Thank you for providing the code and identifying the potential vulnerability. Based on the information given, here are five possible patches to address the CWE-787 (Out-of-bounds Write) vulnerability in the specified line:

Patch 1: Add bounds checking before accessing the array
```c
97 		if (level > 0 && level <= num_level) {
98 			entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level - 1) *
99 							  XE_PAGE_SIZE, pat_index);
100 		} else {
101 			xe_err(xe, "Invalid level: %u\n", level);
102 			return -EINVAL;
103 		}
```

Patch 2: Use a safer arithmetic operation
```c
97 		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level > 0 ? level - 1 : 0) *
98 						  XE_PAGE_SIZE, pat_index);
```

Patch 3: Ensure 'level' is within valid range before the loop
```c
91 	for (level = 1; level < num_level && level > 0; level++) {
```

Patch 4: Use unsigned integer for 'level' to prevent negative values
```c
8 	u32 map_ofs, i;
9 	u32 level;
```

Patch 5: Add an assertion to catch potential issues during development
```c
97 		xe_assert(xe, level > 0 && level <= num_level);
98 		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level - 1) *
99 						  XE_PAGE_SIZE, pat_index);
```

Each of these patches aims to prevent potential out-of-bounds access by ensuring that 'level' is within a valid range before it's used in the calculation. The most appropriate patch would depend on the specific requirements and constraints of the project.