drm/pagemap, drm/xe: Support destination migration over interconnect

Support destination migration over interconnect when migrating from
device-private pages with the same dev_pagemap owner.

Since we now also collect device-private pages to migrate,
also abort migration if the range to migrate is already
fully populated with pages from the desired pagemap.

Finally return -EBUSY from drm_pagemap_populate_mm()
if the migration can't be completed without first migrating all
pages in the range to system. It is expected that the caller
will perform that before retrying the call to
drm_pagemap_populate_mm().

v3:
- Fix a bug where the p2p dma-address was never used.
- Postpone enabling destination interconnect migration,
  since xe devices require source interconnect migration to
  ensure the source L2 cache is flushed at migration time.
- Update the drm_pagemap_migrate_to_devmem() interface to
  pass migration details.
v4:
- Define XE_INTERCONNECT_P2P unconditionally (CI)
- Include a missing header (CI)
v5:
- Use page order increments where possible (Matt Brost).
- Fix a negated value of can_migrate_same_pagemap.
- Move removal of some dead code to a separate patch (Matt Brost).
- Remove an unnecessary zdd get() and put() (Matt Brost).

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-23-thomas.hellstrom@linux.intel.com

1 files changed, 18 insertions, 1 deletions

diff --git a/include/drm/drm_pagemap.h b/include/drm/drm_pagemap.h
index f73afece42ba..46e9c58f09e0 100644
--- a/include/drm/drm_pagemap.h
+++ b/include/drm/drm_pagemap.h
@@ -317,10 +317,27 @@ struct drm_pagemap_devmem {
 	struct dma_fence *pre_migrate_fence;
 };
 
+/**
+ * struct drm_pagemap_migrate_details - Details to govern migration.
+ * @timeslice_ms: The time requested for the migrated pagemap pages to
+ * be present in @mm before being allowed to be migrated back.
+ * @can_migrate_same_pagemap: Whether the copy function as indicated by
+ * the @source_peer_migrates flag, can migrate device pages within a
+ * single drm_pagemap.
+ * @source_peer_migrates: Whether on p2p migration, The source drm_pagemap
+ * should use the copy_to_ram() callback rather than the destination
+ * drm_pagemap should use the copy_to_devmem() callback.
+ */
+struct drm_pagemap_migrate_details {
+	unsigned long timeslice_ms;
+	u32 can_migrate_same_pagemap : 1;
+	u32 source_peer_migrates : 1;
+};
+
 int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation,
 				  struct mm_struct *mm,
 				  unsigned long start, unsigned long end,
-				  unsigned long timeslice_ms);
+				  const struct drm_pagemap_migrate_details *mdetails);
 
 int drm_pagemap_evict_to_ram(struct drm_pagemap_devmem *devmem_allocation);