Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpregs.h |  6 ++++++
 target/arm/helper.c | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/target/arm/cpregs.h b/target/arm/cpregs.h
index e1d54baead..0b0004eff9 100644
--- a/target/arm/cpregs.h
+++ b/target/arm/cpregs.h
@@ -21,6 +21,7 @@
 #ifndef TARGET_ARM_CPREGS_H
 #define TARGET_ARM_CPREGS_H
 
+#include "qemu/int128.h"
 #include "hw/registerfields.h"
 #include "exec/memop.h"
 #include "target/arm/kvm-consts.h"
@@ -1124,6 +1125,11 @@ uint64_t raw_read(CPUARMState *env, const ARMCPRegInfo *ri);
 /* CPWriteFn that just writes the value to ri->fieldoffset */
 void raw_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value);
 
+/* Likewise for 128-bit fields. */
+Int128 raw_read128(CPUARMState *env, const ARMCPRegInfo *opaque);
+void raw_write128(CPUARMState *env, const ARMCPRegInfo *opaque,
+                  uint64_t lo, uint64_t hi);
+
 /*
  * CPResetFn that does nothing, for use if no reset is required even
  * if fieldoffset is non zero.
diff --git a/target/arm/helper.c b/target/arm/helper.c
index c240edf182..e321f404e6 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -59,6 +59,8 @@ int compare_u64(const void *a, const void *b)
     (*(uint32_t *)((char *)(env) + (ri)->fieldoffset))
 #define CPREG_FIELD64(env, ri) \
     (*(uint64_t *)((char *)(env) + (ri)->fieldoffset))
+#define CPREG_FIELD128_H64(env, ri) \
+    (*(uint64_t *)((char *)(env) + (ri)->fieldoffsethi))
 
 uint64_t raw_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
@@ -88,8 +90,27 @@ void raw_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
     }
 }
 
+Int128 raw_read128(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    assert(ri->type & ARM_CP_128BIT);
+    assert(ri->fieldoffset);
+    assert(ri->fieldoffsethi);
+    return int128_make128(CPREG_FIELD64(env, ri), CPREG_FIELD128_H64(env, ri));
+}
+
+void raw_write128(CPUARMState *env, const ARMCPRegInfo *ri,
+                  uint64_t valuelo, uint64_t valuehi)
+{
+    assert(ri->type & ARM_CP_128BIT);
+    assert(ri->fieldoffset);
+    assert(ri->fieldoffsethi);
+    CPREG_FIELD64(env, ri) = valuelo;
+    CPREG_FIELD128_H64(env, ri) = valuehi;
+}
+
 #undef CPREG_FIELD32
 #undef CPREG_FIELD64
+#undef CPREG_FIELD128_H64
 
 static void *raw_ptr(CPUARMState *env, const ARMCPRegInfo *ri)
 {
-- 
2.43.0

On Tue, 14 Oct 2025 at 21:17, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/cpregs.h |  6 ++++++
>  target/arm/helper.c | 21 +++++++++++++++++++++
>  2 files changed, 27 insertions(+)
>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM