Local APIC cannot deliver MSI to CPU (Fiasco.OC) ?

Chen Tian chen.tian at acm.org
Wed Aug 22 03:08:21 CEST 2012

I am trying to use MSI for my network card. After setting the MSI slot in
the PCI configuration block based on Intel manual, I can confirm the
interrupt is delivered to the processor's local APIC by looking at the IRR
content in kernel debugger. The bit in IRR that reflects the vector I
specified in MSI message is set to 1 by APIC. However, the interrupt
handler installed at that vector is never invoked. Does someone have any
idea on this? The priority does not seem to be the issue, because I checked
the TPR, which was 0x80 when I entered kernel debugger and decreased to 0
when I press 'g'. The error status register is also zero in the kernel
debugging mode, while there is a pending interrupt request as suggested by
IRR. But the cpu just can't get the interrupt. Any suggestions?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://os.inf.tu-dresden.de/pipermail/l4-hackers/attachments/20120821/89c71ed3/attachment.html>

More information about the l4-hackers mailing list