drm/xe: NULL binding implementation

Add uAPI and implementation for NULL bindings. A NULL binding is defined
as writes dropped and read zero. A single bit in the uAPI has been added
which results in a single bit in the PTEs being set.

NULL bindings are intendedd to be used to implement VK sparse bindings,
in particular residencyNonResidentStrict property.

v2: Fix BUG_ON shown in VK testing, fix check patch warning, fix
xe_pt_scan_64K, update __gen8_pte_encode to understand NULL bindings,
remove else if vma_addr

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Suggested-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index bb2996856841..5edb7771629c 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -115,11 +115,21 @@ static inline void xe_vm_reactivate_rebind(struct xe_vm *vm)
 	}
 }
 
-static inline bool xe_vma_is_userptr(struct xe_vma *vma)
+static inline bool xe_vma_is_null(struct xe_vma *vma)
+{
+	return vma->pte_flags & XE_PTE_FLAG_NULL;
+}
+
+static inline bool xe_vma_has_no_bo(struct xe_vma *vma)
 {
 	return !vma->bo;
 }
 
+static inline bool xe_vma_is_userptr(struct xe_vma *vma)
+{
+	return xe_vma_has_no_bo(vma) && !xe_vma_is_null(vma);
+}
+
 int xe_vma_userptr_pin_pages(struct xe_vma *vma);
 
 int xe_vma_userptr_check_repin(struct xe_vma *vma);