RE: [PATCH] fix x2apic defect that Linux kernel doesn't mask 8259Ainterrupt during the time window between changing VT-d table base addressand initializing these VT-d entries(smpboot.c and apic.c )

From: Suresh Siddha
Date: Wed Oct 10 2012 - 20:00:27 EST

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In reply to: Zhang, Lin-Bao (Linux Kernel R&D): "RE: [PATCH] fix x2apic defect that Linux kernel doesn't mask 8259Ainterrupt during the time window between changing VT-d table base addressand initializing these VT-d entries(smpboot.c and apic.c )"
Next in thread: Zhang, Lin-Bao (Linux Kernel R&D): "RE: [PATCH] fix x2apic defect that Linux kernel doesn't mask 8259Ainterrupt during the time window between changing VT-d table base addressand initializing these VT-d entries(smpboot.c and apic.c )"
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On Wed, 2012-10-10 at 16:02 -0700, Zhang, Lin-Bao (Linux Kernel R&D)
wrote:
> > As I mentioned earlier, the current design already ensures that all the IO-APIC
> > RTE's are masked between the time we enable interrupt-remapping to the time
> > when the IO-APIC RTE's are configured correctly.
> >
> > So I looked at why you are seeing the problem with v2.6.32 but not with the
> > recent kernels. And I think I found out the reason.
>
> I want to know what masking IO-APIC means?

As the platform is configured to use virtual-wire B and the
corresponding IO-APIC RTE is masked, that interrupt will be dropped.

thanks,
suresh

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