Il 30/07/2014 09:01, Pavel Dovgaluk ha scritto:
>
>> -----Original Message-----
>> From: Paolo Bonzini [mailto:paolo.bonz...@gmail.com] On Behalf Of Paolo
>> Bonzini
>> Sent: Monday, July 28, 2014 1:59 PM
>> To: Pavel Dovgalyuk; qemu-devel@nongnu.org
>> Cc: peter.mayd...@linaro.org; peter.crosthwa...@xilinx.com;
>> mark.bur...@greensocs.com;
>> r...@ispras.ru; batuz...@ispras.ru; fred.kon...@greensocs.com
>> Subject: Re: [RFC PATCH v2 06/49] serial: fixing vmstate for save/restore
>>
>> Il 17/07/2014 13:02, Pavel Dovgalyuk ha scritto:
>>> - .version_id = 3,
>>> + .version_id = 4,
>>> .minimum_version_id = 2,
>>> .pre_save = serial_pre_save,
>>> .post_load = serial_post_load,
>>> .fields = (VMStateField[]) {
>>> VMSTATE_UINT16_V(divider, SerialState, 2),
>>> VMSTATE_UINT8(rbr, SerialState),
>>> + VMSTATE_UINT8_V(thr, SerialState, 4),
>>> + VMSTATE_UINT8_V(tsr, SerialState, 4),
>>> VMSTATE_UINT8(ier, SerialState),
>>> VMSTATE_UINT8(iir, SerialState),
>>> VMSTATE_UINT8(lcr, SerialState),
>>> @@ -613,6 +627,15 @@ const VMStateDescription vmstate_serial = {
>>> VMSTATE_UINT8(msr, SerialState),
>>> VMSTATE_UINT8(scr, SerialState),
>>> VMSTATE_UINT8_V(fcr_vmstate, SerialState, 3),
>>> + VMSTATE_INT32_V(thr_ipending, SerialState, 4),
>>
>> Subsection, only migrated if it doesn't match "(s->iir & UART_IIR_ID) ==
>> UART_IIR_THRI".
>
> thr_ipending is set here:
> if (s->lsr & UART_LSR_THRE) {
> s->lsr |= UART_LSR_TEMT;
> s->thr_ipending = 1;
> serial_update_irq(s);
> }
>
> serial_update_irq has several if-else branches. One of them sets tmp_iir =
> UART_IIR_THRI, as you said.
> Couldn't be possible, that this branch will not be reached, because one of
> the previous ones will be executed?
Yes, what I wrote is equivalent to the following:
int serial_pre_load(void *opaque)
{
SerialState *s = opaque;
s->thr_ipending = -1;
return 0;
}
int serial_post_load(void *opaque)
{
SerialState *s = opaque;
...
if (s->thr_ipending == -1) {
s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
}
...
}
bool thr_ipending_needed(void *opaque)
{
SerialState *s = opaque;
bool expected_value = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
return s->thr_pending != expected_value;
}
The case you mention is exactly the one that will cause thr_ipending to
be migrated.
Paolo
