Gleb Natapov wrote: > On Wed, Apr 14, 2010 at 02:11:39PM +0200, Jan Kiszka wrote: >> static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, >> - struct x86_emulate_ops *ops, >> - u16 tss_selector, int reason) >> + struct x86_emulate_ops *ops, >> + u16 tss_selector, int reason, >> + bool has_error_code, u32 error_code) >> { >> struct desc_struct curr_tss_desc, next_tss_desc; >> int ret; >> @@ -2416,12 +2417,23 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt, >> ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu); >> ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu); >> >> + if (ret == X86EMUL_CONTINUE && has_error_code) { > It looks like we shouldn't get here if ret != X86EMUL_CONTINUE in the > first place. This check should be done just after call to > task_switch_16/32. Not directly related to your patch, but still... Will do this in a preparational patch. > >> @@ -2416,12 +2417,23 @@ static int emulator_do_task_switch(struct >> x86_emulate_ctxt *ctxt, >> ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, >> ctxt->vcpu); >> ops->set_segment_selector(tss_selector, VCPU_SREG_TR, >> ctxt->vcpu); >> >> + if (ret == X86EMUL_CONTINUE && has_error_code) { >> + struct decode_cache *c = &ctxt->decode; >> + >> + c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 >> : 2; >> + c->lock_prefix = 0; >> + c->src.val = (unsigned long) error_code; >> + emulate_push(ctxt); >> + ret = writeback(ctxt, ops); >> + } > I would move writeback() to emulator_task_switch(). Just make > c->dst.type = OP_NONE if writeback is not needed. I should dramatically increase the overhead for the common case. :) Yeah, can do so if preferred. Thanks, Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html