target/arm/arch_dump: Add SVE notes

When dumping a guest with dump-guest-memory also dump the SVE
registers if they are in use.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200120101832.18781-1-drjones@redhat.com
[PMM: fixed checkpatch nits]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 40f2c45e17..c1aedbeac0 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -980,6 +980,31 @@ void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq);
 void aarch64_sve_change_el(CPUARMState *env, int old_el,
                            int new_el, bool el0_a64);
 void aarch64_add_sve_properties(Object *obj);
+
+/*
+ * SVE registers are encoded in KVM's memory in an endianness-invariant format.
+ * The byte at offset i from the start of the in-memory representation contains
+ * the bits [(7 + 8 * i) : (8 * i)] of the register value. As this means the
+ * lowest offsets are stored in the lowest memory addresses, then that nearly
+ * matches QEMU's representation, which is to use an array of host-endian
+ * uint64_t's, where the lower offsets are at the lower indices. To complete
+ * the translation we just need to byte swap the uint64_t's on big-endian hosts.
+ */
+static inline uint64_t *sve_bswap64(uint64_t *dst, uint64_t *src, int nr)
+{
+#ifdef HOST_WORDS_BIGENDIAN
+    int i;
+
+    for (i = 0; i < nr; ++i) {
+        dst[i] = bswap64(src[i]);
+    }
+
+    return dst;
+#else
+    return src;
+#endif
+}
+
 #else
 static inline void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq) { }
 static inline void aarch64_sve_change_el(CPUARMState *env, int o,