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. Alex _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
