Avi Kivity wrote: > On 02/24/2010 11:54 AM, Jan Kiszka wrote: >> Avi Kivity wrote: >> >>> On 02/24/2010 11:41 AM, Jan Kiszka wrote: >>> >>>> Thomas Gleixner wrote: >>>> >>>> >>>>> On Tue, 23 Feb 2010, Jan Kiszka wrote: >>>>> >>>>> >>>>> >>>>>> Thomas Gleixner wrote: >>>>>> >>>>>> >>>>>>> The i8254/i8259 locks need to be real spinlocks on preempt-rt. Convert >>>>>>> them to raw_spinlock. No change for !RT kernels. >>>>>>> >>>>>>> >>>>>> Doesn't fly for -rt anymore: pic_irq_update runs under this raw lock and >>>>>> calls kvm_vcpu_kick which tries to wake_up some thread -> scheduling >>>>>> while atomic. >>>>>> >>>>>> >>>>> Hmm, a wakeup itself is fine. Is that code waking a wake queue ? >>>>> >>>>> >>>> Yes, it's a wake queue. >>>> >>>> >>> So what's the core issue? Is the lock_t in the wait_queue a sleeping mutex? >>> >> Yep. >> > > I see. Won't we hit the same issue when we call pic functions from > atomic context during the guest entry sequence? > If there are such call paths, for sure. What concrete path(s) do you have in mind? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
