Re: [RFC PATCH v1] memory: tegra: Block DMA for clients HW on a faulty memory access

Mikko Perttunen
2018-08-05T00:12:02Z

One potential issue is with host1x clients where userspace processes can
submit jobs with invalid memory accesses (addresses not mapped to
IOMMU). If when such a failure happens, we disable the DMA for the whole
host1x client, unrelated userspace processes may see failures even
though there is no problem with their jobs.

Mikko

On 08/04/2018 02:53 PM, Dmitry Osipenko wrote:
> On Tuesday, 8 May 2018 19:58:41 MSK Dmitry Osipenko wrote:
>> Currently Memory Controller informs about erroneous memory accesses done
>> by memory clients and that's it. Let's make it to block whole HW unit
>> that corresponds to the misbehaving memory client in order to try to avoid
>> memory corruptions and to stop deliberate attempts of manipulation by a
>> misbehaving client.
>
> Guys, any comments? That is a kinda useful feature, in worst case only some of
> memory could get corrupted instead of trashing the whole memory. In my
> experience with T20/30, the interrupt handling latency is low and blocking
> happens immediately after the first page fault.
>
>
>