[Xen-ia64-devel] [PATCH] Cleanup to irq.c

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

This patch is a big cleanup to irq.c, with only real
necessary interfaces kept now. The irq subsystem of
xen is very simple since most external devices are
controlled by dom0. Also especially there's no need
to keep CONFIG_XEN everywhere, since this file is
already out of sync of linux version for a long time.
Actually xen defines irq related structures differently
and it's worthy of creating a xen specific version here.

Another change of this patch is to remove ugly check
upon timer/ipi within irq handler. Instead now we'll
check IRQ_GUEST flag of irq_desc to decide whether
to deliver irq to guest. Now all vectors un-registered
are set with IRQ_GUEST enabled, which is identical to
current assumption. Later this flag should be set only
per guest's request. Then Xen_do_irq is not reuqired
as the result of this change.

Signed-off-by Kevin Tian <kevin.tian@xxxxxxxxx>

BTW, one confusing point here is serial_input_init() which
hard coded a vector (0x30), which happens to conflict with
eth0 vector on my tiger box. What's the purpose of this
registration? Actually the registration here is bogus which
never severs the purpose. Before my patch, previous logic
simply injects that vector (0x30) into guest since it's not
timer/ipi. Even xen wants to handle this vector, the
hw_interrupt_type assocated with this vector is no_irq_type
which is also bogus. Since it doesn't work as the code wants, 
I simply disabled the serial_input_init to avoid unnecessary
warnings like " Unexpected irq vector 0x30 on cpu 0".

If anyone has special requirement on this part, we can modify
it later to make it really working. :-)

Thanks,
Kevin

Attachment: cleanup_irq.patch
Description: cleanup_irq.patch

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