MI Xen drivers (was: Re: [patch] x86_*fence replaced by membar_ops(3))

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Manuel Bouyer wrote:
> On Thu, Jan 15, 2009 at 03:13:59PM +0100, Jean-Yves Migeon wrote:
> > > > What should I do? Drop it for the x86 generic bus code, and keep it for 
> > > > the Xen drivers?
> > > No, membar_ops won't work for bus_dma/bus_space either. membar_ops are 
> > > patched
> > > to be NOP on UP kernels, still they're needed for interfaces with 
> > > devices.
> > Hmm, I was not really clear on that one: I just meant to keep the 
> > membar_ops(3) routines for the xennet, xbd and xencons drivers: since we 
> > do not patch the LOCK prefix for UP Xen domains, they are close to the 
> > x86_*fence() ones.
>
> Actually yes; but we'll probably want to use x86_patch() in the future.

Second attempt, this time for Xen code only, using xen_*mb() macros (the 
same than those used in the different ring-I/O APIs from Xen).

http://www.netbsd.org/~jym/MI-Xen-drivers.diff

Next step is to abstract the p2m routines. As most of them already use 
pmap(9), work is almost done (thanks Manuel). A few exceptions like 
direct use of the xpmap_phys_to_machine_mapping[] remain, I will have a 
look at how P2M is handled on other archs (ia64 comes to mind).

Please review.

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost