arm64: add CCA policy and VP context support (#106)

Add Arm CCA as a supported AArch64 isolation platform and define the
corresponding IGVM policy and VP context wire formats.

Introduce IGVM_VHT_CCA_POLICY, IGVM_VHS_CCA_POLICY, CCA policy attribute
bits, hash algorithm and LFA policy enums, and the AArch64 CCA VP
context
structure. Add parser, serializer, merge-mask fixup, and validation
support
for CCA policy headers, including reserved-field checks, ones/zeroes
mask
conflict detection, and validation that CCA policy compatibility masks
refer
to CCA platform headers.

Add AArch64 CCA VP context directive handling and round-trip tests for
CCA
IGVM files. Expose the new CCA definitions through cbindgen and add the
C API
error mapping for invalid CCA policy compatibility masks.

---------

Co-authored-by: Jiong Wang (Arm Ltd) <b-jionwang@microsoft.com>

Author: jiong-microsoft

igvm/src/c_api.rs

@@ -60,6 +60,7 @@ pub enum IgvmResult {
     IGVMAPI_UNSUPPORTED_PAGE_SIZE = -25,
     IGVMAPI_INVALID_FIXED_HEADER_ARCH = -26,
     IGVMAPI_MERGE_REVISION = -27,
+    IGVMAPI_INVALID_CCA_POLICY_COMPATIBILITY_MASK = -28,
 }
 
 type IgvmHandle = i32;
@@ -164,6 +165,9 @@ fn translate_error(error: Error) -> IgvmResult {
         Error::UnsupportedPageSize(_) => IgvmResult::IGVMAPI_UNSUPPORTED_PAGE_SIZE,
         Error::InvalidFixedHeaderArch(_) => IgvmResult::IGVMAPI_INVALID_FIXED_HEADER_ARCH,
         Error::MergeRevision => IgvmResult::IGVMAPI_MERGE_REVISION,
+        Error::InvalidCcaPolicyCompatibilityMask(_) => {
+            IgvmResult::IGVMAPI_INVALID_CCA_POLICY_COMPATIBILITY_MASK
+        }
     }
 }