linux/arch/x86/kernel/apic
Suresh Siddha 0280f7c416 x86, x2apic: cleanup the IO-APIC level migration with interrupt-remapping
Impact: simplification

In the current code, for level triggered migration, we need to modify the
io-apic RTE with the update vector information, along with modifying interrupt
remapping table entry(IRTE) with vector and destination. This is to ensure that
remote IRR bit inthe IOAPIC RTE gets cleared when the cpu does EOI.

With this patch, for level triggered, we eliminate the io-apic RTE modification
(with the updated vector information), by using a virtual vector (io-apic pin
number).  Real vector that is used for interrupting cpu will be coming from
the interrupt-remapping table entry. Trigger mode in the IRTE will always be
edge, and the actual level or edge trigger will be setup in the IO-APIC RTE.
So a level triggered interrupt will appear as an edge to the local apic
cpu but still as level to the IO-APIC.

With this change, level irq migration can be done by simply modifying
the interrupt-remapping table entry with out changing the io-apic RTE.
And as the interrupt appears as edge at the cpu, in addition to do the
local apic EOI, we need to do IO-APIC directed EOI to clear the remote
IRR bit in  the IO-APIC RTE.

This simplies the irq migration in the presence of interrupt-remapping.

Idea-by: Rajesh Sankaran <rajesh.sankaran@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-03-17 15:44:27 -07:00
..
apic_flat_64.c x86: apic: simplify secondary CPU wakeup methods 2009-02-26 13:58:26 +01:00
apic.c x86, x2apic: fix clear_local_APIC() in the presence of x2apic 2009-03-17 15:43:51 -07:00
bigsmp_32.c x86_32: apic/bigsmp_32, de-inline functions 2009-03-02 11:20:32 +01:00
es7000_32.c x86_32: apic/es7000_32, fix section mismatch 2009-03-02 12:00:24 +01:00
io_apic.c x86, x2apic: cleanup the IO-APIC level migration with interrupt-remapping 2009-03-17 15:44:27 -07:00
ipi.c
Makefile x86, apic: separate 32-bit setup functionality out of apic_32.c 2009-02-17 23:12:48 +01:00
nmi.c
numaq_32.c x86_32: apic/numaq_32, fix section mismatch 2009-03-02 12:00:25 +01:00
probe_32.c x86: apic: simplify secondary CPU wakeup methods 2009-02-26 13:58:26 +01:00
probe_64.c x86, x2apic: enable fault handling for intr-remapping 2009-03-17 15:38:59 -07:00
summit_32.c x86_32: apic/summit_32, fix section mismatch 2009-03-02 12:00:25 +01:00
x2apic_cluster.c x86: apic: simplify secondary CPU wakeup methods 2009-02-26 13:58:26 +01:00
x2apic_phys.c x86: apic: simplify secondary CPU wakeup methods 2009-02-26 13:58:26 +01:00
x2apic_uv_x.c x86: apic: simplify secondary CPU wakeup methods, fix 2009-02-26 14:11:06 +01:00