[Xen-devel] [PATCH][FIX] Possible fix for spurious interrupts

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

Here is a patch that appears to fix the spurious interrupt problems for 
me. This is inspired by Jan's observation that the IO-APIC mask/unmask 
that we do for ISR processing seems to cause corruption of other 
routing entries. So the fix here is to do the same as native Linux -- 
do not mask/unmask, but instead send EOI after doing ISR processing.
To confirm this really was the problem I modified native Linux to do 
the same as Xen currently does (mask before ISR processing; unmask 
after). I then got lots of spurious USB interrupts even on native 
Linux! :-(
Please test... I'll put it in xen-unstable tomorrow if there are no 
complaints and it will be a strong candidate for the next 3.0.2 release 
too.
 -- Keir

Attachment: ioapic.patch
Description: Binary data

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