Struct ostd::mm::VmSpace

pub struct VmSpace { /* private fields */ }

Virtual memory space.

A virtual memory space (VmSpace) can be created and assigned to a user space so that the virtual memory of the user space can be manipulated safely. For example, given an arbitrary user-space pointer, one can read and write the memory location referred to by the user-space pointer without the risk of breaking the memory safety of the kernel space.

A newly-created VmSpace is not backed by any physical memory pages. To provide memory pages for a VmSpace, one can allocate and map physical memory (Frames) to the VmSpace.

A VmSpace can also attach a page fault handler, which will be invoked to handle page faults generated from user space.

A VmSpace can also attach a page fault handler, which will be invoked to handle page faults generated from user space.

Implementations

impl VmSpace

pub fn new() -> Self

Creates a new VM address space.

pub fn register_page_fault_handler( &self, func: fn(_: &VmSpace, _: &CpuExceptionInfo) -> Result<(), ()>, )

Registers the page fault handler in this VmSpace.

The page fault handler of a VmSpace can only be initialized once. If it has been initialized before, calling this method will have no effect.

pub fn map(&self, frames: FrameVec, options: &VmMapOptions) -> Result<Vaddr>

Maps some physical memory pages into the VM space according to the given options, returning the address where the mapping is created.

The ownership of the frames will be transferred to the VmSpace.

For more information, see VmMapOptions.

pub fn query_range(&self, range: &Range<Vaddr>) -> Result<VmQueryIter<'_>>

Queries about a range of virtual memory. You will get an iterator of VmQueryResult which contains the information of each parts of the range.

pub fn query(&self, vaddr: Vaddr) -> Result<Option<PageProperty>>

Queries about the mapping information about a byte in virtual memory. This is more handy than query_range, but less efficient if you want to query in a batch.

pub fn unmap(&self, range: &Range<Vaddr>) -> Result<()>

Unmaps the physical memory pages within the VM address range.

The range is allowed to contain gaps, where no physical memory pages are mapped.

pub fn clear(&self)

Clears all mappings

pub fn protect( &self, range: &Range<Vaddr>, op: impl FnMut(&mut PageProperty), ) -> Result<()>

Updates the VM protection permissions within the VM address range.

If any of the page in the given range is not mapped, it is skipped. The method panics when virtual address is not aligned to base page size.

It is guarenteed that the operation is called once for each valid page found in the range.

TODO: It returns error when invalid operations such as protect partial huge page happens, and efforts are not reverted, leaving us in a bad state.

pub fn fork_copy_on_write(&self) -> Self

Forks a new VM space with copy-on-write semantics.

Both the parent and the newly forked VM space will be marked as read-only. And both the VM space will take handles to the same physical memory pages.

pub fn reader( &self, vaddr: Vaddr, len: usize, ) -> Result<VmReader<'_, UserSpace>>

Creates a reader to read data from the user space of the current task.

Returns Err if this VmSpace is not belonged to the user space of the current task or the vaddr and len do not represent a user space memory range.

pub fn writer( &self, vaddr: Vaddr, len: usize, ) -> Result<VmWriter<'_, UserSpace>>

Creates a writer to write data into the user space.

Returns Err if this VmSpace is not belonged to the user space of the current task or the vaddr and len do not represent a user space memory range.

Trait Implementations

impl Default for VmSpace

fn default() -> Self

Returns the “default value” for a type.