[RFC v3 1/7] drm/xe/vm: Track CPU_AUTORESET state in xe_vma

[Arvind Yadav <arvind.yadav@intel.com>]

Track MADVISE_AUTORESET CPU-only state in struct xe_vma with a dedicated
cpu_autoreset_active bool.

Add XE_VMA_CPU_AUTORESET_ACTIVE as a pipeline-only bit to carry this
state through MAP/REMAP operations. Runtime state lives in
xe_vma.cpu_autoreset_active rather than vma->gpuva.flags.

The state is set at bind time and cleared on the first successful GPU
fault.

v2:
  - Move runtime state from gpuva.flags to xe_vma bool. (Matt)
  - Keep XE_VMA_CPU_AUTORESET_ACTIVE pipeline-only. (Matt)

v3:
  - Add kernel-doc and lockdep_assert_held to
    xe_vma_has_cpu_autoreset_active(). (Matt)

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
---
 drivers/gpu/drm/xe/xe_vm.h       | 14 ++++++++++++++
 drivers/gpu/drm/xe/xe_vm_types.h | 13 +++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index c5b900f38ded..0dd201cce968 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -181,6 +181,20 @@ static inline bool xe_vma_is_userptr(struct xe_vma *vma)
 		!xe_vma_is_cpu_addr_mirror(vma);
 }
 
+/**
+ * xe_vma_has_cpu_autoreset_active() - Check if VMA is still CPU-only
+ * @vma: VMA to check
+ *
+ * The caller must hold vm->lock (read or write).
+ *
+ * Return: true if CPU-only autoreset is armed, false after the first GPU touch.
+ */
+static inline bool xe_vma_has_cpu_autoreset_active(struct xe_vma *vma)
+{
+	lockdep_assert_held(&xe_vma_vm(vma)->lock);
+	return vma->cpu_autoreset_active;
+}
+
 struct xe_vma *xe_vm_find_vma_by_addr(struct xe_vm *vm, u64 page_addr);
 
 int xe_vma_need_vram_for_atomic(struct xe_device *xe, struct xe_vma *vma, bool is_atomic);
diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index 635ed29b9a69..e6380458272e 100644
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -52,6 +52,11 @@ struct xe_vm_pgtable_update_op;
 #define XE_VMA_DUMPABLE		(DRM_GPUVA_USERBITS << 8)
 #define XE_VMA_SYSTEM_ALLOCATOR	(DRM_GPUVA_USERBITS << 9)
 #define XE_VMA_MADV_AUTORESET	(DRM_GPUVA_USERBITS << 10)
+/*
+ * Pipeline-only bit used to carry cpu_autoreset_active through MAP/REMAP.
+ * It must not be stored persistently in vma->gpuva.flags.
+ */
+#define XE_VMA_CPU_AUTORESET_ACTIVE	(DRM_GPUVA_USERBITS << 11)
 
 /**
  * struct xe_vma_mem_attr - memory attributes associated with vma
@@ -157,6 +162,14 @@ struct xe_vma {
 	/** @tile_staged: bind is staged for this VMA */
 	u8 tile_staged;
 
+	/**
+	 * @cpu_autoreset_active: CPU mirror VMA has not been GPU-faulted yet.
+	 *
+	 * Set for MADVISE_AUTORESET CPU mirror VMAs and cleared on the first
+	 * successful GPU fault. Protected by vm->lock.
+	 */
+	bool cpu_autoreset_active;
+
 	/**
 	 * @skip_invalidation: Used in madvise to avoid invalidation
 	 * if mem attributes doesn't change
-- 
2.43.0