On Thu, Oct 18, 2012 at 10:09 AM, Alexander Graf <agraf@xxxxxxx> wrote: > > On 18.10.2012, at 16:05, Marc Zyngier wrote: > >> On 18/10/12 14:51, Christoffer Dall wrote: >>> On Thu, Oct 18, 2012 at 7:00 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>>> On 17/10/12 21:09, Christoffer Dall wrote: >>>>> On Wed, Oct 17, 2012 at 1:22 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>>>>> On 17/10/12 17:53, Christoffer Dall wrote: >>>>>>> On Wed, Oct 17, 2012 at 12:09 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>>>>>>> On 17/10/12 16:50, Christoffer Dall wrote: >>>>>>>>>>>> ARM: KVM: move MMIO handling to its own files >>>>>>>>>>> >>>>>>>>>>> this one I'll look at later today. >>>>>>>>>> >>>>>>>>>> OK. Let me know what you think. I have a couple of other patches on the >>>>>>>>>> same theme. >>>>>>>>>> >>>>>>>>> >>>>>>>>> I will. Since the mmio handling is controversial, it's good that we >>>>>>>>> split that up. >>>>>>>>> >>>>>>>>> Unless the other patches are *necessary* for an upstream merge, I >>>>>>>>> think we should announce a code freeze and target an upstream merge >>>>>>>>> asap for everyone's benefit. >>>>>>>> >>>>>>>> Depending what you can necessary. A number of patches I've queued are >>>>>>>> related to moving accesses to HSR and friends into inline functions, >>>>>>>> making the code more readable - again, this could help the reviewers. >>>>>>>> They are mostly one-liners. >>>>>>>> >>>>>>> >>>>>>> necessary as in bugfixes or API stabilization. >>>>>>> >>>>>>> My whole point is that we can keep improving forever, but the more >>>>>>> cosmetics we change the more changes need to be reviewed. >>>>>> >>>>>> I agree on the stabilization. But my point here is not to introduce new >>>>>> features. Just to make the core mode easily reviewed. One of the >>>>>> complains I've heard so far is that the code is hard to read. Which is >>>>>> not surprising given that there's a lot of it, and that the problems it >>>>>> tackles are not simple. >>>>>> >>>>>> I'll post these patches as an RFC, and you're free to take them or not. >>>>>> >>>>> >>>>> ok, thanks, I'll have a look. >>>> >>>> Incoming. >>>> >>>>>>>>> It seems to me that we have a bug on restart to fix and >>>>>>>> >>>>>>>> Care to elaborate on this one? >>>>>>>> >>>>>>> >>>>>>> just fire up a guest and execute "reboot" in there and see the guest >>>>>>> kernel crash when it comes back up. If you can't reproduce, we should >>>>>>> talk more :) >>>>>> >>>>>> Interesting. It looks like the guest is taking a timer interrupt before >>>>>> being ready to handle it... Probably because the timer has been disabled >>>>>> while something is still pending. Investigating. >>>>>> >>>>> >>>>> yeah, but a reset should mask interrupts, right? so I'm not sure, >>>>> anyway cool if you have cycles to look into it. >>>> >>>> Reset? Which reset? We do not have a mechanism to propagate QEMU's reset >>>> into the VM. I think that is part of the problem, but that would be >>>> papering over a real bug hiding somewhere. Either in the vgic code or in >>>> the timer. >>>> >>> >>> I actually assumed that a reboot would generate a virtual reset to the >>> cpu, but I haven't looked into this at all. What exactly happens in >>> the guest kernel side when you call reboot? >> >> You hit some special VE device that causes the VCPUs to be reset (Peter, >> can you be more specific than I am?), but we don't signal anything to >> the VM itself - hence the guest restarting with timers ticking and GIC >> in some arbitrary state (interrupts being queued into the list >> registers, for example...). > > If you ever want to do live migration, you need to be able to get/set the state of your GIC from user space anyways. So what would usually happen is that on reset, QEMU would just set the state to a known good reset state. > hmm, Marc, how would we expose the GIC state? That's more than just the list registers because we can have things queued on the kernel side as well right? oh no... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
