[PATCH 2 of 3] [KVM] Add DCR access information to struct kvm_run

Hollis Blanchard hollisb at us.ibm.com
Tue Apr 8 13:25:32 EST 2008


On Monday 07 April 2008 20:11:28 David Gibson wrote:
> On Mon, Apr 07, 2008 at 03:53:33PM -0500, Hollis Blanchard wrote:
> > 1 file changed, 7 insertions(+)
> > include/linux/kvm.h |    7 +++++++
> >
> >
> > Device Control Registers are essentially another address space found on
> > PowerPC 4xx processors, analogous to PIO on x86. DCRs are always 32 bits,
> > and are identified by a 32-bit number.
>
> Well... 10-bit, actually.

The mtdcrux description in the ppc440x6 user manual says the following:

	Let the contents of register RA denote a Device Control Register.
	The contents of GPR[RS] are placed into the designated Device Control 
Register.

I take that to mean that we must worry about 32 bits worth of DCR numbers. 
Perhaps I should say "no more than" rather than "always".

-- 
Hollis Blanchard
IBM Linux Technology Center



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