diff --git a/src/context/memory.rs b/src/context/memory.rs
index c3c5423e791e81ce1a352210c4f53fa751c38107..749bb7755f07148d72c0a0468be5f019f63af447 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -700,41 +700,52 @@ impl Grant {
})
}
- pub fn borrow_fmap(span: PageSpan, flags: PageFlags<RmmA>, file_ref: GrantFileRef, src: Option<BorrowedFmapSource<'_>>, mapper: &mut PageMapper, mut flusher: impl Flusher<RmmA>) -> Self {
+ pub fn borrow_fmap(span: PageSpan, new_flags: PageFlags<RmmA>, file_ref: GrantFileRef, src: Option<BorrowedFmapSource<'_>>, mapper: &mut PageMapper, mut flusher: impl Flusher<RmmA>) -> Result<Self> {
if let Some(mut src) = src {
+ // FIXME: Iterate over grants rather than pages, to allow for not-yet-lazily mapped
+ // pages.
for dst_page in span.pages() {
- let src_page = src.src_page.next_by(dst_page.offset_from(span.base));
+ let src_page = src.src_base.next_by(dst_page.offset_from(span.base));
- let (frame, _) = src.src_mapper.translate(src_page.start_address()).unwrap();
+ let (frame, is_cow) = match src.mode {
+ MmapMode::Shared(src_mapper) => {
+ // TODO: Error code for "scheme responded with unmapped page"?
+ let (frame, _) = src_mapper.translate(src_page.start_address()).ok_or(Error::new(EIO))?;
- if let Some(page_info) = get_page_info(Frame::containing_address(frame)) {
+ (Frame::containing_address(frame), false)
+ }
+ MmapMode::Cow(ref mut src_mapper) => unsafe {
+ let (_, frame, _) = src_mapper.remap_with(src_page.start_address(), |flags| flags.write(false)).ok_or(Error::new(EIO))?;
+
+ (Frame::containing_address(frame), true)
+ }
+ };
+
+ if let Some(page_info) = get_page_info(frame) {
page_info.add_ref(false);
}
unsafe {
- flusher.consume(mapper.map_phys(dst_page.start_address(), frame, flags).unwrap());
+ flusher.consume(mapper.map_phys(dst_page.start_address(), frame.start_address(), new_flags.write(!is_cow)).unwrap());
}
}
}
- Self {
+ Ok(Self {
base: span.base,
info: GrantInfo {
page_count: span.count,
mapped: true,
- flags,
+ flags: new_flags,
provider: Provider::FmapBorrowed { file_ref },
}
- }
+ })
}
- // TODO: Do not return Vec, return an iterator perhaps? Referencing the source address space?
-
/// Borrow all pages in the range `[src_base, src_base+page_count)` from `src_address_space`,
/// mapping them into `[dst_base, dst_base+page_count)`. The destination pages will lazily read
/// the page tables of the source pages, but once present in the destination address space,
/// pages that are unmaped or moved will not be made visible to the destination address space.
- // TODO: Return only one grant
pub fn borrow(
src_address_space_lock: Arc<RwLock<AddrSpace>>,
src_address_space: &AddrSpace,
@@ -890,17 +901,19 @@ impl Grant {
};
let frame = Frame::containing_address(phys);
- let is_cow_opt = match self.info.provider {
- Provider::Allocated { .. } => Some(true),
- Provider::External { .. } => Some(false),
- Provider::PhysBorrowed { .. } => None,
- Provider::FmapBorrowed { .. } => Some(false),
+ let (is_cow_opt, require_info) = match self.info.provider {
+ Provider::Allocated { .. } => (Some(true), true),
+ Provider::External { .. } => (Some(false), false),
+ Provider::PhysBorrowed { .. } => (None, false),
+ Provider::FmapBorrowed { .. } => (Some(false), false),
};
if let Some(is_cow) = is_cow_opt {
- get_page_info(frame)
- .expect("allocated frame did not have an associated PageInfo")
- .remove_ref(is_cow);
+ if let Some(info) = get_page_info(frame) {
+ info.remove_ref(is_cow);
+ } else {
+ assert!(!require_info, "allocated frame did not have an associated PageInfo");
+ }
}
@@ -1396,13 +1409,13 @@ fn correct_inner(addr_space_lock: Arc<RwLock<AddrSpace>>, faulting_page: Page, a
Ok((frame, flush))
}
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum MmapMode {
- Cow,
- Shared,
+#[derive(Debug)]
+pub enum MmapMode<'a> {
+ Cow(&'a mut PageMapper),
+ Shared(&'a PageMapper),
}
pub struct BorrowedFmapSource<'a> {
- pub src_page: Page,
- pub src_mapper: &'a PageMapper,
+ pub src_base: Page,
+ pub mode: MmapMode<'a>,
}
diff --git a/src/scheme/user.rs b/src/scheme/user.rs
index 627f8b2685485f416383d5683739d022e9810336..6214064c72a274900ba1c21a3b92c0bd702aeb6c 100644
--- a/src/scheme/user.rs
+++ b/src/scheme/user.rs
@@ -457,16 +457,13 @@ impl UserInner {
return Err(Error::new(EINVAL));
}
- let mode = if map.flags.contains(MapFlags::MAP_SHARED) {
- MmapMode::Shared
- } else {
- MmapMode::Cow
- };
-
let src_address_space = Arc::clone(
self.context.upgrade().ok_or(Error::new(ENODEV))?
.read().addr_space()?
);
+ if Arc::ptr_eq(&src_address_space, &dst_addr_space) {
+ return Err(Error::new(EBUSY));
+ }
let (pid, desc) = {
let context_lock = context::current()?;
@@ -511,29 +508,34 @@ impl UserInner {
return Err(Error::new(EIO));
}
};
+ let file_ref = GrantFileRef {
+ description: desc,
+ base_offset: map.offset,
+ };
- let dst_base = match mode {
- MmapMode::Cow => todo!("mmap CoW"),
- MmapMode::Shared => {
- let file_ref = GrantFileRef {
- description: desc,
- base_offset: map.offset,
- };
- let src_guard = src_address_space.read();
- let src = match base_page_opt {
- Some(base_addr) => Some(BorrowedFmapSource {
- src_page: Page::containing_address(VirtualAddress::new(base_addr)),
- src_mapper: &src_guard.table.utable,
- }),
- None => None,
- };
- let page_count_nz = NonZeroUsize::new(page_count).expect("already validated map.size != 0");
- dst_addr_space.write().mmap(dst_base, page_count_nz, map.flags, |dst_base, flags, mapper, flusher| {
- Ok(Grant::borrow_fmap(PageSpan::new(dst_base, page_count), page_flags(map.flags), file_ref, src, mapper, flusher))
- })?
- }
+ let src_read_guard;
+ let mut src_write_guard;
+
+ let src = match base_page_opt {
+ Some(base_addr) => Some(BorrowedFmapSource {
+ src_base: Page::containing_address(VirtualAddress::new(base_addr)),
+ mode: if map.flags.contains(MapFlags::MAP_SHARED) {
+ src_read_guard = src_address_space.read();
+ MmapMode::Shared(&src_read_guard.table.utable)
+ } else {
+ src_write_guard = src_address_space.write();
+ MmapMode::Cow(&mut src_write_guard.table.utable)
+ },
+
+ }),
+ None => None,
};
+ let page_count_nz = NonZeroUsize::new(page_count).expect("already validated map.size != 0");
+ let dst_base = dst_addr_space.write().mmap(dst_base, page_count_nz, map.flags, |dst_base, flags, mapper, flusher| {
+ Grant::borrow_fmap(PageSpan::new(dst_base, page_count), page_flags(map.flags), file_ref, src, mapper, flusher)
+ })?;
+
Ok(dst_base.start_address().data())
}
}