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Re: [Xen-devel] [PATCH 0 of 6] [RFC] Use wait queues for paging, v2



On Thu, Mar 15, Tim Deegan wrote:

> At 20:56 +0100 on 29 Feb (1330548983), Olaf Hering wrote:
> > On Wed, Feb 29, Olaf Hering wrote:
> > 
> > > This is the domain_lock() in xenmem_add_to_physmap_once(). 
> > > 
> > > Is get_gfn_untyped() correct, or would get_gfn_query() work as well in
> > > this context?
> 
> get_gfn_untyped() is correct.  I'm not sure that we really need to take
> the domain lock while we're doing it, though.  It might be that the new
> gfn locks will be enough to serialize these updates.
> 
> > Another case is emulate_privileged_op(), in "Write CR3" case
> > get_gfn_untyped() is called with domain_lock().
> 
> I think that should be OK as it only happens for PV guests. 

I think its just me not knowing these things, but would it make sense to
add comments to XX_lock users describing what they protect (or used to
protect since comments can stale over time)?

Olaf

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