osiris/mem/vmm/
nommu.rs

1use core::ptr::copy_nonoverlapping;
2
3use hal::mem::{PhysAddr, VirtAddr};
4
5use crate::{
6    error::Result,
7    mem::{
8        alloc::{Allocator, bestfit},
9        pfa, vmm,
10    },
11};
12
13pub struct AddressSpace {
14    begin: PhysAddr,
15    #[allow(dead_code)]
16    end: PhysAddr,
17    allocator: bestfit::BestFitAllocator,
18}
19
20impl vmm::AddressSpacelike for AddressSpace {
21    fn new(pgs: usize) -> Result<Self> {
22        let begin = pfa::alloc_page(pgs).ok_or(kerr!(OutOfMemory))?;
23        let end = begin
24            .checked_add(pgs * pfa::PAGE_SIZE)
25            .ok_or(kerr!(OutOfMemory))?;
26
27        let mut allocator = bestfit::BestFitAllocator::new();
28        unsafe { allocator.add_range(&(begin..end))? };
29
30        Ok(Self {
31            begin,
32            end,
33            allocator,
34        })
35    }
36
37    fn map(&mut self, region: vmm::Region) -> Result<PhysAddr> {
38        let req = region.start.and_then(|virt| self.virt_to_phys(virt));
39        // TODO: per page align
40        let align = core::mem::align_of::<u128>();
41        let start = self.allocator.malloc::<u8>(region.len(), align, req)?;
42
43        match region.backing {
44            vmm::Backing::Anon(phys) => {
45                unsafe {
46                    copy_nonoverlapping(phys.as_mut_ptr::<u8>(), start.as_ptr(), region.len())
47                };
48            }
49            vmm::Backing::Zeroed => {
50                unsafe { core::ptr::write_bytes(start.as_ptr(), 0, region.len()) };
51            }
52            vmm::Backing::Uninit => {}
53        }
54
55        Ok(start.into())
56    }
57
58    fn unmap(&mut self, _region: &vmm::Region) -> Result<()> {
59        Ok(())
60    }
61
62    fn protect(&mut self, _region: &vmm::Region, _perms: vmm::Perms) -> Result<()> {
63        Ok(())
64    }
65
66    fn phys_to_virt(&self, addr: PhysAddr) -> Option<VirtAddr> {
67        addr.checked_sub(self.begin.as_usize())
68            .map(|phys| VirtAddr::new(phys.as_usize()))
69    }
70
71    fn virt_to_phys(&self, addr: VirtAddr) -> Option<PhysAddr> {
72        self.begin.checked_add(addr.as_usize())
73    }
74
75    fn end(&self) -> VirtAddr {
76        // This should always succeed.
77        self.phys_to_virt(self.end).unwrap()
78    }
79
80    fn activate(&self) -> Result<()> {
81        Ok(())
82    }
83}
osiris/mem/vmm/nommu.rs

osiris/mem/vmm/
nommu.rs
