drm/xe: Take ref to VM in delayed snapshot

Kernel BO's don't take a ref to the VM, we need the VM for the
delayed snapshot, so take a ref to the VM in delayed snapshot.

v2:
 - Check for lrc_bo before taking a VM ref (CI)
 - Check lrc_bo->vm before taking / dropping a VM ref (CI)
 - Drop VM in xe_lrc_snapshot_free
v5:
 - Fix commit message wording (Johnathan)

Fixes: 47058633d9c5 ("drm/xe: Move lrc snapshot capturing to xe_lrc.c")
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240801154118.2547543-2-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
index 94ff62e1d95eb1e31f5bfd41a772e8d9662652c1..58121821f0814a35b2947b0417ebdde4b62742c8 100644 (file)
--- a/drivers/gpu/drm/xe/xe_lrc.c
+++ b/drivers/gpu/drm/xe/xe_lrc.c
@@ -1634,6 +1634,9 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
        if (!snapshot)
                return NULL;
 
+       if (lrc->bo && lrc->bo->vm)
+               xe_vm_get(lrc->bo->vm);
+
        snapshot->context_desc = xe_lrc_ggtt_addr(lrc);
        snapshot->indirect_context_desc = xe_lrc_indirect_ring_ggtt_addr(lrc);
        snapshot->head = xe_lrc_ring_head(lrc);
@@ -1653,12 +1656,14 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
 void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot)
 {
        struct xe_bo *bo;
+       struct xe_vm *vm;
        struct iosys_map src;
 
        if (!snapshot)
                return;
 
        bo = snapshot->lrc_bo;
+       vm = bo->vm;
        snapshot->lrc_bo = NULL;
 
        snapshot->lrc_snapshot = kvmalloc(snapshot->lrc_size, GFP_KERNEL);
@@ -1678,6 +1683,8 @@ void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot)
        xe_bo_unlock(bo);
 put_bo:
        xe_bo_put(bo);
+       if (vm)
+               xe_vm_put(vm);
 }
 
 void xe_lrc_snapshot_print(struct xe_lrc_snapshot *snapshot, struct drm_printer *p)
@@ -1727,8 +1734,14 @@ void xe_lrc_snapshot_free(struct xe_lrc_snapshot *snapshot)
                return;
 
        kvfree(snapshot->lrc_snapshot);
-       if (snapshot->lrc_bo)
+       if (snapshot->lrc_bo) {
+               struct xe_vm *vm;
+
+               vm = snapshot->lrc_bo->vm;
                xe_bo_put(snapshot->lrc_bo);
+               if (vm)
+                       xe_vm_put(vm);
+       }
        kfree(snapshot);
 }