From ad3790a0ea9d03a7c8f5a361f830eee1159dafb2 Mon Sep 17 00:00:00 2001
From: Pascal Scholz <pascal.scholz@cyberus-technology.de>
Date: Mon, 20 Jul 2026 14:28:57 +0200
Subject: [PATCH] vmm: Update memory zones

We consume `zone_updates` from `VmReceiveMigrationData` and
`RestoreConfig` to remap already existing `MemoryZone`s to different
host NUMA nodes. For now, we do not support further changes, such as
altering the size of the respective `MemoryZone`s.

These changes allow to migrate a VM to a host that has the capacity to
host the same `MemoryZone`s on a different NUMA layout.

Signed-off-by: Pascal Scholz <pascal.scholz@cyberus-technology.de>
On-behalf-of: SAP pascal.scholz@sap.com
---
 vmm/src/lib.rs | 10 ++++++++++
 vmm/src/vm.rs  |  6 +++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/vmm/src/lib.rs b/vmm/src/lib.rs
index d3feb182a..d6ff2ae24 100644
--- a/vmm/src/lib.rs
+++ b/vmm/src/lib.rs
@@ -1178,6 +1178,7 @@ impl Vmm {
         T: Read,
     {
         let mode = receive_data_migration.memory_mode;
+        let zone_updates = &receive_data_migration.zone_updates;
 
         // Read in config data along with memory manager data
         let mut data: Vec<u8> = Vec::new();
@@ -1222,6 +1223,10 @@ impl Vmm {
             &vm_migration_config.common_cpuid,
         )?;
 
+        update_memory_zones(zone_updates, &vm_migration_config.vm_config).map_err(|e| {
+            MigratableError::MigrateReceive(anyhow!("Error updating memory zones: {e:?}"))
+        })?;
+
         let config = vm_migration_config.vm_config.clone();
         self.vm_config = Some(vm_migration_config.vm_config);
         self.console_info = Some(
@@ -2518,6 +2523,11 @@ impl RequestHandler for Vmm {
                         .iommufd_fd = Some(iommufd_fd);
                 }
 
+                update_memory_zones(&restore_cfg.zone_updates, &vm_config).map_err(|e| {
+                    error!("VM Restore failed: {e:?}");
+                    VmError::ApplyMemoryZoneUpdate(e)
+                })?;
+
                 self.vm_restore(
                     source_url,
                     vm_config,
diff --git a/vmm/src/vm.rs b/vmm/src/vm.rs
index 281066308..14e934f41 100644
--- a/vmm/src/vm.rs
+++ b/vmm/src/vm.rs
@@ -120,7 +120,7 @@ use crate::vm_config::{
 };
 use crate::{
     CPU_MANAGER_SNAPSHOT_ID, DEVICE_MANAGER_SNAPSHOT_ID, GuestMemoryMmap,
-    MEMORY_MANAGER_SNAPSHOT_ID, PciDeviceInfo, acpi, cpu,
+    MEMORY_MANAGER_SNAPSHOT_ID, MemoryZoneUpdateError, PciDeviceInfo, acpi, cpu,
 };
 
 /// Errors associated with VM management
@@ -399,6 +399,10 @@ pub enum Error {
     #[cfg(feature = "fw_cfg")]
     #[error("Error using fw_cfg while disabled")]
     FwCfgDisabled,
+
+    /// Cannot apply NUMA memory zone updates
+    #[error("Error applying memory zone updates")]
+    ApplyMemoryZoneUpdate(#[source] MemoryZoneUpdateError),
 }
 pub type Result<T> = result::Result<T, Error>;