On Thu, 02 Aug 2018 08:56:20 +0200 Mike Galbraith <efa...@gmx.de> wrote:
> (arm-land adventures 1/3 take2 will have to wait, my cup runeth over) > > v4.14..v4.15 timer handling changes including calling kvm_timer_vcpu_load() I take it that this should be added to v4.16-rt and marked stable-rt? -- Steve > during kvm_preempt_ops.sched_in and taking vgic_dist.lpi_list_lock in the > timer interrupt handler required locks for which locking rules/context had > been changed be converted to raw_spinlock_t... > > Quoting virt/kvm/arm/vgic/vgic.c: > * Locking order is always: > * kvm->lock (mutex) > * its->cmd_lock (mutex) > * its->its_lock (mutex) > * vgic_cpu->ap_list_lock must be taken with IRQs disabled > * kvm->lpi_list_lock must be taken with IRQs disabled > * vgic_irq->irq_lock must be taken with IRQs disabled > * > * As the ap_list_lock might be taken from the timer interrupt handler, > * we have to disable IRQs before taking this lock and everything lower > * than it. > > ...and fixed the obvious bricking consequence of those changes for RT, > but left an RT specific kvm unit test timer failure in its wake. Handling > phys_timer in hard interrupt context as expected cures that failure. > > Pre: > PASS selftest-setup (2 tests) > PASS selftest-vectors-kernel (2 tests) > PASS selftest-vectors-user (2 tests) > PASS selftest-smp (65 tests) > PASS pci-test (1 tests) > PASS pmu (3 tests) > PASS gicv2-ipi (3 tests) > PASS gicv3-ipi (3 tests) > PASS gicv2-active (1 tests) > PASS gicv3-active (1 tests) > PASS psci (4 tests) > FAIL timer (8 tests, 1 unexpected failures) > > Post: > PASS selftest-setup (2 tests) > PASS selftest-vectors-kernel (2 tests) > PASS selftest-vectors-user (2 tests) > PASS selftest-smp (65 tests) > PASS pci-test (1 tests) > PASS pmu (3 tests) > PASS gicv2-ipi (3 tests) > PASS gicv3-ipi (3 tests) > PASS gicv2-active (1 tests) > PASS gicv3-active (1 tests) > PASS psci (4 tests) > PASS timer (8 tests) > > Signed-off-by: Mike Galbraith <efa...@gmx.de> > --- > virt/kvm/arm/arch_timer.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/virt/kvm/arm/arch_timer.c > +++ b/virt/kvm/arm/arch_timer.c > @@ -634,7 +634,7 @@ void kvm_timer_vcpu_init(struct kvm_vcpu > hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); > timer->bg_timer.function = kvm_bg_timer_expire; > > - hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); > + hrtimer_init(&timer->phys_timer, CLOCK_MONOTONIC, > HRTIMER_MODE_ABS_HARD); > timer->phys_timer.function = kvm_phys_timer_expire; > > vtimer->irq.irq = default_vtimer_irq.irq;
