[Qemu-devel] Re: [PATCH v5 00/14] pcie port switch emulators

[Isaku Yamahata]

On Wed, Oct 20, 2010 at 12:40:49AM +0200, Michael S. Tsirkin wrote:

> I think I suggested once a good way to implement this:
> 
> - always make the bits w1c
> - after config write:
>   if MHR is enabled, and you see that error log is not empty and that bit is 
> 0,
>   this means that someone has written 1b.
>   so pop the first error from the log, and set bit to 1 if it's not empty.
> 
> This way we only touch w1c mask on setup, no tricky range checks.
> Anything wrong with this approach?

Basically okay. 
Without the range checks, we need to restore the old value to the register
if 1b isn't written to the bit of the first error.
Probably you prefer restoring it mostly always than the range check.
-- 
yamahata