Workaround to ensure proc kfmap does not try to map kernel memory

src/scheme/proc.rs

@@ -1258,13 +1258,31 @@ impl KernelScheme for ProcScheme {
 
         match info.operation {
             Operation::GrantHandle { ref description } => {
+                // Copy Map to user memory
+                let page_count = 1; // TODO: find size required to store Map
+                let page = dst_addr_space
+                    .write()
+                    .mmap(None, page_count, MapFlags::PROT_READ, |page, flags, mapper, flusher| {
+                        Ok(Grant::zeroed(page, page_count, flags, mapper, flusher)?)
+                    })?;
+                
+                // Write Map using kernel's physmap
+                let (phys, _flags) = dst_addr_space.read().table.utable.translate(page.start_address()).expect("could not find mapping that was just made");
+                unsafe { core::ptr::write(RmmA::phys_to_virt(phys).data() as *mut Map, *map); }
+
+                // Scheme fmap with Map in user memory
                 let (scheme_id, number) = {
                     let description = description.read();
 
                     (description.scheme, description.number)
                 };
                 let scheme = Arc::clone(scheme::schemes().get(scheme_id).ok_or(Error::new(EBADFD))?);
-                scheme.fmap(number, map)
+                let res = scheme.fmap(number, unsafe { &*(page.start_address().data() as *const Map) });
+
+                // Unmap Map user memory
+                dst_addr_space.write().munmap(page, page_count);
+
+                res
             }
             Operation::AddrSpace { ref addrspace } => {
                 if Arc::ptr_eq(addrspace, dst_addr_space) {