On Tue, Feb 25, 2014 at 10:00:08AM +0000, Marc Zyngier wrote: > On 21/02/14 17:12, Christoffer Dall wrote: > > On Fri, Feb 21, 2014 at 11:46:56AM +0000, Marc Zyngier wrote: > >> Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added > >> support for CPU power-management, using a cpu_notifier to re-init > >> KVM on a CPU that entered CPU idle. > >> > >> The code assumed that a CPU entering idle would actually be powered > >> off, loosing its state entierely, and would then need to be > >> reinitialized. It turns out that this is not always the case, and > >> some HW performs CPU PM without actually killing the core. In this > >> case, we try to reinitialize KVM while it is still live. It ends up > >> badly, as reported by Andre Przywara (using a Calxeda Midway): > >> > >> [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760 > >> [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150 > >> [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0 > >> > >> The trick here is to detect if we've been through a full re-init or > >> not by looking at HVBAR (VBAR_EL2 on arm64). This involves > >> implementing the backend for __hyp_get_vectors in the main KVM HYP > >> code (rather small), and checking the return value against the > >> default one when the CPU notifier is called on CPU_PM_EXIT. > >> > >> Reported-by: Andre Przywara <osp@xxxxxxxxx> > >> Tested-by: Andre Przywara <osp@xxxxxxxxx> > >> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> > >> Cc: Rob Herring <rob.herring@xxxxxxxxxx> > >> Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > >> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > > > > Thanks! > > > > Looks good. > > Thanks. I'm thinking of pushing this to 3.14 as a fix. Any objection? > Nope, go for it. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
