[vbox-dev] ICH9 MSI handling

Ananth Pallapothu apallapothu at gmail.com
Mon Dec 21 04:15:46 GMT 2015

Hello Developers,

      I am experimenting on ICH9 with a pluggable device. Reason for using
ICH9 is MSI support.
Following through AHCI, HPET device I see that code is aligned for specific
mode of MSI configuration, "Per-Vector Masking Capable".

      MsiNotify function reads Mask Bits, Pending Bits without
conditionally checking whether device is Per-Vector Masking Capable. So, by
default code thinks offset 0xC reg as mask data where infact it is MSI data
with Interrupt Vector ID incase of masking disabled. iVector value seems to
be confusing too.

     My particular device needs to be configured for 64 bit MSI address
capable and Mask disabled, so, MSI_MSG_CNTL @ MSI capability offset 0x02 =

    Can someone please suggest, recommend changes to handle this mode of
MSI operation ?

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