Re: [PATCH 0/6] MSI portability cleanups

From: Segher Boessenkool
Date: Tue Jan 30 2007 - 14:33:25 EST


I just got an answer from the hypervisor architects. It turns out
that the hardware _does_ prevent the device from sending MSI messages
to another partition. The OS _can_ write whatever it likes to the MSI
address and data registers. It can potentially lose interrupts (or, I
expect, get the device isolated by EEH) but it can't disrupt another
partition.

The OS however has to write the values the HV wants to
the device, or things won't work -- so the HV can just
as well do it itself. Also, pulling all the work into
the HV makes for a cleaner, more generic design (who
knows what hardware will show up within the next few
years, the HV interface had better be prepared).


Segher

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