feat(domain): add memory module with page pool, per-process tracking, and region table

crates/domain/src/memory/mod.rs

@@ -0,0 +1,95 @@
+use types::{
+    address::PhysicalAddress,
+    bounded::PageCount,
+    generation::Generation,
+    id::{ProcessId, RegionId},
+};
+
+pub mod page_pool;
+pub mod process_memory;
+
+#[cfg(test)]
+#[path = "tests.rs"]
+mod tests;
+
+const MAX_REGIONS: usize = 256;
+
+pub struct MemoryRegion {
+    id: RegionId,
+    owner: ProcessId,
+    base: PhysicalAddress,
+    size: PageCount,
+    generation: Generation,
+}
+
+impl MemoryRegion {
+    pub fn new(
+        id: RegionId,
+        owner: ProcessId,
+        base: PhysicalAddress,
+        size: PageCount,
+        generation: Generation,
+    ) -> Self {
+        Self {
+            id,
+            owner,
+            base,
+            size,
+            generation,
+        }
+    }
+
+    pub fn id(&self) -> RegionId {
+        self.id
+    }
+
+    pub fn owner(&self) -> ProcessId {
+        self.owner
+    }
+
+    pub fn base(&self) -> PhysicalAddress {
+        self.base
+    }
+
+    pub fn size(&self) -> PageCount {
+        self.size
+    }
+
+    pub fn generation(&self) -> &Generation {
+        &self.generation
+    }
+}
+
+pub struct RegionTable {
+    regions: [Option<MemoryRegion>; MAX_REGIONS],
+}
+
+impl RegionTable {
+    pub fn new() -> Self {
+        Self {
+            regions: [const { None }; MAX_REGIONS],
+        }
+    }
+
+    pub fn insert(&mut self, region: MemoryRegion) -> Option<RegionId> {
+        let idx = self.regions.iter().position(|s| s.is_none())?;
+        let id = RegionId::from_raw(idx as u16);
+        self.regions[idx] = Some(region);
+        Some(id)
+    }
+
+    pub fn get(&self, id: RegionId) -> Option<&MemoryRegion> {
+        self.regions.get(id.raw() as usize).and_then(|s| s.as_ref())
+    }
+
+    pub fn remove(&mut self, id: RegionId) -> Option<MemoryRegion> {
+        self.regions.get_mut(id.raw() as usize).and_then(|s| s.take())
+    }
+
+    pub fn regions_for_process(&self, process: ProcessId) -> impl Iterator<Item = &MemoryRegion> {
+        self.regions
+            .iter()
+            .filter_map(|s| s.as_ref())
+            .filter(move |r| r.owner() == process)
+    }
+}