tree b0b2bcefa0a062bb4380fba162eb36876f0e331e
parent 2e60baca235b05d4026207e31b6fc385c0c1c122
author Alexey Kardashevskiy <aik@ozlabs.ru> 1489711709 +0000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1490183018 +0100

vfio/spapr: Postpone default window creation

[ Upstream commit d9c728949ddc9de5734bf3b12ea906ca8a77f2a0 ]

We are going to allow the userspace to configure container in
one memory context and pass container fd to another so
we are postponing memory allocations accounted against
the locked memory limit. One of previous patches took care of
it_userspace.

At the moment we create the default DMA window when the first group is
attached to a container; this is done for the userspace which is not
DDW-aware but familiar with the SPAPR TCE IOMMU v2 in the part of memory
pre-registration - such client expects the default DMA window to exist.

This postpones the default DMA window allocation till one of
the folliwing happens:
1. first map/unmap request arrives;
2. new window is requested;
This adds noop for the case when the userspace requested removal
of the default window which has not been created yet.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>