On Tue, May 24, 2022 at 10:25:53AM -0300, Jason Gunthorpe wrote:
> On Mon, May 23, 2022 at 04:02:22PM +1000, Alexey Kardashevskiy wrote:
> 
> > Which means the guest RAM does not need to be all mapped in that base IOAS
> > suggested down this thread as that would mean all memory is pinned and
> > powervm won't be able to swap it out (yeah, it can do such thing now!). Not
> > sure if we really want to support this or stick to a simpler design.
> 
> Huh? How can it swap? Calling GUP is not optional. Either you call GUP
> at the start and there is no swap, or you call GUP for each vIOMMU
> hypercall.
> 
> Since everyone says PPC doesn't call GUP during the hypercall - how is
> it working?

The current implementation does GUP during the pre-reserve.  I think
Alexey's talking about a new PowerVM (IBM hypervisor) feature; I don't
know how that works.

-- 
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