vmm: plumb legacy SMBIOS config

Add a small SMBIOS config that carries serial_number, uuid,
and OEM strings, and pass it from platform config into
x86_64 setup.

On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>

vmm/src/vm_config.rs

@@ -149,6 +149,21 @@ pub struct PlatformConfig {
     pub vfio_p2p_dma: bool,
 }
 
+#[cfg(target_arch = "x86_64")]
+impl PlatformConfig {
+    /// Returns `None` if no SMBIOS-relevant platform fields are set, otherwise
+    /// `Some` with a [`SmbiosConfig`] built from the populated fields.
+    pub fn smbios_config(&self) -> Option<arch::x86_64::SmbiosConfig> {
+        let smbios = arch::x86_64::SmbiosConfig {
+            serial_number: self.serial_number.clone(),
+            uuid: self.uuid.clone(),
+            oem_strings: self.oem_strings.clone().unwrap_or_default(),
+        };
+
+        (!smbios.is_empty()).then_some(smbios)
+    }
+}
+
 pub const DEFAULT_PCI_SEGMENT_APERTURE_WEIGHT: u32 = 1;
 
 fn default_pci_segment_aperture_weight() -> u32 {