Re: [PATCH kernel] powerpc/ioda: Use ibm,supported-tce-sizes for IOMMU page size mask

On Wed, 2018-05-02 at 16:12 +1000, Alexey Kardashevskiy wrote:

At the moment we assume that IODA2 and newer PHBs can always do
4K/64K/16M
IOMMU pages, however this is not the case for POWER9 and now skiboot
advertises the supported sizes via the device so we use that instead
of hard coding the mask.

This falls back to the default mask if no "ibm,supported-tce-sizes"
is provided. This removes 16MB from the defaults as it is not
supported
everywhere; the downside of this is that hugepages backed POWER8
guests
will fall back to 64K IOMMU pages until skiboot is updated.

Signed-off-by: Alexey Kardashevskiy <redacted>

Reviewed-by: Russell Currey <redacted>