pv: from_se_image: Return SE header version in addition to tags

Return the Secure Execution header version in addition to tags. This
comes handy as soon as multiple Secure Execution header versions are
supported.

Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Timo Keller <tkeller@linux.ibm.com>
Signed-off-by: Marc Hartmayer <marc@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

rust/pv/src/brcb.rs

@@ -12,6 +12,13 @@ use zerocopy::{BigEndian, FromBytes, Immutable, IntoBytes, KnownLayout, U32, U64
 // (SE) boot request control block aka SE header
 use crate::{assert_size, request::MagicValue, static_assert, Error, Result, PAGESIZE};
 
+/// Version of the Secure Execution header
+#[derive(Debug, PartialEq)]
+pub enum SeHdrVersion {
+    /// Secure Execution header v1
+    One = 0x100,
+}
+
 /// Struct containing all SE-header tags.
 ///
 /// Contains:
@@ -205,7 +212,7 @@ impl BootHdrTags {
     ///
     /// This function will return an error if the header could not be found in
     /// `img` or is invalid.
-    pub fn from_se_image<R>(img: &mut R) -> Result<Self>
+    pub fn from_se_image<R>(img: &mut R) -> Result<(Self, SeHdrVersion)>
     where
         R: Read + Seek,
     {
@@ -232,10 +239,13 @@ impl BootHdrTags {
         };
 
         // Some sanity checks
-        if hdr_head.version.get() != 0x100 {
-            debug!("Unsupported hdr-version: {:0>4x}", hdr_head.version.get());
-            return Err(Error::InvBootHdr);
-        }
+        let hdr_version = match hdr_head.version.get() {
+            0x100 => SeHdrVersion::One,
+            _ => {
+                debug!("Unsupported hdr-version: {:0>4x}", hdr_head.version.get());
+                return Err(Error::InvBootHdr);
+            }
+        };
 
         // go to the Boot header tag
         img.seek(Current(
@@ -248,12 +258,15 @@ impl BootHdrTags {
         let mut tag = [0u8; BootHdrHead::TAG_SIZE];
         img.read_exact(tag.as_mut_slice())?;
 
-        Ok(Self {
-            pld: hdr_head.pld,
-            ald: hdr_head.ald,
-            tld: hdr_head.tld,
-            tag,
-        })
+        Ok((
+            Self {
+                pld: hdr_head.pld,
+                ald: hdr_head.ald,
+                tld: hdr_head.tld,
+                tag,
+            },
+            hdr_version,
+        ))
     }
 }
 
@@ -319,7 +332,7 @@ mod tests {
     fn from_se_image_hdr() {
         let bin_hdr = get_test_asset!("exp/secure_guest.hdr");
         let hdr_tags = BootHdrTags::from_se_image(&mut Cursor::new(*bin_hdr)).unwrap();
-        assert_eq!(hdr_tags, EXP_HDR);
+        assert_eq!(hdr_tags, (EXP_HDR, SeHdrVersion::One));
     }
 
     #[test]
@@ -355,18 +368,19 @@ mod tests {
         let bin_hdr = get_test_asset!("exp/secure_guest.hdr");
         img[0x12000..0x12280].copy_from_slice(bin_hdr);
         let hdr_tags = BootHdrTags::from_se_image(&mut Cursor::new(img)).unwrap();
-        assert_eq!(hdr_tags, EXP_HDR);
+        assert_eq!(hdr_tags, (EXP_HDR, SeHdrVersion::One));
     }
 
     #[test]
     fn tags_convert_u8() {
         let bin_hdr = get_test_asset!("exp/secure_guest.hdr");
         let hdr_tags = BootHdrTags::from_se_image(&mut Cursor::new(*bin_hdr)).unwrap();
-        let ser: &[u8] = hdr_tags.as_ref();
+        let ser: &[u8] = hdr_tags.0.as_ref();
         let mut ser = ser.to_vec();
 
         let der: BootHdrTags = ser.clone().try_into().unwrap();
-        assert_eq!(hdr_tags, der);
+        assert_eq!(hdr_tags.0, der);
+        assert_eq!(hdr_tags.1, SeHdrVersion::One);
 
         ser.pop();
         let der: Result<BootHdrTags> = ser.clone().try_into();
@@ -379,7 +393,7 @@ mod tests {
     }
 
     #[test]
-    fn se_img_metadata() {
+    fn se_img_metadata_v1() {
         let metadata = SeImgMetaData::new_v1(0x14000, 0x16000);
         let data = [
             83, 101, 73, 109, 103, 76, 110, 120, 0, 0, 0, 0, 0, 1, 64, 0, 0, 0, 0, 1, 0, 0, 0, 0,