[RFC PATCH 2/7] iommu/arm-smmu-v3: Do resource size checks based on smmu option PAGE0_REGS_ONLY

Sunil Kovvuri
2017-04-11T16:39:39Z

On Tue, Apr 11, 2017 at 9:13 PM, Robin Murphy <robin.murphy@arm.com> wrote:
> On 11/04/17 15:42, linucherian at gmail.com wrote:
>> From: Linu Cherian <linu.cherian@cavium.com>
>>
>> With implementations supporting only page 0 of register space,
>> resource size can be 64k as well and hence perform size checks
>> based on smmu option PAGE0_REGS_ONLY.
>
> What harm comes of mapping page 1 if we don't access it?
>
> Robin.
>

There are multiple SMMUs on the silicon and CSRs of each SMMU are
64K apart. Hence can't map page-1 even though it's not accessed.

Thanks,
Sunil.