drm/xe/xe_migrate: Cast to output precision before multiplying operands

Addressing potential overflow in result of  multiplication of two lower
precision (u32) operands before widening it to higher precision
(u64).

-v2
Fix commit message and description. (Rodrigo)

Cc: Rodrigo Vivi <[email protected]>
Signed-off-by: Himal Prasad Ghimiray <[email protected]>
Reviewed-by: Rodrigo Vivi <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Rodrigo Vivi <[email protected]>
(cherry picked from commit 3482096)
Signed-off-by: Lucas De Marchi <[email protected]>

Author: hghimira

drivers/gpu/drm/xe/xe_migrate.c

@@ -227,15 +227,15 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
 		if (vm->flags & XE_VM_FLAG_64K && level == 1)
 			flags = XE_PDE_64K;
 
-		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level - 1) *
+		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (u64)(level - 1) *
 						  XE_PAGE_SIZE, pat_index);
 		xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE * level, u64,
 			  entry | flags);
 	}
 
 	/* Write PDE's that point to our BO. */
 	for (i = 0; i < num_entries - num_level; i++) {
-		entry = vm->pt_ops->pde_encode_bo(bo, i * XE_PAGE_SIZE,
+		entry = vm->pt_ops->pde_encode_bo(bo, (u64)i * XE_PAGE_SIZE,
 						  pat_index);
 
 		xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE +
@@ -291,7 +291,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
 #define VM_SA_UPDATE_UNIT_SIZE		(XE_PAGE_SIZE / NUM_VMUSA_UNIT_PER_PAGE)
 #define NUM_VMUSA_WRITES_PER_UNIT	(VM_SA_UPDATE_UNIT_SIZE / sizeof(u64))
 	drm_suballoc_manager_init(&m->vm_update_sa,
-				  (map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
+				  (size_t)(map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
 				  NUM_VMUSA_UNIT_PER_PAGE, 0);
 
 	m->pt_bo = bo;
@@ -490,7 +490,7 @@ static void emit_pte(struct xe_migrate *m,
 	struct xe_vm *vm = m->q->vm;
 	u16 pat_index;
 	u32 ptes;
-	u64 ofs = at_pt * XE_PAGE_SIZE;
+	u64 ofs = (u64)at_pt * XE_PAGE_SIZE;
 	u64 cur_ofs;
 
 	/* Indirect access needs compression enabled uncached PAT index */