Re: [Qemu-devel] [PATCH] target-i386: fix iret emulation correctness

[poletaev]

> Second, an IRET with HF_NMI_MASK set can be translated to _only_ the 
> reset of NMI mask followed by end of basic block.  An IRET without 
> HF_NMI_MASK instead can be translated the same way as now.

I want to make it like this, but it seems to me it can lead to zero tb size
and introduce bad side effect. What I do wrong?

case 0xcf: /* iret */
    gen_svm_check_intercept(s, pc_start, SVM_EXIT_IRET);
    if (!s->pe) {
        /* real mode */
        gen_helper_iret_real(cpu_env, tcg_const_i32(dflag - 1));
        set_cc_op(s, CC_OP_EFLAGS);
    } else if (s->vm86) {
        if (s->iopl != 3) {
            if (s->flags & HF_NMI_MASK) {
                gen_reset_hflag(s, HF_NMI_MASK);
                s->pc = pc_start;
                gen_jmp_im(pc_start - s->cs_base);
            } else {
                gen_exception(s, EXCP0D_GPF, pc_start - s->cs_base);
            }
        } else {
            gen_helper_iret_real(cpu_env, tcg_const_i32(dflag - 1));
            set_cc_op(s, CC_OP_EFLAGS);
        }
    } else {
        gen_helper_iret_protected(cpu_env, tcg_const_i32(dflag - 1),
                                  tcg_const_i32(s->pc - s->cs_base));
        set_cc_op(s, CC_OP_EFLAGS);
    }
    gen_eob(s);
    break;

Best regards, 
Dmitry Poletaev.