[PULL 09/28] tests/tcg/aarch64/system/rme_gdi.c: Very basic test of GDI

[Peter Maydell <peter.maydell@linaro.org>]

From: Jim MacArthur <jim.macarthur@linaro.org>

Simply tests GDI's prerequisites; that if GDI is enabled then
so are FEAT_RME and FEAT_RME_GPC2.

Signed-off-by: Jim MacArthur <jim.macarthur@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20260421-jmac-feat_rme_gdi-v3-4-ecd20c77eae1@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 tests/tcg/aarch64/system/rme_gdi.c | 46 ++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 tests/tcg/aarch64/system/rme_gdi.c

diff --git a/tests/tcg/aarch64/system/rme_gdi.c b/tests/tcg/aarch64/system/rme_gdi.c
new file mode 100644
index 0000000000..e869943a13
--- /dev/null
+++ b/tests/tcg/aarch64/system/rme_gdi.c
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ * FEAT_RME_GDI Feature presence and enabled bits test
+ *
+ * Copyright (c) 2026 Linaro Ltd
+ *
+ */
+
+#include <stdint.h>
+#include <minilib.h>
+
+#define ID_AA64PFR0_EL1 "S3_0_C0_C4_0"
+#define ID_AA64MMFR4_EL1 "S3_0_C0_C7_4"
+
+int main()
+{
+    uint64_t mmfr4;
+    uint64_t pfr0;
+    int rme_status;
+    int rmegdi_status;
+
+    asm("mrs %[pfr0], " ID_AA64PFR0_EL1 "\n\t"
+        : [pfr0] "=r" (pfr0));
+
+    /* rme_status is 1 for RME, 2 for RME + GPC2, 3 for RME+GPC3 */
+    rme_status = (pfr0 >> 52) & 0xF;
+
+    asm("mrs %[mmfr4], " ID_AA64MMFR4_EL1 "\n\t"
+        : [mmfr4] "=r" (mmfr4));
+
+    rmegdi_status = ((mmfr4 >> 28) & 0xF);
+
+    if (rmegdi_status < 1) {
+        ml_printf("SKIP: GDI not implemented\n");
+        return 0;
+    }
+
+    /* Check FEAT_RME and FEAT_RME_GPC2 also present */
+    if (rme_status < 2) {
+        ml_printf("FAIL: GDI is %d, but RME is %d; RME should be >= 2\n",
+                  rmegdi_status, rme_status);
+        return 1;
+    }
+    return 0;
+}
-- 
2.43.0