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Extend the DRM_XE_MADVISE ioctl to support purgeable buffer object management by adding DRM_XE_VMA_ATTR_PURGEABLE_STATE attribute type. This allows userspace applications to provide memory usage hints to the kernel for better memory management under pressure: - WILLNEED: Buffer is needed and should not be purged. If the BO was previously purged, retained field returns 0 indicating backing store was lost (once purged, always purged semantics matching i915). - DONTNEED: Buffer is not currently needed and may be purged by the kernel under memory pressure to free resources. Only applies to non-shared BOs. To prevent undefined behavior, the following operations are blocked while a BO is in DONTNEED state: - New mmap() operations return -EBUSY - VM_BIND operations return -EBUSY - New dma-buf exports return -EBUSY - CPU page faults return SIGBUS - GPU page faults fail with -EACCES This ensures applications cannot use a BO while marked as DONTNEED, preventing erratic behavior when the kernel purges the backing store. The implementation includes a 'retained' output field (matching i915's drm_i915_gem_madvise.retained) that indicates whether the BO's backing store still exists (1) or has been purged (0). Added DRM_XE_QUERY_CONFIG_FLAG_HAS_PURGING_SUPPORT flag to allow userspace to detect kernel support for purgeable buffer objects before attempting to use the feature. Cc: Matthew Brost <matthew.brost@intel.com> Acked-by: José Roberto de Souza <jose.souza@intel.com> Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com> Signed-off-by: Arvind Yadav <arvind.yadav@intel.com> Signed-off-by: Matthew Brost <matthew.brost@intel.com> Link: https://patch.msgid.link/20260326130843.3545241-2-arvind.yadav@intel.com