vmm: config: Move TDX to rely on PayloadConfig

Removing the option --tdx to specify that we want to run a TD VM. Rely
on --platform option by adding the "tdx" boolean parameter. This is the
new way for enabling TDX with Cloud Hypervisor.

Along with this change, the way to retrieve the firmware path has been
updated to rely on the recently introduced PayloadConfig structure.

Fixes #4556

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

vmm/src/config.rs

@@ -153,6 +153,9 @@ pub enum ValidationError {
     /// CPU Hotplug is not permitted with TDX
     #[cfg(feature = "tdx")]
     TdxNoCpuHotplug,
+    /// Missing firmware for TDX
+    #[cfg(feature = "tdx")]
+    TdxFirmwareMissing,
     /// Insuffient vCPUs for queues
     TooManyQueues,
     /// Need shared memory for vfio-user
@@ -219,6 +222,10 @@ impl fmt::Display for ValidationError {
             TdxNoCpuHotplug => {
                 write!(f, "CPU hotplug is not permitted with TDX")
             }
+            #[cfg(feature = "tdx")]
+            TdxFirmwareMissing => {
+                write!(f, "No TDX firmware specified")
+            }
             TooManyQueues => {
                 write!(f, "Number of vCPUs is insufficient for number of queues")
             }
@@ -363,8 +370,6 @@ pub struct VmParams<'a> {
     pub sgx_epc: Option<Vec<&'a str>>,
     pub numa: Option<Vec<&'a str>>,
     pub watchdog: bool,
-    #[cfg(feature = "tdx")]
-    pub tdx: Option<&'a str>,
     #[cfg(feature = "gdb")]
     pub gdb: bool,
     pub platform: Option<&'a str>,
@@ -397,8 +402,6 @@ impl<'a> VmParams<'a> {
         let numa: Option<Vec<&str>> = args.values_of("numa").map(|x| x.collect());
         let watchdog = args.is_present("watchdog");
         let platform = args.value_of("platform");
-        #[cfg(feature = "tdx")]
-        let tdx = args.value_of("tdx");
         #[cfg(feature = "gdb")]
         let gdb = args.is_present("gdb");
         VmParams {
@@ -425,8 +428,6 @@ impl<'a> VmParams<'a> {
             sgx_epc,
             numa,
             watchdog,
-            #[cfg(feature = "tdx")]
-            tdx,
             #[cfg(feature = "gdb")]
             gdb,
             platform,
@@ -642,16 +643,22 @@ pub struct PlatformConfig {
     pub uuid: Option<String>,
     #[serde(default)]
     pub oem_strings: Option<Vec<String>>,
+    #[cfg(feature = "tdx")]
+    #[serde(default)]
+    pub tdx: bool,
 }
 
 impl PlatformConfig {
     pub fn parse(platform: &str) -> Result<Self> {
         let mut parser = OptionParser::new();
-        parser.add("num_pci_segments");
-        parser.add("iommu_segments");
-        parser.add("serial_number");
-        parser.add("uuid");
-        parser.add("oem_strings");
+        parser
+            .add("num_pci_segments")
+            .add("iommu_segments")
+            .add("serial_number")
+            .add("uuid")
+            .add("oem_strings");
+        #[cfg(feature = "tdx")]
+        parser.add("tdx");
         parser.parse(platform).map_err(Error::ParsePlatform)?;
 
         let num_pci_segments: u16 = parser
@@ -670,12 +677,20 @@ impl PlatformConfig {
             .convert::<StringList>("oem_strings")
             .map_err(Error::ParsePlatform)?
             .map(|v| v.0);
+        #[cfg(feature = "tdx")]
+        let tdx = parser
+            .convert::<Toggle>("tdx")
+            .map_err(Error::ParsePlatform)?
+            .unwrap_or(Toggle(false))
+            .0;
         Ok(PlatformConfig {
             num_pci_segments,
             iommu_segments,
             serial_number,
             uuid,
             oem_strings,
+            #[cfg(feature = "tdx")]
+            tdx,
         })
     }
 
@@ -706,6 +721,8 @@ impl Default for PlatformConfig {
             serial_number: None,
             uuid: None,
             oem_strings: None,
+            #[cfg(feature = "tdx")]
+            tdx: false,
         }
     }
 }
@@ -2083,26 +2100,6 @@ impl VsockConfig {
     }
 }
 
-#[cfg(feature = "tdx")]
-#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize, Default)]
-pub struct TdxConfig {
-    pub firmware: PathBuf,
-}
-
-#[cfg(feature = "tdx")]
-impl TdxConfig {
-    pub fn parse(tdx: &str) -> Result<Self> {
-        let mut parser = OptionParser::new();
-        parser.add("firmware");
-        parser.parse(tdx).map_err(Error::ParseTdx)?;
-        let firmware = parser
-            .get("firmware")
-            .map(PathBuf::from)
-            .ok_or(Error::FirmwarePathMissing)?;
-        Ok(TdxConfig { firmware })
-    }
-}
-
 #[cfg(target_arch = "x86_64")]
 #[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize, Default)]
 pub struct SgxEpcConfig {
@@ -2296,8 +2293,6 @@ pub struct VmConfig {
     pub numa: Option<Vec<NumaConfig>>,
     #[serde(default)]
     pub watchdog: bool,
-    #[cfg(feature = "tdx")]
-    pub tdx: Option<TdxConfig>,
     #[cfg(feature = "gdb")]
     pub gdb: bool,
     pub platform: Option<PlatformConfig>,
@@ -2341,16 +2336,16 @@ impl VmConfig {
             })
         }
 
-        #[cfg(not(feature = "tdx"))]
         self.payload
             .as_ref()
             .ok_or(ValidationError::KernelMissing)?;
 
         #[cfg(feature = "tdx")]
         {
-            let tdx_enabled = self.tdx.is_some();
-            if !tdx_enabled && self.payload.is_none() {
-                return Err(ValidationError::KernelMissing);
+            let tdx_enabled = self.platform.as_ref().map(|p| p.tdx).unwrap_or(false);
+            // At this point we know payload isn't None.
+            if tdx_enabled && self.payload.as_ref().unwrap().firmware.is_none() {
+                return Err(ValidationError::TdxFirmwareMissing);
             }
             if tdx_enabled && (self.cpus.max_vcpus != self.cpus.boot_vcpus) {
                 return Err(ValidationError::TdxNoCpuHotplug);
@@ -2686,9 +2681,6 @@ impl VmConfig {
             None
         };
 
-        #[cfg(feature = "tdx")]
-        let tdx = vm_params.tdx.map(TdxConfig::parse).transpose()?;
-
         #[cfg(feature = "gdb")]
         let gdb = vm_params.gdb;
 
@@ -2716,8 +2708,6 @@ impl VmConfig {
             sgx_epc,
             numa,
             watchdog: vm_params.watchdog,
-            #[cfg(feature = "tdx")]
-            tdx,
             #[cfg(feature = "gdb")]
             gdb,
             platform,
@@ -2725,6 +2715,11 @@ impl VmConfig {
         config.validate().map_err(Error::Validation)?;
         Ok(config)
     }
+
+    #[cfg(feature = "tdx")]
+    pub fn is_tdx_enabled(&self) -> bool {
+        self.platform.as_ref().map(|p| p.tdx).unwrap_or(false)
+    }
 }
 
 #[cfg(test)]
@@ -3323,8 +3318,6 @@ mod tests {
             sgx_epc: None,
             numa: None,
             watchdog: false,
-            #[cfg(feature = "tdx")]
-            tdx: None,
             #[cfg(feature = "gdb")]
             gdb: false,
             platform: None,