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24c339202c
With drm_gpusvm_pages now self contained, make xe stop relying
on the drm_gpusvm_range pages and take responsibility for the page
lifecycle on the driver side.
Driver side (xe):
- Embed struct drm_gpusvm_pages in xe_svm_range and route all
xe accesses through it instead of range->base.pages.
- Initialise the embedded pages via drm_gpusvm_init_pages(), which
binds the owning &xe->drm up front, and take over the page
lifecycle: xe_svm_range_get_pages() calls drm_gpusvm_get_pages()
directly; the notifier event_end and xe_svm_range_free() paths
drive unmap/free on the embedded pages object.
- Convert the open-coded userptr pages init in xe_userptr_setup()
to the same drm_gpusvm_init_pages() helper.
- Switch xe_svm_range_pages_valid() to drm_gpusvm_pages_valid().
Framework side (drm_gpusvm):
- Add a small inline drm_gpusvm_init_pages() helper that records the
owning drm_device and initialises the per-pages state, giving
drivers a single hook to extend.
- Export drm_gpusvm_pages_valid() to let driver owned pages
can query mapping state without going through a range.
- Lifecycle change: drm_gpusvm_range_remove() no longer *triggers*
unmap/free of the embedded pages. The unmap/free logic itself stays
in the framework -- drm_gpusvm_free_pages() still performs the DMA
unmap (as an idempotent backstop) and frees the dma_addr array --
but the driver now owns *when* it runs, since the driver owns the
drm_gpusvm_pages object.
Side effect / contract: a driver that owns a drm_gpusvm_pages is now
responsible for its lifecycle: drm_gpusvm_init_pages() before first
use, and drm_gpusvm_free_pages() when the owner goes away. Xe does the
latter from its ops->range_free callback, which the framework invokes
once the range refcount drops to zero in drm_gpusvm_range_remove().
The timely DMA unmap for the IOMMU security model still happens in the
notifier invalidate path via drm_gpusvm_unmap_pages(); the unmap inside
drm_gpusvm_free_pages() is only a backstop for pages that were never
invalidated.
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Honglei Huang <honghuan@amd.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260630102127.392396-4-honghuan@amd.com
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