Avi Kivity wrote:
> On 04/14/2010 03:37 PM, Jan Kiszka wrote:
>> Avi Kivity wrote:
>>
>>> On 04/14/2010 03:11 PM, Jan Kiszka wrote:
>>>
>>>> When a fault triggers a task switch, the error code, if it exists, has
>>>> to be pushed on the new task's stack. Implement the missing bits.
>>>>
>>>>
>>>> @@ -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;
>>>>
>>>>
>>> Don't these depend on the attributes of the segment as well?
>>>
>> Not on the segment, but actually on the gate size. Will fix.
>>
>
> The TSS descriptor (gate doesn't have a size). But isn't it possible to
> have a 32-bit TSS with a 16-bit CS/SS?
Might be possible, but will cause troubles as the spec says:
"The error code is pushed on the stack as a doubleword or word
(depending on the default interrupt, trap, or task gate size)."
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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