[Qemu-devel] Re: [PATCH 16/23] pci: pcie host and mmcfg support.

[Michael S. Tsirkin]

On Wed, Oct 07, 2009 at 11:25:46AM +0900, Isaku Yamahata wrote:
> The above code doesn't work.
> Some bits in configuration space must be virtualized, it means that
> virtualized value must be stored in memory.
> Limiting 256 bytes would just make unnecessary complication.
> We have to add many hooks like if (offset > 256) call_express_code()
> and the express code would be almost same as pci one.
> We've already had direct attached code. The difference for pci express 
> direct attach from pci direct attach is just that the code receives offset
> in configuration space which might be greater than 255.

Okay. What I mainly disliked is the complex update routines.  But I
found a way to get rid of them without limiting ourselves to 256 bytes
size: in fact, we only need to save the first 64 bytes for default
config callback, whatever the full config space size is.

Since this is a single cache line, it won't get any more efficient,
and we can use simple memcmp to check for bar changes etc.

Patch soon, please review and let me know.

-- 
MST