[Qemu-devel] [PATCH] target-arm/translate-a64: Fix wrong mmu_idx usage for LDT/STT

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

The LDT/STT (load/store unprivileged) instruction decode was using
the wrong MMU index value. This meant that instead of these insns
being "always access as if user-mode regardless of current privilege"
they were "always access as if kernel-mode regardless of current
privilege". This went unnoticed because AArch64 Linux doesn't use
these instructions.

Cc: qemu-stable@nongnu.org

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I'm not counting this as a security issue because I'm assuming
nobody treats TCG guests as a security boundary (certainly I
would not recommend doing so...)
---
 target-arm/translate-a64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index 80d2359..dac2f63 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -2107,7 +2107,7 @@ static void disas_ldst_reg_imm9(DisasContext *s, uint32_t insn)
         }
     } else {
         TCGv_i64 tcg_rt = cpu_reg(s, rt);
-        int memidx = is_unpriv ? 1 : get_mem_index(s);
+        int memidx = is_unpriv ? MMU_USER_IDX : get_mem_index(s);
 
         if (is_store) {
             do_gpr_st_memidx(s, tcg_rt, tcg_addr, size, memidx);
-- 
1.9.1