Hi Simon, On Tue, 21 Feb 2023 16:28:36 +0000, "Veith, Simon" <sveith@xxxxxxxxx> wrote: > > Hello Marc, > > On Thu, 2023-02-16 at 14:21 +0000, Marc Zyngier wrote: > > This series aims at satisfying multiple goals: > > > > - allow a VMM to atomically restore a timer offset for a whole VM > > instead of updating the offset each time a vcpu get its counter > > written > > > > - allow a VMM to save/restore the physical timer context, something > > that we cannot do at the moment due to the lack of offsetting > > > > - provide a framework that is suitable for NV support, where we get > > both global and per timer, per vcpu offsetting > > Thank you so much for following up on my (admittedly very basic) patch > with your own proposal! No worries. There is nothing like "nerd sniping"... ;-) > > This has been moderately tested with nVHE, VHE and NV. I do not have > > access to CNTPOFF-aware HW, so the jury is still out on that one > > Same here about CNTPOFF -- I gave it a quick spin on Graviton2 and > Graviton3, and neither chip claims the ARM64_HAS_ECV_CNTPOFF capability > from your patch. Nah, G2/G3 are old stuff (v8.2 and v8.3+ respectively). You need at least a v8.6 system, something that is made of the best Unobtainium money can buy. M2 has ECV, but without CNTPOFF, which is just silly. > I am working on testing your series with our userspace and will report > back. Thanks a lot, that'd be super helpful. Please don't get too attached to the userspace interface though, as it is likely to change (Oliver has an interesting suggestion to simplify it, but I need to convince myself that it doesn't break migration of the physical timer). Thanks, M. -- Without deviation from the norm, progress is not possible.
