From d57c9964851020dc431761d88bc955ac96ff7de1 Mon Sep 17 00:00:00 2001
From: Oliver Anderson <oliver.anderson@cyberus-technology.de>
Date: Wed, 17 Jun 2026 13:52:12 +0200
Subject: [PATCH] vmm: Set vCPU MSR config updates when creating vCPUs

Vcpus need to be configured according to the selected CPU profile.
We thus store the computed vCPU MSR config update in the CPU manager
and use it whenever a vCPU is created.

Signed-off-by: Oliver Anderson <oliver.anderson@cyberus-technology.de>
On-behalf-of: SAP oliver.anderson@sap.com
---
 vmm/src/cpu.rs | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/vmm/src/cpu.rs b/vmm/src/cpu.rs
index 21301e9fe..5d9499878 100644
--- a/vmm/src/cpu.rs
+++ b/vmm/src/cpu.rs
@@ -234,6 +234,9 @@ pub enum Error {
 
     #[error("Error enabling core scheduling")]
     CoreScheduling(#[source] io::Error),
+
+    #[error("Error generating MSR configuration update")]
+    MsrConfigurationUpdate(#[source] arch::Error),
 }
 pub type Result<T> = result::Result<T, Error>;
 
@@ -709,6 +712,8 @@ pub struct CpuManager {
     interrupt_controller: Option<Arc<Mutex<dyn InterruptController>>>,
     #[cfg(target_arch = "x86_64")]
     cpuid: Vec<CpuIdEntry>,
+    #[cfg(target_arch = "x86_64")]
+    msr_config_update: Option<VcpuMsrConfigUpdate>,
     #[cfg_attr(target_arch = "aarch64", allow(dead_code))]
     vm: Arc<dyn hypervisor::Vm>,
     vcpus_kill_signalled: Arc<AtomicBool>,
@@ -932,11 +937,22 @@ impl CpuManager {
             .map_err(Error::CommonCpuId)?
         };
 
+        #[cfg(target_arch = "x86_64")]
+        let msr_config_update = arch::x86_64::generate_required_msr_updates(
+            hypervisor.as_ref(),
+            config.profile,
+            config.kvm_hyperv,
+            config.nested,
+        )
+        .map_err(Error::MsrConfigurationUpdate)?;
+
         Ok(Arc::new(Mutex::new(CpuManager {
             config: config.clone(),
             interrupt_controller: None,
             #[cfg(target_arch = "x86_64")]
             cpuid,
+            #[cfg(target_arch = "x86_64")]
+            msr_config_update,
             vm,
             vcpus_kill_signalled: Arc::new(AtomicBool::new(false)),
             vcpus_pause_signalled: Arc::new(AtomicBool::new(false)),
@@ -986,7 +1002,7 @@ impl CpuManager {
             #[cfg(target_arch = "x86_64")]
             self.hypervisor.get_cpu_vendor(),
             #[cfg(target_arch = "x86_64")]
-            Default::default(),
+            self.msr_config_update.clone(),
         )?;
 
         if let Some(snapshot) = snapshot {