| // Copyright 2017 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| //! Track memory regions that are mapped to the guest VM. |
| |
| use std::convert::AsRef; |
| use std::convert::TryFrom; |
| use std::fmt::{self, Display}; |
| use std::mem::size_of; |
| use std::result; |
| use std::sync::Arc; |
| |
| use crate::guest_address::GuestAddress; |
| use base::{pagesize, Error as SysError}; |
| use base::{ |
| AsRawDescriptor, MappedRegion, MemfdSeals, MemoryMapping, MemoryMappingBuilder, MmapError, |
| RawDescriptor, SharedMemory, SharedMemoryUnix, |
| }; |
| use cros_async::{ |
| uring_mem::{self, BorrowedIoVec}, |
| BackingMemory, |
| }; |
| use data_model::volatile_memory::*; |
| use data_model::DataInit; |
| |
| #[derive(Debug)] |
| pub enum Error { |
| DescriptorChainOverflow, |
| InvalidGuestAddress(GuestAddress), |
| MemoryAccess(GuestAddress, MmapError), |
| MemoryMappingFailed(MmapError), |
| MemoryRegionOverlap, |
| MemoryRegionTooLarge(u64), |
| MemoryNotAligned, |
| MemoryCreationFailed(SysError), |
| MemoryAddSealsFailed(SysError), |
| ShortWrite { expected: usize, completed: usize }, |
| ShortRead { expected: usize, completed: usize }, |
| SplitOutOfBounds(usize), |
| VolatileMemoryAccess(VolatileMemoryError), |
| } |
| pub type Result<T> = result::Result<T, Error>; |
| |
| impl std::error::Error for Error {} |
| |
| impl Display for Error { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| use self::Error::*; |
| |
| match self { |
| DescriptorChainOverflow => write!( |
| f, |
| "the combined length of all the buffers in a DescriptorChain is too large" |
| ), |
| InvalidGuestAddress(addr) => write!(f, "invalid guest address {}", addr), |
| MemoryAccess(addr, e) => { |
| write!(f, "invalid guest memory access at addr={}: {}", addr, e) |
| } |
| MemoryMappingFailed(e) => write!(f, "failed to map guest memory: {}", e), |
| MemoryRegionOverlap => write!(f, "memory regions overlap"), |
| MemoryRegionTooLarge(size) => write!(f, "memory region size {} is too large", size), |
| MemoryNotAligned => write!(f, "memfd regions must be page aligned"), |
| MemoryCreationFailed(_) => write!(f, "failed to create memfd region"), |
| MemoryAddSealsFailed(e) => write!(f, "failed to set seals on memfd region: {}", e), |
| ShortWrite { |
| expected, |
| completed, |
| } => write!( |
| f, |
| "incomplete write of {} instead of {} bytes", |
| completed, expected, |
| ), |
| ShortRead { |
| expected, |
| completed, |
| } => write!( |
| f, |
| "incomplete read of {} instead of {} bytes", |
| completed, expected, |
| ), |
| SplitOutOfBounds(off) => write!(f, "DescriptorChain split is out of bounds: {}", off), |
| VolatileMemoryAccess(e) => e.fmt(f), |
| } |
| } |
| } |
| |
| struct MemoryRegion { |
| mapping: MemoryMapping, |
| guest_base: GuestAddress, |
| memfd_offset: u64, |
| } |
| |
| impl MemoryRegion { |
| fn start(&self) -> GuestAddress { |
| self.guest_base |
| } |
| |
| fn end(&self) -> GuestAddress { |
| // unchecked_add is safe as the region bounds were checked when it was created. |
| self.guest_base.unchecked_add(self.mapping.size() as u64) |
| } |
| |
| fn contains(&self, addr: GuestAddress) -> bool { |
| addr >= self.guest_base && addr < self.end() |
| } |
| } |
| |
| /// Tracks a memory region and where it is mapped in the guest, along with a shm |
| /// fd of the underlying memory regions. |
| #[derive(Clone)] |
| pub struct GuestMemory { |
| regions: Arc<Vec<MemoryRegion>>, |
| memfd: Arc<SharedMemory>, |
| } |
| |
| impl AsRawDescriptor for GuestMemory { |
| fn as_raw_descriptor(&self) -> RawDescriptor { |
| self.memfd.as_raw_descriptor() |
| } |
| } |
| |
| impl AsRef<SharedMemory> for GuestMemory { |
| fn as_ref(&self) -> &SharedMemory { |
| &self.memfd |
| } |
| } |
| |
| impl GuestMemory { |
| /// Creates backing memfd for GuestMemory regions |
| fn create_memfd(ranges: &[(GuestAddress, u64)]) -> Result<SharedMemory> { |
| let mut aligned_size = 0; |
| let pg_size = pagesize(); |
| for range in ranges { |
| if range.1 % pg_size as u64 != 0 { |
| return Err(Error::MemoryNotAligned); |
| } |
| |
| aligned_size += range.1; |
| } |
| |
| let mut seals = MemfdSeals::new(); |
| |
| seals.set_shrink_seal(); |
| seals.set_grow_seal(); |
| seals.set_seal_seal(); |
| |
| let mut memfd = SharedMemory::named("crosvm_guest", aligned_size) |
| .map_err(Error::MemoryCreationFailed)?; |
| memfd |
| .add_seals(seals) |
| .map_err(Error::MemoryAddSealsFailed)?; |
| |
| Ok(memfd) |
| } |
| |
| /// Creates a container for guest memory regions. |
| /// Valid memory regions are specified as a Vec of (Address, Size) tuples sorted by Address. |
| pub fn new(ranges: &[(GuestAddress, u64)]) -> Result<GuestMemory> { |
| // Create memfd |
| |
| let memfd = GuestMemory::create_memfd(ranges)?; |
| // Create memory regions |
| let mut regions = Vec::<MemoryRegion>::new(); |
| let mut offset = 0; |
| |
| for range in ranges { |
| if let Some(last) = regions.last() { |
| if last |
| .guest_base |
| .checked_add(last.mapping.size() as u64) |
| .map_or(true, |a| a > range.0) |
| { |
| return Err(Error::MemoryRegionOverlap); |
| } |
| } |
| |
| let size = |
| usize::try_from(range.1).map_err(|_| Error::MemoryRegionTooLarge(range.1))?; |
| let mapping = MemoryMappingBuilder::new(size) |
| .from_descriptor(&memfd) |
| .offset(offset) |
| .build() |
| .map_err(Error::MemoryMappingFailed)?; |
| regions.push(MemoryRegion { |
| mapping, |
| guest_base: range.0, |
| memfd_offset: offset, |
| }); |
| |
| offset += size as u64; |
| } |
| |
| Ok(GuestMemory { |
| regions: Arc::new(regions), |
| memfd: Arc::new(memfd), |
| }) |
| } |
| |
| /// Returns the end address of memory. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_end_addr() -> Result<(), ()> { |
| /// let start_addr = GuestAddress(0x1000); |
| /// let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// assert_eq!(start_addr.checked_add(0x400), Some(gm.end_addr())); |
| /// Ok(()) |
| /// # } |
| /// ``` |
| pub fn end_addr(&self) -> GuestAddress { |
| self.regions |
| .iter() |
| .max_by_key(|region| region.start()) |
| .map_or(GuestAddress(0), MemoryRegion::end) |
| } |
| |
| /// Returns the total size of memory in bytes. |
| pub fn memory_size(&self) -> u64 { |
| self.regions |
| .iter() |
| .map(|region| region.mapping.size() as u64) |
| .sum() |
| } |
| |
| /// Returns true if the given address is within the memory range available to the guest. |
| pub fn address_in_range(&self, addr: GuestAddress) -> bool { |
| self.regions.iter().any(|region| region.contains(addr)) |
| } |
| |
| /// Returns true if the given range (start, end) is overlap with the memory range |
| /// available to the guest. |
| pub fn range_overlap(&self, start: GuestAddress, end: GuestAddress) -> bool { |
| self.regions |
| .iter() |
| .any(|region| region.start() < end && start < region.end()) |
| } |
| |
| /// Returns the address plus the offset if it is in range. |
| pub fn checked_offset(&self, addr: GuestAddress, offset: u64) -> Option<GuestAddress> { |
| addr.checked_add(offset).and_then(|a| { |
| if self.address_in_range(a) { |
| Some(a) |
| } else { |
| None |
| } |
| }) |
| } |
| |
| /// Returns the size of the memory region in bytes. |
| pub fn num_regions(&self) -> u64 { |
| self.regions.len() as u64 |
| } |
| |
| /// Madvise away the address range in the host that is associated with the given guest range. |
| pub fn remove_range(&self, addr: GuestAddress, count: u64) -> Result<()> { |
| self.do_in_region(addr, move |mapping, offset| { |
| mapping |
| .remove_range(offset, count as usize) |
| .map_err(|e| Error::MemoryAccess(addr, e)) |
| }) |
| } |
| |
| /// Perform the specified action on each region's addresses. |
| /// |
| /// Callback is called with arguments: |
| /// * index: usize |
| /// * guest_addr : GuestAddress |
| /// * size: usize |
| /// * host_addr: usize |
| /// * memfd_offset: usize |
| pub fn with_regions<F, E>(&self, mut cb: F) -> result::Result<(), E> |
| where |
| F: FnMut(usize, GuestAddress, usize, usize, u64) -> result::Result<(), E>, |
| { |
| for (index, region) in self.regions.iter().enumerate() { |
| cb( |
| index, |
| region.start(), |
| region.mapping.size(), |
| region.mapping.as_ptr() as usize, |
| region.memfd_offset, |
| )?; |
| } |
| Ok(()) |
| } |
| |
| /// Writes a slice to guest memory at the specified guest address. |
| /// Returns the number of bytes written. The number of bytes written can |
| /// be less than the length of the slice if there isn't enough room in the |
| /// memory region. |
| /// |
| /// # Examples |
| /// * Write a slice at guestaddress 0x200. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_write_u64() -> Result<(), ()> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// let res = gm.write_at_addr(&[1,2,3,4,5], GuestAddress(0x200)).map_err(|_| ())?; |
| /// assert_eq!(5, res); |
| /// Ok(()) |
| /// # } |
| /// ``` |
| pub fn write_at_addr(&self, buf: &[u8], guest_addr: GuestAddress) -> Result<usize> { |
| self.do_in_region(guest_addr, move |mapping, offset| { |
| mapping |
| .write_slice(buf, offset) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Writes the entire contents of a slice to guest memory at the specified |
| /// guest address. |
| /// |
| /// Returns an error if there isn't enough room in the memory region to |
| /// complete the entire write. Part of the data may have been written |
| /// nevertheless. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use vm_memory::{guest_memory, GuestAddress, GuestMemory}; |
| /// |
| /// fn test_write_all() -> guest_memory::Result<()> { |
| /// let ranges = &[(GuestAddress(0x1000), 0x400)]; |
| /// let gm = GuestMemory::new(ranges)?; |
| /// gm.write_all_at_addr(b"zyxwvut", GuestAddress(0x1200)) |
| /// } |
| /// ``` |
| pub fn write_all_at_addr(&self, buf: &[u8], guest_addr: GuestAddress) -> Result<()> { |
| let expected = buf.len(); |
| let completed = self.write_at_addr(buf, guest_addr)?; |
| if expected == completed { |
| Ok(()) |
| } else { |
| Err(Error::ShortWrite { |
| expected, |
| completed, |
| }) |
| } |
| } |
| |
| /// Reads to a slice from guest memory at the specified guest address. |
| /// Returns the number of bytes read. The number of bytes read can |
| /// be less than the length of the slice if there isn't enough room in the |
| /// memory region. |
| /// |
| /// # Examples |
| /// * Read a slice of length 16 at guestaddress 0x200. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_write_u64() -> Result<(), ()> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// let buf = &mut [0u8; 16]; |
| /// let res = gm.read_at_addr(buf, GuestAddress(0x200)).map_err(|_| ())?; |
| /// assert_eq!(16, res); |
| /// Ok(()) |
| /// # } |
| /// ``` |
| pub fn read_at_addr(&self, buf: &mut [u8], guest_addr: GuestAddress) -> Result<usize> { |
| self.do_in_region(guest_addr, move |mapping, offset| { |
| mapping |
| .read_slice(buf, offset) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Reads from guest memory at the specified address to fill the entire |
| /// buffer. |
| /// |
| /// Returns an error if there isn't enough room in the memory region to fill |
| /// the entire buffer. Part of the buffer may have been filled nevertheless. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use vm_memory::{guest_memory, GuestAddress, GuestMemory}; |
| /// |
| /// fn test_read_exact() -> guest_memory::Result<()> { |
| /// let ranges = &[(GuestAddress(0x1000), 0x400)]; |
| /// let gm = GuestMemory::new(ranges)?; |
| /// let mut buffer = [0u8; 0x200]; |
| /// gm.read_exact_at_addr(&mut buffer, GuestAddress(0x1200)) |
| /// } |
| /// ``` |
| pub fn read_exact_at_addr(&self, buf: &mut [u8], guest_addr: GuestAddress) -> Result<()> { |
| let expected = buf.len(); |
| let completed = self.read_at_addr(buf, guest_addr)?; |
| if expected == completed { |
| Ok(()) |
| } else { |
| Err(Error::ShortRead { |
| expected, |
| completed, |
| }) |
| } |
| } |
| |
| /// Reads an object from guest memory at the given guest address. |
| /// Reading from a volatile area isn't strictly safe as it could change |
| /// mid-read. However, as long as the type T is plain old data and can |
| /// handle random initialization, everything will be OK. |
| /// |
| /// # Examples |
| /// * Read a u64 from two areas of guest memory backed by separate mappings. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_read_u64() -> Result<u64, ()> { |
| /// # let start_addr1 = GuestAddress(0x0); |
| /// # let start_addr2 = GuestAddress(0x400); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr1, 0x400), (start_addr2, 0x400)]) |
| /// # .map_err(|_| ())?; |
| /// let num1: u64 = gm.read_obj_from_addr(GuestAddress(32)).map_err(|_| ())?; |
| /// let num2: u64 = gm.read_obj_from_addr(GuestAddress(0x400+32)).map_err(|_| ())?; |
| /// # Ok(num1 + num2) |
| /// # } |
| /// ``` |
| pub fn read_obj_from_addr<T: DataInit>(&self, guest_addr: GuestAddress) -> Result<T> { |
| self.do_in_region(guest_addr, |mapping, offset| { |
| mapping |
| .read_obj(offset) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Writes an object to the memory region at the specified guest address. |
| /// Returns Ok(()) if the object fits, or Err if it extends past the end. |
| /// |
| /// # Examples |
| /// * Write a u64 at guest address 0x1100. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_write_u64() -> Result<(), ()> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// gm.write_obj_at_addr(55u64, GuestAddress(0x1100)) |
| /// .map_err(|_| ()) |
| /// # } |
| /// ``` |
| pub fn write_obj_at_addr<T: DataInit>(&self, val: T, guest_addr: GuestAddress) -> Result<()> { |
| self.do_in_region(guest_addr, move |mapping, offset| { |
| mapping |
| .write_obj(val, offset) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Returns a `VolatileSlice` of `len` bytes starting at `addr`. Returns an error if the slice |
| /// is not a subset of this `GuestMemory`. |
| /// |
| /// # Examples |
| /// * Write `99` to 30 bytes starting at guest address 0x1010. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory, GuestMemoryError}; |
| /// # fn test_volatile_slice() -> Result<(), GuestMemoryError> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)])?; |
| /// let vslice = gm.get_slice_at_addr(GuestAddress(0x1010), 30)?; |
| /// vslice.write_bytes(99); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| pub fn get_slice_at_addr(&self, addr: GuestAddress, len: usize) -> Result<VolatileSlice> { |
| self.regions |
| .iter() |
| .find(|region| region.contains(addr)) |
| .ok_or(Error::InvalidGuestAddress(addr)) |
| .and_then(|region| { |
| // The cast to a usize is safe here because we know that `region.contains(addr)` and |
| // it's not possible for a memory region to be larger than what fits in a usize. |
| region |
| .mapping |
| .get_slice(addr.offset_from(region.start()) as usize, len) |
| .map_err(Error::VolatileMemoryAccess) |
| }) |
| } |
| |
| /// Returns a `VolatileRef` to an object at `addr`. Returns Ok(()) if the object fits, or Err if |
| /// it extends past the end. |
| /// |
| /// # Examples |
| /// * Get a &u64 at offset 0x1010. |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory, GuestMemoryError}; |
| /// # fn test_ref_u64() -> Result<(), GuestMemoryError> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let mut gm = GuestMemory::new(&vec![(start_addr, 0x400)])?; |
| /// gm.write_obj_at_addr(47u64, GuestAddress(0x1010))?; |
| /// let vref = gm.get_ref_at_addr::<u64>(GuestAddress(0x1010))?; |
| /// assert_eq!(vref.load(), 47u64); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| pub fn get_ref_at_addr<T: DataInit>(&self, addr: GuestAddress) -> Result<VolatileRef<T>> { |
| let buf = self.get_slice_at_addr(addr, size_of::<T>())?; |
| // Safe because we have know that `buf` is at least `size_of::<T>()` bytes and that the |
| // returned reference will not outlive this `GuestMemory`. |
| Ok(unsafe { VolatileRef::new(buf.as_mut_ptr() as *mut T) }) |
| } |
| |
| /// Reads data from a file descriptor and writes it to guest memory. |
| /// |
| /// # Arguments |
| /// * `guest_addr` - Begin writing memory at this offset. |
| /// * `src` - Read from `src` to memory. |
| /// * `count` - Read `count` bytes from `src` to memory. |
| /// |
| /// # Examples |
| /// |
| /// * Read bytes from /dev/urandom |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # use std::fs::File; |
| /// # use std::path::Path; |
| /// # fn test_read_random() -> Result<u32, ()> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// let mut file = File::open(Path::new("/dev/urandom")).map_err(|_| ())?; |
| /// let addr = GuestAddress(0x1010); |
| /// gm.read_to_memory(addr, &mut file, 128).map_err(|_| ())?; |
| /// let read_addr = addr.checked_add(8).ok_or(())?; |
| /// let rand_val: u32 = gm.read_obj_from_addr(read_addr).map_err(|_| ())?; |
| /// # Ok(rand_val) |
| /// # } |
| /// ``` |
| pub fn read_to_memory( |
| &self, |
| guest_addr: GuestAddress, |
| src: &dyn AsRawDescriptor, |
| count: usize, |
| ) -> Result<()> { |
| self.do_in_region(guest_addr, move |mapping, offset| { |
| mapping |
| .read_to_memory(offset, src, count) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Writes data from memory to a file descriptor. |
| /// |
| /// # Arguments |
| /// * `guest_addr` - Begin reading memory from this offset. |
| /// * `dst` - Write from memory to `dst`. |
| /// * `count` - Read `count` bytes from memory to `src`. |
| /// |
| /// # Examples |
| /// |
| /// * Write 128 bytes to /dev/null |
| /// |
| /// ``` |
| /// # use base::MemoryMapping; |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # use std::fs::File; |
| /// # use std::path::Path; |
| /// # fn test_write_null() -> Result<(), ()> { |
| /// # let start_addr = GuestAddress(0x1000); |
| /// # let gm = GuestMemory::new(&vec![(start_addr, 0x400)]).map_err(|_| ())?; |
| /// let mut file = File::open(Path::new("/dev/null")).map_err(|_| ())?; |
| /// let addr = GuestAddress(0x1010); |
| /// gm.write_from_memory(addr, &mut file, 128).map_err(|_| ())?; |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| pub fn write_from_memory( |
| &self, |
| guest_addr: GuestAddress, |
| dst: &dyn AsRawDescriptor, |
| count: usize, |
| ) -> Result<()> { |
| self.do_in_region(guest_addr, move |mapping, offset| { |
| mapping |
| .write_from_memory(offset, dst, count) |
| .map_err(|e| Error::MemoryAccess(guest_addr, e)) |
| }) |
| } |
| |
| /// Convert a GuestAddress into a pointer in the address space of this |
| /// process. This should only be necessary for giving addresses to the |
| /// kernel, as with vhost ioctls. Normal reads/writes to guest memory should |
| /// be done through `write_from_memory`, `read_obj_from_addr`, etc. |
| /// |
| /// # Arguments |
| /// * `guest_addr` - Guest address to convert. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// # fn test_host_addr() -> Result<(), ()> { |
| /// let start_addr = GuestAddress(0x1000); |
| /// let mut gm = GuestMemory::new(&vec![(start_addr, 0x500)]).map_err(|_| ())?; |
| /// let addr = gm.get_host_address(GuestAddress(0x1200)).unwrap(); |
| /// println!("Host address is {:p}", addr); |
| /// Ok(()) |
| /// # } |
| /// ``` |
| pub fn get_host_address(&self, guest_addr: GuestAddress) -> Result<*const u8> { |
| self.do_in_region(guest_addr, |mapping, offset| { |
| // This is safe; `do_in_region` already checks that offset is in |
| // bounds. |
| Ok(unsafe { mapping.as_ptr().add(offset) } as *const u8) |
| }) |
| } |
| |
| pub fn do_in_region<F, T>(&self, guest_addr: GuestAddress, cb: F) -> Result<T> |
| where |
| F: FnOnce(&MemoryMapping, usize) -> Result<T>, |
| { |
| self.regions |
| .iter() |
| .find(|region| region.contains(guest_addr)) |
| .ok_or(Error::InvalidGuestAddress(guest_addr)) |
| .and_then(|region| { |
| cb( |
| ®ion.mapping, |
| guest_addr.offset_from(region.start()) as usize, |
| ) |
| }) |
| } |
| |
| /// Convert a GuestAddress into an offset within self.memfd. |
| /// |
| /// Due to potential gaps within GuestMemory, it is helpful to know the |
| /// offset within the memfd where a given address is found. This offset |
| /// can then be passed to another process mapping the memfd to read data |
| /// starting at that address. |
| /// |
| /// # Arguments |
| /// * `guest_addr` - Guest address to convert. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # use vm_memory::{GuestAddress, GuestMemory}; |
| /// let addr_a = GuestAddress(0x1000); |
| /// let addr_b = GuestAddress(0x8000); |
| /// let mut gm = GuestMemory::new(&vec![ |
| /// (addr_a, 0x2000), |
| /// (addr_b, 0x3000)]).expect("failed to create GuestMemory"); |
| /// let offset = gm.offset_from_base(GuestAddress(0x9500)) |
| /// .expect("failed to get offset"); |
| /// assert_eq!(offset, 0x3500); |
| /// ``` |
| pub fn offset_from_base(&self, guest_addr: GuestAddress) -> Result<u64> { |
| self.regions |
| .iter() |
| .find(|region| region.contains(guest_addr)) |
| .ok_or(Error::InvalidGuestAddress(guest_addr)) |
| .map(|region| region.memfd_offset + guest_addr.offset_from(region.start())) |
| } |
| } |
| |
| // It is safe to implement BackingMemory because GuestMemory can be mutated any time already. |
| unsafe impl BackingMemory for GuestMemory { |
| fn get_iovec<'s>( |
| &'s self, |
| mem_range: cros_async::MemRegion, |
| ) -> uring_mem::Result<uring_mem::BorrowedIoVec<'s>> { |
| let vs = self |
| .get_slice_at_addr(GuestAddress(mem_range.offset as u64), mem_range.len) |
| .map_err(|_| uring_mem::Error::InvalidOffset(mem_range.offset, mem_range.len))?; |
| // Safe because 'vs' is valid in the backing memory as checked above. |
| unsafe { |
| Ok(BorrowedIoVec::from_raw_parts( |
| vs.as_mut_ptr(), |
| vs.size() as usize, |
| )) |
| } |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| use base::kernel_has_memfd; |
| |
| #[test] |
| fn test_alignment() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| |
| assert!(GuestMemory::new(&[(start_addr1, 0x100), (start_addr2, 0x400)]).is_err()); |
| assert!(GuestMemory::new(&[(start_addr1, 0x1000), (start_addr2, 0x1000)]).is_ok()); |
| } |
| |
| #[test] |
| fn two_regions() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x4000); |
| assert!(GuestMemory::new(&[(start_addr1, 0x4000), (start_addr2, 0x4000)]).is_ok()); |
| } |
| |
| #[test] |
| fn overlap_memory() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| assert!(GuestMemory::new(&[(start_addr1, 0x2000), (start_addr2, 0x2000)]).is_err()); |
| } |
| |
| #[test] |
| fn region_hole() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x4000); |
| let gm = GuestMemory::new(&[(start_addr1, 0x2000), (start_addr2, 0x2000)]).unwrap(); |
| assert_eq!(gm.address_in_range(GuestAddress(0x1000)), true); |
| assert_eq!(gm.address_in_range(GuestAddress(0x3000)), false); |
| assert_eq!(gm.address_in_range(GuestAddress(0x5000)), true); |
| assert_eq!(gm.address_in_range(GuestAddress(0x6000)), false); |
| assert_eq!(gm.address_in_range(GuestAddress(0x6000)), false); |
| assert_eq!( |
| gm.range_overlap(GuestAddress(0x1000), GuestAddress(0x3000)), |
| true |
| ); |
| assert_eq!( |
| gm.range_overlap(GuestAddress(0x3000), GuestAddress(0x4000)), |
| false |
| ); |
| assert_eq!( |
| gm.range_overlap(GuestAddress(0x3000), GuestAddress(0x7000)), |
| true |
| ); |
| assert!(gm.checked_offset(GuestAddress(0x1000), 0x1000).is_none()); |
| assert!(gm.checked_offset(GuestAddress(0x5000), 0x800).is_some()); |
| assert!(gm.checked_offset(GuestAddress(0x5000), 0x1000).is_none()); |
| } |
| |
| #[test] |
| fn test_read_u64() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| let gm = GuestMemory::new(&[(start_addr1, 0x1000), (start_addr2, 0x1000)]).unwrap(); |
| |
| let val1: u64 = 0xaa55aa55aa55aa55; |
| let val2: u64 = 0x55aa55aa55aa55aa; |
| gm.write_obj_at_addr(val1, GuestAddress(0x500)).unwrap(); |
| gm.write_obj_at_addr(val2, GuestAddress(0x1000 + 32)) |
| .unwrap(); |
| let num1: u64 = gm.read_obj_from_addr(GuestAddress(0x500)).unwrap(); |
| let num2: u64 = gm.read_obj_from_addr(GuestAddress(0x1000 + 32)).unwrap(); |
| assert_eq!(val1, num1); |
| assert_eq!(val2, num2); |
| } |
| |
| #[test] |
| fn test_ref_load_u64() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| let gm = GuestMemory::new(&[(start_addr1, 0x1000), (start_addr2, 0x1000)]).unwrap(); |
| |
| let val1: u64 = 0xaa55aa55aa55aa55; |
| let val2: u64 = 0x55aa55aa55aa55aa; |
| gm.write_obj_at_addr(val1, GuestAddress(0x500)).unwrap(); |
| gm.write_obj_at_addr(val2, GuestAddress(0x1000 + 32)) |
| .unwrap(); |
| let num1: u64 = gm.get_ref_at_addr(GuestAddress(0x500)).unwrap().load(); |
| let num2: u64 = gm |
| .get_ref_at_addr(GuestAddress(0x1000 + 32)) |
| .unwrap() |
| .load(); |
| assert_eq!(val1, num1); |
| assert_eq!(val2, num2); |
| } |
| |
| #[test] |
| fn test_ref_store_u64() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| let gm = GuestMemory::new(&[(start_addr1, 0x1000), (start_addr2, 0x1000)]).unwrap(); |
| |
| let val1: u64 = 0xaa55aa55aa55aa55; |
| let val2: u64 = 0x55aa55aa55aa55aa; |
| gm.get_ref_at_addr(GuestAddress(0x500)).unwrap().store(val1); |
| gm.get_ref_at_addr(GuestAddress(0x1000 + 32)) |
| .unwrap() |
| .store(val2); |
| let num1: u64 = gm.read_obj_from_addr(GuestAddress(0x500)).unwrap(); |
| let num2: u64 = gm.read_obj_from_addr(GuestAddress(0x1000 + 32)).unwrap(); |
| assert_eq!(val1, num1); |
| assert_eq!(val2, num2); |
| } |
| |
| #[test] |
| fn test_memory_size() { |
| let start_region1 = GuestAddress(0x0); |
| let size_region1 = 0x1000; |
| let start_region2 = GuestAddress(0x10000); |
| let size_region2 = 0x2000; |
| let gm = GuestMemory::new(&[(start_region1, size_region1), (start_region2, size_region2)]) |
| .unwrap(); |
| |
| let mem_size = gm.memory_size(); |
| assert_eq!(mem_size, size_region1 + size_region2); |
| } |
| |
| // Get the base address of the mapping for a GuestAddress. |
| fn get_mapping(mem: &GuestMemory, addr: GuestAddress) -> Result<*const u8> { |
| mem.do_in_region(addr, |mapping, _| Ok(mapping.as_ptr() as *const u8)) |
| } |
| |
| #[test] |
| fn guest_to_host() { |
| let start_addr1 = GuestAddress(0x0); |
| let start_addr2 = GuestAddress(0x1000); |
| let mem = GuestMemory::new(&[(start_addr1, 0x1000), (start_addr2, 0x4000)]).unwrap(); |
| |
| // Verify the host addresses match what we expect from the mappings. |
| let addr1_base = get_mapping(&mem, start_addr1).unwrap(); |
| let addr2_base = get_mapping(&mem, start_addr2).unwrap(); |
| let host_addr1 = mem.get_host_address(start_addr1).unwrap(); |
| let host_addr2 = mem.get_host_address(start_addr2).unwrap(); |
| assert_eq!(host_addr1, addr1_base); |
| assert_eq!(host_addr2, addr2_base); |
| |
| // Check that a bad address returns an error. |
| let bad_addr = GuestAddress(0x123456); |
| assert!(mem.get_host_address(bad_addr).is_err()); |
| } |
| |
| #[test] |
| fn memfd_offset() { |
| if !kernel_has_memfd() { |
| return; |
| } |
| |
| let start_region1 = GuestAddress(0x0); |
| let size_region1 = 0x1000; |
| let start_region2 = GuestAddress(0x10000); |
| let size_region2 = 0x2000; |
| let gm = GuestMemory::new(&[(start_region1, size_region1), (start_region2, size_region2)]) |
| .unwrap(); |
| |
| gm.write_obj_at_addr(0x1337u16, GuestAddress(0x0)).unwrap(); |
| gm.write_obj_at_addr(0x0420u16, GuestAddress(0x10000)) |
| .unwrap(); |
| |
| let _ = gm.with_regions::<_, ()>(|index, _, size, _, memfd_offset| { |
| let mmap = MemoryMappingBuilder::new(size) |
| .from_descriptor(gm.as_ref()) |
| .offset(memfd_offset) |
| .build() |
| .unwrap(); |
| |
| if index == 0 { |
| assert!(mmap.read_obj::<u16>(0x0).unwrap() == 0x1337u16); |
| } |
| |
| if index == 1 { |
| assert!(mmap.read_obj::<u16>(0x0).unwrap() == 0x0420u16); |
| } |
| |
| Ok(()) |
| }); |
| } |
| } |