Re: [PATCH] accel/tcg/user-exec: Fix read-modify-write of code on s390 hosts

2021-08-03 Thread Richard Henderson
On 8/3/21 9:54 AM, Ilya Leoshkevich wrote: /* ??? On linux, the non-rt signal handler has 4 (!) arguments instead - of the normal 2 arguments. The 3rd argument contains the "int_code" - from the hardware which does in fact contain the is_write value. + of the normal 2 arg

[PATCH] accel/tcg/user-exec: Fix read-modify-write of code on s390 hosts

2021-08-03 Thread Ilya Leoshkevich
x86_64 dotnet/runtime uses cmpxchg for code patching. When running it under s390x qemu-linux user, cpu_signal_handler() does not recognize this as a write and does not restore PAGE_WRITE cleared by tb_page_add(), incorrectly forwarding the signal to the guest code. Signed-off-by: Ilya Leoshkevich