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* More use of `anyhow`.
* Change `make_accessible` into `protect_linear_memory` to better demonstrate
  what it is used for; this will make the uffd implementation make a little
  more sense.
* Remove `create_memory_map` in favor of just creating the `Mmap` instances in
  the pooling allocator. This also removes the need for `MAP_NORESERVE` in the
  uffd implementation.
* Moar comments.
* Remove `BasePointerIterator` in favor of `impl Iterator`.
* The uffd implementation now only monitors linear memory pages and will only
  receive faults on pages that could potentially be accessible and never on a
  statically known guard page.
* Stop allocating memory or table pools if the maximum limit of the memory or
  table is 0.
This commit is contained in:
Peter Huene
2021-03-04 14:01:42 -08:00
parent a464465e2f
commit ff840b3d3b
11 changed files with 484 additions and 500 deletions
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14
crates/runtime/src/instance.rs
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@@ -67,10 +67,10 @@ pub(crate) struct Instance {
/// Hosts can store arbitrary per-instance information here.
host_state: Box<dyn Any>,
/// Stores guard page faults in memory relating to the instance.
/// This is used for the pooling allocator with uffd enabled on Linux.
/// Stores linear memory guard page faults for the pooling allocator with uffd enabled.
/// These pages need to be reset after the signal handler generates the out-of-bounds trap.
#[cfg(all(feature = "uffd", target_os = "linux"))]
guard_page_faults: RefCell<Vec<(*mut u8, usize, unsafe fn(*mut u8, usize) -> bool)>>,
guard_page_faults: RefCell<Vec<(*mut u8, usize, fn(*mut u8, usize) -> anyhow::Result<()>)>>,
/// Additional context used by compiled wasm code. This field is last, and
/// represents a dynamically-sized array that extends beyond the nominal
@@ -821,7 +821,7 @@ impl Instance {
&self,
page_addr: *mut u8,
size: usize,
reset: unsafe fn(*mut u8, usize) -> bool,
reset: fn(*mut u8, usize) -> anyhow::Result<()>,
) {
self.guard_page_faults
.borrow_mut()
@@ -837,11 +837,7 @@ impl Instance {
pub(crate) fn reset_guard_pages(&self) -> anyhow::Result<()> {
let mut faults = self.guard_page_faults.borrow_mut();
for (addr, len, reset) in faults.drain(..) {
unsafe {
if !reset(addr, len) {
anyhow::bail!("failed to reset previously faulted memory guard page");
}
}
reset(addr, len)?;
}
Ok(())