[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] HVM Migration of domU on Qemu-upstream DM causes stuck system clock with ACPI



On 03/06/13 18:18, Alex Bligh wrote:
George,

--On 3 June 2013 18:12:47 +0100 George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:

Will this work with all guests? We (unfortunately) do not know whether
the
guest is Linux with or without PV, Windows with or without PV or what. I
/think/ this is going to give problems when the guest is not using
the PV timer (including Windows). Is that right?

I'd be happiest if it selected native_paravirt whenever the guest was
using the PV timer, but not otherwise. Happy to test patches for that.

I'm not sure the effect, but I suspect it probably won't work quite
right.  Might be worth a quick test.

We do want to fix this properly (which means, "just works w/o having to
use a work-around"); I'm trying to understand the exact nature of the
error now.

Sorry did you mean using native_paravirt on Linux guests with PV support
wouldn't work quite right, or using that on all guests wouldn't work quite
right, or that switching automatically if use of the PV timer was
detected wouldn't work quite right?

I mean that if you enable it for guests that aren't using a PV clocksource (e.g., Windows guests), I'm not sure what will happen. It might be fine, but you should probably test it. :-)

Switching TSC modes isn't the right thing to do -- the right thing is to figure out where the math is getting messed up and make it work properly no matter which mode you're in.

 -George




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.