The architecture specifies that mtspr/mfspr on an unknown SPR number should act as a nop in privileged mode.
I haven't removed the warning however as it can be useful for diagnosing. Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> --- target-ppc/translate.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/target-ppc/translate.c b/target-ppc/translate.c index a3de142..dd0ecc8 100644 --- a/target-ppc/translate.c +++ b/target-ppc/translate.c @@ -4351,7 +4351,10 @@ static inline void gen_op_mfspr(DisasContext *ctx) qemu_log("Trying to read invalid spr %d (0x%03x) at " TARGET_FMT_lx "\n", sprn, sprn, ctx->nip - 4); } - gen_inval_exception(ctx, POWERPC_EXCP_INVAL_SPR); + /* Only generate an exception in user space, otherwise this is a nop */ + if (ctx->pr) { + gen_inval_exception(ctx, POWERPC_EXCP_INVAL_SPR); + } } } @@ -4503,7 +4506,11 @@ static void gen_mtspr(DisasContext *ctx) } fprintf(stderr, "Trying to write invalid spr %d (0x%03x) at " TARGET_FMT_lx "\n", sprn, sprn, ctx->nip - 4); - gen_inval_exception(ctx, POWERPC_EXCP_INVAL_SPR); + + /* Only generate an exception in user space, otherwise this is a nop */ + if (ctx->pr) { + gen_inval_exception(ctx, POWERPC_EXCP_INVAL_SPR); + } } } -- 2.5.5