tb_gen_code() assumes that tb->size must never be zero, otherwise it
may produce spurious exceptions. For x86_64 this may happen when
creating a translation block for the vsyscall page.
Fix by pretending that vsyscall translation blocks have at least one
instruction.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210519045738.1335210-2-iii@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
9b21049edd