Re: [PATCH v2 for-8.0] target/s390x/tcg: Fix and improve the SACF instruction

[Ilya Leoshkevich]

On Thu, 2022-12-01 at 19:44 +0100, Thomas Huth wrote:
> The SET ADDRESS SPACE CONTROL FAST instruction is not privileged, it
> can be
> used from problem space, too. Just the switching to the home address
> space
> is privileged and should still generate a privilege exception. This
> bug is
> e.g. causing programs like Java that use the "getcpu" vdso kernel
> function
> to crash (see
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=990417#26 ).
> 
> While we're at it, also check if DAT is not enabled. In that case the
> instruction is supposed to generate a special operation exception.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/655
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  target/s390x/tcg/insn-data.h.inc | 2 +-
>  target/s390x/tcg/cc_helper.c     | 7 +++++++
>  2 files changed, 8 insertions(+), 1 deletion(-)

Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>