fix(vmm): Save/restore IA32_ARCH_CAPABILITIES MSR into/from a snapshot

The MSR reports available hardware mitigations. The mitigations to apply
should be already selected at boot time and should not change after
snapshot restore, but there is no reason to not save/restore the value.

Signed-off-by: Takahiro Itazuri <[email protected]>

Author: zulinx86

CHANGELOG.md

@@ -52,6 +52,9 @@ and this project adheres to
   the UFFD Unix domain socket open to prevent the race condition between the
   guest memory mappings message and the shutdown event that was sometimes
   causing arrival of an empty message on the UFFD handler side.
+- [#5142](https://github.com/firecracker-microvm/firecracker/pull/5142): Fixed
+  to save/restore IA32_ARCH_CAPABILITIES MSR (index: 0x10a) into/from a
+  snapshot.
 
 ## [1.11.0]
 

src/vmm/src/arch/x86_64/msr.rs

@@ -237,6 +237,7 @@ static SERIALIZABLE_MSR_RANGES: &[MsrRange] = &[
     MSR_RANGE!(MSR_KVM_POLL_CONTROL),
     MSR_RANGE!(MSR_KVM_ASYNC_PF_INT),
     MSR_RANGE!(MSR_IA32_TSX_CTRL),
+    MSR_RANGE!(MSR_IA32_ARCH_CAPABILITIES),
 ];
 
 /// Specifies whether a particular MSR should be included in vcpu serialization.