Re: [patch] x86: kvm: Convert i8254/i8259 locks to raw_spinlocks

[Jan Kiszka <jan.kiszka@xxxxxxxxxxx>]

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.

This used to work up to 956f97cf. -rt for 2.6.31 is not yet affected,
but 2.6.33 should be broken (haven't checked, using kvm-kmod over 2.6.31
ATM). I can provide a patch that restores the deferred kicking if it's
acceptable for upstream.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html