vmm: Introduce new CPU option to set maximum physical bits

In order to let the user choose maximum address space size, this patch
introduces a new option `max_phys_bits` to the `--cpus` parameter.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/api/openapi/cloud-hypervisor.yaml

@@ -469,6 +469,8 @@ components:
           type: integer
         topology:
             $ref: '#/components/schemas/CpuTopology'
+        max_phys_bits:
+          type: integer
 
     MemoryZoneConfig:
       required:

vmm/src/config.rs

@@ -320,6 +320,8 @@ pub struct CpusConfig {
     pub topology: Option<CpuTopology>,
     #[serde(default)]
     pub kvm_hyperv: bool,
+    #[serde(default)]
+    pub max_phys_bits: Option<u8>,
 }
 
 impl CpusConfig {
@@ -329,7 +331,8 @@ impl CpusConfig {
             .add("boot")
             .add("max")
             .add("topology")
-            .add("kvm_hyperv");
+            .add("kvm_hyperv")
+            .add("max_phys_bits");
         parser.parse(cpus).map_err(Error::ParseCpus)?;
 
         let boot_vcpus: u8 = parser
@@ -346,12 +349,16 @@ impl CpusConfig {
             .map_err(Error::ParseCpus)?
             .unwrap_or(Toggle(false))
             .0;
+        let max_phys_bits = parser
+            .convert::<u8>("max_phys_bits")
+            .map_err(Error::ParseCpus)?;
 
         Ok(CpusConfig {
             boot_vcpus,
             max_vcpus,
             topology,
             kvm_hyperv,
+            max_phys_bits,
         })
     }
 }
@@ -363,6 +370,7 @@ impl Default for CpusConfig {
             max_vcpus: DEFAULT_VCPUS,
             topology: None,
             kvm_hyperv: false,
+            max_phys_bits: None,
         }
     }
 }