[PATCH v3 3/5] drm/xe/bo: Add a bo remove callback

[Thomas Hellström]

On Tue, 2025-03-25 at 09:02 +0000, Matthew Auld wrote:
> On 24/03/2025 16:54, Thomas Hellström wrote:
> > On device unbind, migrate exported bos, including pagemap bos to
> > system. This allows importers to take proper action without
> > disruption. In particular, SVM clients on remote devices may
> > continue as if nothing happened, and can chose a different
> > placement.
> > 
> > The evict_flags() placement is chosen in such a way that bos that
> > aren't exported are purged.
> > 
> > For pinned bos, we unmap DMA, but their pages are not freed yet
> > since we can't be 100% sure they are not accessed.
> > 
> > All pinned external bos (not just the VRAM ones) are put on the
> > pinned.external list with this patch. But this only affects the
> > xe_bo_pci_dev_remove_pinned() function since !VRAM bos are
> > ignored by the suspend / resume functionality. As a follow-up we
> > could look at removing the suspend / resume iteration over
> > pinned external bos since we currently don't allow pinning
> > external bos in VRAM, and other external bos don't need any
> > special treatment at suspend / resume.
> > 
> > v2:
> > - Address review comments. (Matthew Auld).
> > v3:
> > - Don't introduce an external_evicted list (Matthew Auld)
> > - Add a discussion around suspend / resume behaviour to the
> >    commit message.
> > - Formatting fixes.
> > 
> > Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> 
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> 

Actually, there is a CI failure on LNL indicating that the pinned
kernel-bo dma-maps are actually needed at devm-managed release.

I'm in the process on testing this out on LNL, and if so I'll drop
these dma-unmaps and we'd continue down the route of ensuring that
these subsystems are indeed devm_ managed and not drmm_ managed.

Thanks,
Thomas