On Friday, 19.06.2015 at 18:07, Anil Madhavapeddy wrote: > On 19 Jun 2015, at 17:50, Justin Cormack <[email protected]> wrote: > > > > On 19 June 2015 at 17:42, Martin Lucina <[email protected]> wrote: > >> Also note that I have no idea what the stability of TSC is under KVM and > >> the current code makes no attempt to figure out if TSC is invariant, > >> constant, or anything else. So option 3) would also be a safe(r) bet in > >> that the PIT should "just work". > > > > KVM has a PV clock, see summary of how it works here > > https://rwmj.wordpress.com/tag/kvmclock/ > > > > Because clocks under virtualization are problematic, using this is > > probably the best solution longer term. > > On Xen HVM, you can still use the PV hypercall to map the shared_info > page and get the PV clock from there. Does all of that "just work" > from the NetBSD Xen PCI bridge device driver and Rump/Xen?
Rumprun on xen is currently PV only, and uses the PV clock from shared_info, so yes, it all "just works" there. Martin
