On 2021-04-07 3:34 p.m., Felix Kuehling wrote:
On 2021-04-07 7:25 a.m., Christian König wrote:
+ /*
+ * Don't verify access for KFD BOs. They don't have a GEM
+ * object associated with them.
+ */
+ if (bo->kfd_bo)
+ goto out;
Who does the access verification now?
This is somewhat confusing.
I took this check as-is, including the comment, from amdgpu's
verify_access function. The verify_access function was called by
ttm_bo_mmap. It returned 0 and ttm_bo_mmap did the mapping.
This is probably a left-over from when we mapped BOs using /dev/kfd. We
changed this to use /dev/dri/renderD* a long time ago to fix CPU
mapping
invalidations on memory evictions. I think we can let GEM do the access
check.
Ok, good to know.
Thomas can you remove the extra handling in a separate prerequisite
patch?
If anybody then bisects to this patch we at least know what to do to
get it working again.
FWIW, I ran KFDTest test with this shortcut removed on current
amd-staging-drm-next + my HMM patch series, and it didn't seem to
cause any issues.
Wait, I celebrated too soon. I was running the wrong kernel. I do see
some failures where access is being denied. I need to do more debugging
to figure out what's causing that.
Regards,
Felix
Regards,
Felix
Regards,
Christian.
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