rust/pv: Provide default for UvCmd::cmd

Provides a default for the cmd function for an UvCmd. This is enabled by
requiring an associated constant for the IOCTL nr of the command.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Julian Ruess <julianr@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

rust/pv_core/src/uvdevice.rs

@@ -83,15 +83,20 @@ fn rc_fmt<C: UvCmd>(rc: u16, rrc: u16, cmd: &mut C) -> &'static str {
 
 /// Ultravisor Command.
 pub trait UvCmd {
+    /// The UV IOCTL number of the UV call
+    const UV_IOCTL_NR: u8;
     /// Returns the uvdevice IOCTL command that his command uses.
     ///
     /// # Returns
     /// The IOCTL cmd for this UvCmd usually sth like `uv_ioctl!(CMD_NR)`
-    fn cmd(&self) -> u64;
+    fn cmd(&self) -> u64 {
+        uv_ioctl(Self::UV_IOCTL_NR)
+    }
     /// Converts UV return codes into human readable error messages
     ///
     /// no need to handle `0x0000, 0x0001, 0x0002, 0x0005, 0x0030, 0x0031, 0x0032, 0x0100`
     fn rc_fmt(&self, rc: u16, rrc: u16) -> Option<&'static str>;
+
     /// Returns data used by this command if available.
     fn data(&mut self) -> Option<&mut [u8]> {
         None

rust/pv_core/src/uvdevice/info.rs

@@ -72,9 +72,7 @@ impl From<uvio_uvdev_info> for UvDeviceInfo {
 }
 
 impl UvCmd for uvio_uvdev_info {
-    fn cmd(&self) -> u64 {
-        uv_ioctl(UvDevice::INFO_NR)
-    }
+    const UV_IOCTL_NR: u8 = UvDevice::INFO_NR;
 
     fn data(&mut self) -> Option<&mut [u8]> {
         Some(self.as_bytes_mut())

rust/pv_core/src/uvdevice/secret.rs

@@ -42,14 +42,12 @@ impl Default for ListCmd {
 }
 
 impl UvCmd for ListCmd {
+    const UV_IOCTL_NR: u8 = UvDevice::LIST_SECRET_NR;
+
     fn data(&mut self) -> Option<&mut [u8]> {
         Some(self.0.as_mut_slice())
     }
 
-    fn cmd(&self) -> u64 {
-        uv_ioctl(UvDevice::LIST_SECRET_NR)
-    }
-
     fn rc_fmt(&self, _rc: u16, _rrc: u16) -> Option<&'static str> {
         None
     }
@@ -80,14 +78,12 @@ impl AddCmd {
 }
 
 impl UvCmd for AddCmd {
+    const UV_IOCTL_NR: u8 = UvDevice::ADD_SECRET_NR;
+
     fn data(&mut self) -> Option<&mut [u8]> {
         Some(&mut self.0)
     }
 
-    fn cmd(&self) -> u64 {
-        uv_ioctl(UvDevice::ADD_SECRET_NR)
-    }
-
     fn rc_fmt(&self, rc: u16, _rrc: u16) -> Option<&'static str> {
         match rc {
             0x0101 => Some("not allowed to modify the secret store"),
@@ -116,9 +112,7 @@ impl UvCmd for AddCmd {
 /// request to modify the secret store will fail.
 pub struct LockCmd;
 impl UvCmd for LockCmd {
-    fn cmd(&self) -> u64 {
-        uv_ioctl(UvDevice::LOCK_SECRET_NR)
-    }
+    const UV_IOCTL_NR: u8 = UvDevice::LOCK_SECRET_NR;
 
     fn rc_fmt(&self, rc: u16, _rrc: u16) -> Option<&'static str> {
         match rc {

rust/pv_core/src/uvdevice/test.rs

@@ -107,6 +107,8 @@ impl ffi::uvio_ioctl_cb {
 const TEST_CMD: u64 = 17;
 struct TestCmd(Option<Vec<u8>>);
 impl UvCmd for TestCmd {
+    const UV_IOCTL_NR: u8 = 42;
+
     fn cmd(&self) -> u64 {
         TEST_CMD
     }