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

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Jan 16, 2009 at 12:25:14AM +0100, Jean-Yves Migeon wrote:
> 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.

Looks good, but did you try building XEN2 kernels ? I can't see the
xen_*mb() macros defined for xen2. I think defining them in
include/xen-public/xen.h should be enough.

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--