[PATCH] iommu/arm-smmu-v3: avoid over allocating for l2 stream tables

Hi Nate,

On Mon, Dec 19, 2016 at 03:26:40PM -0500, Nate Watterson wrote:

Currently, all l2 stream tables are being allocated with space for
(1<<split) stes without regard to the number of sid bits the smmu
physically supports. To avoid allocating memory for inaccessible
stes, this patch limits the span of an l2 table to be no larger
than the sid size of the smmu to which it belongs.

Signed-off-by: Nate Watterson <redacted>
---
 drivers/iommu/arm-smmu-v3.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

I can't help but think you'd be better off using a linear stream table
in this scenario. If we hack the feature check for
ARM_SMMU_FEAT_2_LVL_STRTAB so that it doesn't report support for 2 level
tables if the number of sids is less than that covered by a single l2
entry, would that solve your problem?

Will