On Wed, Sep 23, 2015 at 01:24:00PM +0200, Thomas Huth wrote: > On 17/09/15 18:54, Alex Williamson wrote: > > On Thu, 2015-09-17 at 23:09 +1000, David Gibson wrote: > >> Because of the way non-VFIO guest IOMMU operations are KVM accelerated, not > >> all TCE tables (guest IOMMU contexts) can support VFIO devices. Currently, > >> this is decided at creation time. > >> > >> To support hotplug of VFIO devices, we need to allow a TCE table which > >> previously didn't allow VFIO devices to be switched so that it can. This > >> patch adds an spapr_tce_need_vfio() function to do this, by reallocating > >> the table in userspace if necessary. > >> > >> Currently this doesn't allow the KVM acceleration to be re-enabled if all > >> the VFIO devices are removed. That's an optimization for another time. > > > > > > Same comment as previous patch, spapr_tce_need_userspace_table() (or > > something) makes the code much more self documenting. > > May I also add the using the word "need" in a function name is could be > a little bit confusing here? It's maybe just me, but if I read > ..._need_...() I first think of a function that just checks something > and returns a boolean for yes or no, not of a function that changes > something. > Could you maybe use something like "..._change_to_..." instead?
Yeah, I never did much like that name, just couldn't think of a better
one.
Hmm.. how about spapr_tce_set_need_vfio(), taking a bool parameter. I
won't implement the reverse transition just yet, but that gives us an
obvious place to put it when/if we do.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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