Fix safety comment in iovec.rs
In I forgot to adjust it
@@ -136,8 +136,8 @@ impl IoVecBuffer {
// its boundaries) and `start` is less than `seg.iov_len`.
//
// The call to `copy_nonoverlapping` is safe because:
- // 1. `buf_ptr` is a pointer valid for writing `buf_end - buf_start + 1` bytes.
- // 2. `seg_ptr` is a pointer valid for reading `buf_end - buf_start + 1` bytes.
+ // 1. `buf_ptr` is a pointer valid for writing `buf_end - buf_start` bytes.
+ // 2. `seg_ptr` is a pointer valid for reading `buf_end - buf_start` bytes.
// 3. Both pointers pointers are pointing to `u8`, so they are properly aligned.
// 4. The memory regions these pointers point to are not overlapping. `seg_ptr` points
// to guest physical memory, whereas `buf_ptr` to Firecracaker-owned memory.
