User space may create the PIT and forgets about setting up the irqchips.
In that case, firing PIT IRQs will crash the host:
BUG: unable to handle kernel NULL pointer dereference at
0000000000000128
IP: [<
ffffffffa10f6280>] kvm_set_irq+0x30/0x170 [kvm]
...
Call Trace:
[<
ffffffffa11228c1>] pit_do_work+0x51/0xd0 [kvm]
[<
ffffffff81071431>] process_one_work+0x111/0x4d0
[<
ffffffff81071bb2>] worker_thread+0x152/0x340
[<
ffffffff81075c8e>] kthread+0x7e/0x90
[<
ffffffff815a4474>] kernel_thread_helper+0x4/0x10
Prevent this by checking the irqchip mode before starting a timer. We
can't deny creating the PIT if the irqchips aren't set up yet as
current user land expects this order to work.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
return HRTIMER_NORESTART;
}
return HRTIMER_NORESTART;
}
-static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
+static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
+ struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
struct kvm_timer *pt = &ps->pit_timer;
s64 interval;
struct kvm_timer *pt = &ps->pit_timer;
s64 interval;
+ if (!irqchip_in_kernel(kvm))
+ return;
+
interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
pr_debug("create pit timer, interval is %llu nsec\n", interval);
interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
pr_debug("create pit timer, interval is %llu nsec\n", interval);
/* FIXME: enhance mode 4 precision */
case 4:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
/* FIXME: enhance mode 4 precision */
case 4:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
- create_pit_timer(ps, val, 0);
+ create_pit_timer(kvm, val, 0);
}
break;
case 2:
case 3:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
}
break;
case 2:
case 3:
if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
- create_pit_timer(ps, val, 1);
+ create_pit_timer(kvm, val, 1);