diff --git a/vmbase/src/lib.rs b/vmbase/src/lib.rs
index d086f1c..2541b8a 100644
--- a/vmbase/src/lib.rs
+++ b/vmbase/src/lib.rs
@@ -16,6 +16,8 @@
 
 #![no_std]
 
+extern crate alloc;
+
 pub mod arch;
 mod bionic;
 pub mod console;
diff --git a/vmbase/src/memory/mod.rs b/vmbase/src/memory/mod.rs
index 149fd18..5e1065a 100644
--- a/vmbase/src/memory/mod.rs
+++ b/vmbase/src/memory/mod.rs
@@ -16,6 +16,10 @@
 
 mod dbm;
 mod page_table;
+mod shared;
+mod util;
 
 pub use dbm::set_dbm_enabled;
 pub use page_table::{PageTable, MMIO_LAZY_MAP_FLAG};
+pub use shared::MemorySharer;
+pub use util::{phys_to_virt, virt_to_phys};
diff --git a/vmbase/src/memory/shared.rs b/vmbase/src/memory/shared.rs
new file mode 100644
index 0000000..0a2444f
--- /dev/null
+++ b/vmbase/src/memory/shared.rs
@@ -0,0 +1,78 @@
+// Copyright 2023, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Shared memory management.
+
+use super::util::virt_to_phys;
+use alloc::alloc::{alloc_zeroed, dealloc, handle_alloc_error};
+use alloc::vec::Vec;
+use buddy_system_allocator::FrameAllocator;
+use core::alloc::Layout;
+use core::ptr::NonNull;
+use hyp::get_hypervisor;
+use log::trace;
+
+/// Allocates memory on the heap and shares it with the host.
+///
+/// Unshares all pages when dropped.
+pub struct MemorySharer {
+    granule: usize,
+    shared_regions: Vec<(usize, Layout)>,
+}
+
+impl MemorySharer {
+    /// Constructs a new `MemorySharer` instance with the specified granule size and capacity.
+    /// `granule` must be a power of 2.
+    pub fn new(granule: usize, capacity: usize) -> Self {
+        assert!(granule.is_power_of_two());
+        Self { granule, shared_regions: Vec::with_capacity(capacity) }
+    }
+
+    /// Get from the global allocator a granule-aligned region that suits `hint` and share it.
+    pub fn refill(&mut self, pool: &mut FrameAllocator<32>, hint: Layout) {
+        let layout = hint.align_to(self.granule).unwrap().pad_to_align();
+        assert_ne!(layout.size(), 0);
+        // SAFETY - layout has non-zero size.
+        let Some(shared) = NonNull::new(unsafe { alloc_zeroed(layout) }) else {
+            handle_alloc_error(layout);
+        };
+
+        let base = shared.as_ptr() as usize;
+        let end = base.checked_add(layout.size()).unwrap();
+        trace!("Sharing memory region {:#x?}", base..end);
+        for vaddr in (base..end).step_by(self.granule) {
+            let vaddr = NonNull::new(vaddr as *mut _).unwrap();
+            get_hypervisor().mem_share(virt_to_phys(vaddr).try_into().unwrap()).unwrap();
+        }
+        self.shared_regions.push((base, layout));
+
+        pool.add_frame(base, end);
+    }
+}
+
+impl Drop for MemorySharer {
+    fn drop(&mut self) {
+        while let Some((base, layout)) = self.shared_regions.pop() {
+            let end = base.checked_add(layout.size()).unwrap();
+            trace!("Unsharing memory region {:#x?}", base..end);
+            for vaddr in (base..end).step_by(self.granule) {
+                let vaddr = NonNull::new(vaddr as *mut _).unwrap();
+                get_hypervisor().mem_unshare(virt_to_phys(vaddr).try_into().unwrap()).unwrap();
+            }
+
+            // SAFETY - The region was obtained from alloc_zeroed() with the recorded layout.
+            unsafe { dealloc(base as *mut _, layout) };
+        }
+    }
+}
diff --git a/vmbase/src/memory/util.rs b/vmbase/src/memory/util.rs
new file mode 100644
index 0000000..5b89cd1
--- /dev/null
+++ b/vmbase/src/memory/util.rs
@@ -0,0 +1,33 @@
+// Copyright 2023, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Utility functions for memory management.
+
+use core::ptr::NonNull;
+
+/// Returns the intermediate physical address corresponding to the given virtual address.
+///
+/// As we use identity mapping for everything, this is just a cast, but it's useful to use it to be
+/// explicit about where we are converting from virtual to physical address.
+pub fn virt_to_phys(vaddr: NonNull<u8>) -> usize {
+    vaddr.as_ptr() as _
+}
+
+/// Returns a pointer for the virtual address corresponding to the given non-zero intermediate
+/// physical address.
+///
+/// Panics if `paddr` is 0.
+pub fn phys_to_virt(paddr: usize) -> NonNull<u8> {
+    NonNull::new(paddr as _).unwrap()
+}