Re: [PATCH] drm/ttm: Don't inherit GEM object VMAs in child process

Am 2022-01-05 um 11:16 a.m. schrieb Felix Kuehling:

...

I was already wondering which mmaps through the KFD node we have left which cause problems here.

We still use the KFD FD for mapping doorbells and HDP flushing. These are both SG BOs, so they cannot be CPU-mapped through render nodes. The KFD FD is also used for mapping signal pages and CWSR trap handlers on old APUs.

Those VMAs aren't causing the problem. They still map successfully on restore.

Small correction: KFD already sets the VM_DONTCOPY flag for all KFD FD mappings.

The patch under discussion here does the same for DRM FD mappings (at least for KFD BOs).

Regards,   Felix