Deduplicate code for transferring/creating grants.
This commit is contained in:
4lDO2
@@ -746,77 +746,66 @@ impl Scheme for ProcScheme {
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let mut addrspace = addrspace.write();
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let is_active = addrspace.is_current();
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let callback = |addr_space: &mut AddrSpace| {
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let (mut inactive, mut active);
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let (mut inactive, mut active);
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let (mut mapper, mut flusher) = if is_active {
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active = (unsafe { ActivePageTable::new(rmm::TableKind::User) }, PageFlushAll::new());
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(active.0.mapper(), &mut active.1 as &mut dyn Flusher<RmmA>)
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} else {
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inactive = (unsafe { InactivePageTable::from_address(addr_space.frame.utable.start_address().data()) }, InactiveFlusher::new());
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(inactive.0.mapper(), &mut inactive.1 as &mut dyn Flusher<RmmA>)
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};
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if let Some(src_address) = src_address {
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// Forbid transferring grants to the same address space!
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if is_active { return Err(Error::new(EBUSY)); }
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let src_grant = current_addrspace()?.write().grants.take(&Region::new(VirtualAddress::new(src_address), size)).ok_or(Error::new(EINVAL))?;
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if src_address % PAGE_SIZE != 0 || src_address.saturating_add(size) > crate::USER_END_OFFSET {
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return Err(Error::new(EINVAL));
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}
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// TODO: Allow downgrading flags?
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if let Some(grant) = addr_space.grants.conflicts(Region::new(VirtualAddress::new(base), size)).next() {
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return Err(Error::new(EEXIST));
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}
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addr_space.grants.insert(Grant::transfer(
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src_grant,
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Page::containing_address(VirtualAddress::new(base)),
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&mut *unsafe { ActivePageTable::new(rmm::TableKind::User) },
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&mut mapper,
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PageFlushAll::new(),
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flusher,
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));
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return Ok(());
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}
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let region = Region::new(VirtualAddress::new(base), size);
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let conflicting = addr_space.grants.conflicts(region).map(|g| *g.region()).collect::<Vec<_>>();
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for conflicting_region in conflicting {
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let whole_grant = addr_space.grants.take(&conflicting_region).ok_or(Error::new(EBADFD))?;
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let (before_opt, current, after_opt) = whole_grant.extract(region.intersect(conflicting_region)).ok_or(Error::new(EBADFD))?;
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if let Some(before) = before_opt {
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addr_space.grants.insert(before);
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}
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if let Some(after) = after_opt {
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addr_space.grants.insert(after);
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}
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let res = current.unmap(&mut mapper, &mut flusher);
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if res.file_desc.is_some() {
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return Err(Error::new(EBUSY));
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}
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// TODO: Partial free if grant is mapped externally, or fail and force
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// userspace to do it.
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}
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if flags.intersects(MapFlags::PROT_READ | MapFlags::PROT_EXEC | MapFlags::PROT_WRITE) {
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let base = Page::containing_address(VirtualAddress::new(base));
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addr_space.grants.insert(Grant::zeroed(base, size / PAGE_SIZE, page_flags(flags), &mut mapper, flusher)?);
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}
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Ok(())
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let (mut mapper, mut flusher) = if is_active {
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active = (unsafe { ActivePageTable::new(rmm::TableKind::User) }, PageFlushAll::new());
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(active.0.mapper(), &mut active.1 as &mut dyn Flusher<RmmA>)
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} else {
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inactive = (unsafe { InactivePageTable::from_address(addrspace.frame.utable.start_address().data()) }, InactiveFlusher::new());
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(inactive.0.mapper(), &mut inactive.1 as &mut dyn Flusher<RmmA>)
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};
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callback(&mut *addrspace)?;
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// TODO: Set some "in use" flag every time an address space is switched to. This
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let region = Region::new(VirtualAddress::new(base), size);
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let conflicting = addrspace.grants.conflicts(region).map(|g| *g.region()).collect::<Vec<_>>();
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for conflicting_region in conflicting {
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let whole_grant = addrspace.grants.take(&conflicting_region).ok_or(Error::new(EBADFD))?;
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let (before_opt, current, after_opt) = whole_grant.extract(region.intersect(conflicting_region)).ok_or(Error::new(EBADFD))?;
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if let Some(before) = before_opt {
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addrspace.grants.insert(before);
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}
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if let Some(after) = after_opt {
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addrspace.grants.insert(after);
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}
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let res = current.unmap(&mut mapper, &mut flusher);
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if res.file_desc.is_some() {
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// We prefer avoiding file operations from within the kernel. If userspace
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// updates grants that overlap, it might as well enumerate grants and call
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// partial funmap on its own.
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return Err(Error::new(EBUSY));
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}
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}
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let base_page = Page::containing_address(VirtualAddress::new(base));
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if let Some(src_address) = src_address {
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// Forbid transferring grants to the same address space!
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if is_active { return Err(Error::new(EBUSY)); }
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let src_grant = current_addrspace()?.write().grants.take(&Region::new(VirtualAddress::new(src_address), size)).ok_or(Error::new(EINVAL))?;
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if src_address % PAGE_SIZE != 0 || src_address.saturating_add(size) > crate::USER_END_OFFSET {
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return Err(Error::new(EINVAL));
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}
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// TODO: Allow downgrading flags?
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addrspace.grants.insert(Grant::transfer(
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src_grant,
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base_page,
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&mut *unsafe { ActivePageTable::new(rmm::TableKind::User) },
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&mut mapper,
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PageFlushAll::new(),
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flusher,
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));
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} else if flags.intersects(MapFlags::PROT_READ | MapFlags::PROT_EXEC | MapFlags::PROT_WRITE) {
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addrspace.grants.insert(Grant::zeroed(base_page, size / PAGE_SIZE, page_flags(flags), &mut mapper, flusher)?);
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}
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// TODO: Set some "in use" flag every time an address space is switched to? This
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// way, we know what hardware threads are using any given page table, which we need
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// to know while doing TLB shootdown.
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