drm/xe: have xe_svm_range embed one drm_gpusvm_pages

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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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This commit is contained in:

Honglei Huang 2026-06-30 18:21:25 +08:00 • committed by Matthew Brost

parent 1d0c4c15c2

commit 24c339202c

6 changed files with 74 additions and 23 deletions

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16

drivers/gpu/drm/drm_gpusvm.c

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2

drivers/gpu/drm/xe/xe_pt.c

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42

drivers/gpu/drm/xe/xe_svm.c

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12

drivers/gpu/drm/xe/xe_svm.h

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5

drivers/gpu/drm/xe/xe_userptr.c

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20

include/drm/drm_gpusvm.h

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