mm/vm: minor cleanups #183
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Use a strongly typed page size in the memory mapping interfaces Signed-off-by: Carlos López <carlos.lopez@suse.com>
Signed-off-by: Carlos López <carlos.lopez@suse.com>
Clean up control flow in VMR::handle_page_fault() to reduce indentation and make code easier to read. Signed-off-by: Carlos López <carlos.lopez@suse.com>
Signed-off-by: Carlos López <carlos.lopez@suse.com>
Clean up control flow in VMFileMapping::handle_page_fault() to reduce indentation and make code easier to read. Signed-off-by: Carlos López <carlos.lopez@suse.com>
src/mm/vm/mapping/file_mapping.rs
Outdated
| if write { | ||
| if let Some(write_copy) = self.write_copy.as_mut() { | ||
| // This is a writeable region with copy-on-write access. The | ||
| // page fault will have occurred because the page has not yet | ||
| // been allocated. Allocate a page and copy the readonly source | ||
| // page into the new writeable page. | ||
| let offset_aligned = offset & !(page_size - 1); | ||
| let offset_aligned = offset & !(page_size_bytes - 1); |
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What about adding PageSize::mask()?
I mean something like this:
diff --git a/src/mm/vm/mapping/file_mapping.rs b/src/mm/vm/mapping/file_mapping.rs
index 51540aa..a687442 100644
--- a/src/mm/vm/mapping/file_mapping.rs
+++ b/src/mm/vm/mapping/file_mapping.rs
@@ -222,7 +222,6 @@ impl VirtualMapping for VMFileMapping {
write: bool,
) -> Result<VMPageFaultResolution, SvsmError> {
let page_size = self.page_size();
- let page_size_bytes = usize::from(page_size);
if !write {
return Err(SvsmError::Mem);
@@ -236,7 +235,7 @@ impl VirtualMapping for VMFileMapping {
// page fault will have occurred because the page has not yet
// been allocated. Allocate a page and copy the readonly source
// page into the new writeable page.
- let offset_aligned = offset & !(page_size_bytes - 1);
+ let offset_aligned = offset & page_size.mask();
write_copy.get_alloc_mut().alloc_page(offset_aligned)?;
let paddr_new_page = write_copy.map(offset_aligned).ok_or(SvsmError::Mem)?;
copy_page(vmr, &self.file, offset_aligned, paddr_new_page, page_size)?;
diff --git a/src/types.rs b/src/types.rs
index 770b213..f805cb9 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -17,6 +17,12 @@ pub enum PageSize {
Huge,
}
+impl PageSize {
+ pub fn mask(self) -> usize {
+ !(usize::from(self) - 1)
+ }
+}
+
impl From<PageSize> for usize {
fn from(psize: PageSize) -> Self {
match psize {We can do also in another PR if you prefer to keep this simple.
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Probably best left for a separate PR :)
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Minor cleanup and readability changes.