[PATCH 5/5] drm/amdgpu: replace iova debugfs file with iomem

[Christian König]

Am 09.02.2018 um 15:51 schrieb Tom St Denis:
> On 09/02/18 09:12 AM, Christian König wrote:
>> No, there is simply no need to initialize the system domain. What are 
>> the values of p->mapping and adev->mman.bdev.dev_mapping when they 
>> don't match? Maybe we are allocating memory before initializing 
>> adev->mman.bdev.dev_mapping.
>
> In my test setup I'm running test 3 from libdrm (suite 1) with a pause 
> before the unmap/free call.  So the IB should still be mapped.  Indeed 
> the VM PTE decoding has the V bit set.
>
>> Or do you have more than one GPU in the system? E.g. APU+dGPU? Could 
>> it be that you read through the wrong device?
>
> I found the issue:
>
>     while (size) {
>         phys_addr_t addr = *pos & PAGE_MASK;
>         loff_t off = *pos & ~PAGE_MASK;
>         size_t bytes = PAGE_SIZE - off;
>
> "bytes" should be limited by the 'size' parameter passed in.  What is 
> happening instead is it's reading the entire PTB until it hits a V=0 
> page and then returns an error and in the process is doing "fun 
> things" to the user mode application (by copying more data than I 
> asked for).

Ah, obvious problem.

Do you want to fix it or should I take a look? You wanted to add write 
support as well anyway IIRC.

I've just pushed the first three patches from that series to 
amd-staging-drm-next.

Thanks for testing,
Christian.

>
>
> Tom