Re: VMI Interface Proposal Documentation for I386, Part 5

[Zwane Mwaikambo <zwane@arm.linux.org.uk>]

On Mon, 13 Mar 2006, Zachary Amsden wrote:

>   PROCESSOR STATE CALLS
> 
>    This set of calls controls the online status of the processor.  It
>    include interrupt control, reboot, halt, and shutdown functionality.
>    Future expansions may include deep sleep and hotplug CPU capabilities.
> 
>    VMI_DisableInterrupts
> 
>       VMICALL void VMI_DisableInterrupts(void);
> 
>       Disable maskable interrupts on the processor.
> 
>       Inputs:      None
>       Outputs:     None
>       Clobbers:    Flags only
>       Segments:    As this is both performance critical and likely to
>          be called from low level interrupt code, this call does not
>          require flat DS/ES segments, but uses the stack segment for
>          data access.  Therefore only CS/SS must be well defined.
> 
>    VMI_EnableInterrupts
> 
>       VMICALL void VMI_EnableInterrupts(void);
> 
>       Enable maskable interrupts on the processor.  Note that the
>       current implementation always will deliver any pending interrupts
>       on a call which enables interrupts, for compatibility with kernel
>       code which expects this behavior.  Whether this should be required
>       is open for debate.

Mind if i push this debate slightly forward? If we were to move the 
dispatch of pending interrupts elsewhere, where would that be? In 
particular, for a device which won't issue any more interrupts until it's 
previous interrupt is serviced. Perhaps injection at arbitrary points 
during runtime when interrupts are enabled?

	Zwane

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