vmm: Don't expose MemoryManager ACPI functionality unless required

When running non-dynamic or with virtio-mem for hotplug the ACPI
functionality should not be included on the DSDT nor does the
MemoryManager need to be placed on the MMIO bus.

Fixes: #3883

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/device_manager.rs

@@ -1132,16 +1132,17 @@ impl DeviceManager {
 
         #[cfg(feature = "acpi")]
         {
-            let memory_manager_acpi_address = self.memory_manager.lock().unwrap().acpi_address;
+            if let Some(acpi_address) = self.memory_manager.lock().unwrap().acpi_address() {
                 self.address_manager
                     .mmio_bus
                     .insert(
                         Arc::clone(&self.memory_manager) as Arc<Mutex<dyn BusDevice>>,
-                    memory_manager_acpi_address.0,
+                        acpi_address.0,
                         MEMORY_MANAGER_ACPI_SIZE as u64,
                     )
                     .map_err(DeviceManagerError::BusError)?;
             }
+        }
 
         #[cfg(target_arch = "x86_64")]
         self.add_legacy_devices(

vmm/src/memory_manager.rs

@@ -180,7 +180,7 @@ pub struct MemoryManager {
     guest_ram_mappings: Vec<GuestRamMapping>,
 
     #[cfg(feature = "acpi")]
-    pub acpi_address: GuestAddress,
+    pub acpi_address: Option<GuestAddress>,
 }
 
 #[derive(Debug)]
@@ -1024,18 +1024,26 @@ impl MemoryManager {
             .ok_or(Error::CreateSystemAllocator)?,
         ));
 
-        #[cfg(feature = "acpi")]
-        let acpi_address = allocator
-            .lock()
-            .unwrap()
-            .allocate_platform_mmio_addresses(None, MEMORY_MANAGER_ACPI_SIZE as u64, None)
-            .ok_or(Error::AllocateMmioAddress)?;
-
         #[cfg(not(feature = "tdx"))]
         let dynamic = true;
         #[cfg(feature = "tdx")]
         let dynamic = !tdx_enabled;
 
+        let hotplug_method = config.hotplug_method.clone();
+
+        #[cfg(feature = "acpi")]
+        let acpi_address = if dynamic && hotplug_method == HotplugMethod::Acpi {
+            Some(
+                allocator
+                    .lock()
+                    .unwrap()
+                    .allocate_platform_mmio_addresses(None, MEMORY_MANAGER_ACPI_SIZE as u64, None)
+                    .ok_or(Error::AllocateMmioAddress)?,
+            )
+        } else {
+            None
+        };
+
         // If running on SGX the start of device area and RAM area may diverge but
         // at this point they are next to each other.
         let end_of_ram_area = start_of_device_area.unchecked_sub(1);
@@ -1053,7 +1061,7 @@ impl MemoryManager {
             selected_slot,
             mergeable: config.mergeable,
             allocator,
-            hotplug_method: config.hotplug_method.clone(),
+            hotplug_method,
             boot_ram,
             current_ram,
             next_hotplug_slot,
@@ -1837,6 +1845,11 @@ impl MemoryManager {
         }
         memory_slot_fds
     }
+
+    #[cfg(feature = "acpi")]
+    pub fn acpi_address(&self) -> Option<GuestAddress> {
+        self.acpi_address
+    }
 }
 
 #[cfg(feature = "acpi")]
@@ -2070,6 +2083,7 @@ impl Aml for MemoryMethods {
 #[cfg(feature = "acpi")]
 impl Aml for MemoryManager {
     fn append_aml_bytes(&self, bytes: &mut Vec<u8>) {
+        if let Some(acpi_address) = self.acpi_address {
             // Memory Hotplug Controller
             aml::Device::new(
                 "_SB_.MHPC".into(),
@@ -2083,15 +2097,15 @@ impl Aml for MemoryManager {
                         &aml::ResourceTemplate::new(vec![&aml::AddressSpace::new_memory(
                             aml::AddressSpaceCachable::NotCacheable,
                             true,
-                        self.acpi_address.0 as u64,
+                            acpi_address.0 as u64,
-                        self.acpi_address.0 + MEMORY_MANAGER_ACPI_SIZE as u64 - 1,
+                            acpi_address.0 + MEMORY_MANAGER_ACPI_SIZE as u64 - 1,
                         )]),
                     ),
                     // OpRegion and Fields map MMIO range into individual field values
                     &aml::OpRegion::new(
                         "MHPR".into(),
                         aml::OpRegionSpace::SystemMemory,
-                    self.acpi_address.0 as usize,
+                        acpi_address.0 as usize,
                         MEMORY_MANAGER_ACPI_SIZE,
                     ),
                     &aml::Field::new(
@@ -2145,6 +2159,18 @@ impl Aml for MemoryManager {
                 ],
             )
             .append_aml_bytes(bytes);
+        } else {
+            aml::Device::new(
+                "_SB_.MHPC".into(),
+                vec![
+                    &aml::Name::new("_HID".into(), &aml::EisaName::new("PNP0A06")),
+                    &aml::Name::new("_UID".into(), &"Memory Hotplug Controller"),
+                    // Empty MSCN for GED
+                    &aml::Method::new("MSCN".into(), 0, true, vec![]),
+                ],
+            )
+            .append_aml_bytes(bytes);
+        }
 
         #[cfg(target_arch = "x86_64")]
         {