do they?

Oh, right.  Neither of the drivers support it in <timer>, they simply
support setting rtc to localtime or utc, i.e. the offset attribute of
<clock>.

Regards,
Jim




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