abi: parse PlatformInfo with badram mitigation

Signed-off-by: Paul Meyer <[email protected]>

Author: katexochen

abi/abi.go

@@ -73,7 +73,7 @@ const (
 	policyDebugBit        = 19
 	policySingleSocketBit = 20
 
-	maxPlatformInfoBit = 4
+	maxPlatformInfoBit = 5
 
 	signatureOffset = 0x2A0
 	ecdsaRSsize     = 72 // From the ECDSA-P384-SHA384 format in SEV SNP API specification.
@@ -193,6 +193,9 @@ type SnpPlatformInfo struct {
 	RAPLDisabled bool
 	// CiphertextHidingDRAMEnabled indicates cypher text hiding is enabled for DRAM.
 	CiphertextHidingDRAMEnabled bool
+	// AliasCheckComplete indicates that alias detection has completed since the last system reset and there are no aliasing addresses.
+	// Mitigation for https://badram.eu/, see https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3015.html#mitigation.
+	AliasCheckComplete bool
 }
 
 // SnpPolicy represents the bitmask guest policy that governs the VM's behavior from launch.
@@ -256,6 +259,7 @@ func ParseSnpPlatformInfo(platformInfo uint64) (SnpPlatformInfo, error) {
 		ECCEnabled:                  (platformInfo & (1 << 2)) != 0,
 		RAPLDisabled:                (platformInfo & (1 << 3)) != 0,
 		CiphertextHidingDRAMEnabled: (platformInfo & (1 << 4)) != 0,
+		AliasCheckComplete:          (platformInfo & (1 << 5)) != 0,
 	}
 	reserved := platformInfo & ^uint64((1<<(maxPlatformInfoBit+1))-1)
 	if reserved != 0 {

abi/abi_test.go

@@ -244,8 +244,27 @@ func TestSnpPlatformInfo(t *testing.T) {
 			},
 		},
 		{
-			input:   32,
-			wantErr: "unrecognized platform info bit(s): 0x20",
+			input: 42,
+			want: SnpPlatformInfo{
+				TSMEEnabled:        true,
+				RAPLDisabled:       true,
+				AliasCheckComplete: true,
+			},
+		},
+		{
+			input: 63,
+			want: SnpPlatformInfo{
+				TSMEEnabled:                 true,
+				SMTEnabled:                  true,
+				ECCEnabled:                  true,
+				RAPLDisabled:                true,
+				CiphertextHidingDRAMEnabled: true,
+				AliasCheckComplete:          true,
+			},
+		},
+		{
+			input:   64,
+			wantErr: "unrecognized platform info bit(s): 0x40",
 		},
 	}
 	for _, tc := range tests {