468     start: VirtAddr,  field
475     pub fn new(start: VirtAddr, size: usize) -> Self {  in new()
476         VirtRegion { start, size }  in new()
481     pub fn start(&self) -> VirtAddr {  in start()  method
482         self.start  in start()
488         return self.start().add(self.size);  in end()
494     pub fn between(start: VirtAddr, end: VirtAddr) -> Option<Self> {  in between()
495         if unlikely(end.data() <= start.data()) {  in between()
498         let size = end.data() - start.data();  in between()
499         return Some(VirtRegion::new(start, size));  in between()
506         let start = self.start.max(other.start);  in intersect()  localVariable
508         return VirtRegion::between(start, end);  in intersect()
513     pub fn set_start(&mut self, start: VirtAddr) {  in set_start()
514         self.start = start;  in set_start()
537         return VirtRegion::new(self.start, round_up_to_page_size(self.size));  in round_up_size_to_page()
548             VirtPageFrame::new(self.start),  in iter_pages()
557         return Self::between(self.start(), region.start());  in before()
577         let offset = vaddr.data() - self.start().data();  in rebase()
578         let new_start = new_base.start().data() + offset;  in rebase()
584         return self.start() <= addr && addr < self.end();  in contains()
590             VirtPageFrame::new(self.start()),  in pages()
598         return self.start.partial_cmp(&other.start);  in partial_cmp()
604         return self.start.cmp(&other.start);  in cmp()