| Message ID | 1e517ab259c42885b0dbb49ea13db92f2df45815.1328031687.git.jan.kiszka@siemens.com |
|---|---|
| State | New |
| Headers | show |
On 01/31/2012 11:41 AM, Jan Kiszka wrote: > In legacy mode, the HPET suppresses the RTC interrupt delivery via IRQ > 8 but keeps track of the RTC output level and applies it when legacy > mode is turned off again. This value has to be preserved across save/ > restore as it cannot be reconstructed otherwise. > > Signed-off-by: Jan Kiszka<jan.kiszka@siemens.com> > --- > hw/hpet.c | 26 ++++++++++++++++++++++++++ > 1 files changed, 26 insertions(+), 0 deletions(-) > > diff --git a/hw/hpet.c b/hw/hpet.c > index aba9ea9..39b291f 100644 > --- a/hw/hpet.c > +++ b/hw/hpet.c > @@ -240,6 +240,24 @@ static int hpet_post_load(void *opaque, int version_id) > return 0; > } > > +static bool hpet_rtc_irq_level_needed(void *opaque) > +{ > + HPETState *s = opaque; > + > + return s->rtc_irq_level != 0; > +} > + > +static const VMStateDescription vmstate_hpet_rtc_irq_level = { > + .name = "hpet/rtc_irq_level", > + .version_id = 1, > + .minimum_version_id = 1, > + .minimum_version_id_old = 1, > + .fields = (VMStateField[]) { > + VMSTATE_UINT8(rtc_irq_level, HPETState), > + VMSTATE_END_OF_LIST() > + } > +}; > + This won't work. We don't clear rtc_irq_level on reset so rtc_irq_level may be high or low after reset. As such, we can't use a subsection here. We need to bump the savevm state. Regards, Anthony Liguori > static const VMStateDescription vmstate_hpet_timer = { > .name = "hpet_timer", > .version_id = 1, > @@ -273,6 +291,14 @@ static const VMStateDescription vmstate_hpet = { > VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0, > vmstate_hpet_timer, HPETTimer), > VMSTATE_END_OF_LIST() > + }, > + .subsections = (VMStateSubsection[]) { > + { > + .vmsd =&vmstate_hpet_rtc_irq_level, > + .needed = hpet_rtc_irq_level_needed, > + }, { > + /* empty */ > + } > } > }; >
On 2012-01-31 22:02, Anthony Liguori wrote: > On 01/31/2012 11:41 AM, Jan Kiszka wrote: >> In legacy mode, the HPET suppresses the RTC interrupt delivery via IRQ >> 8 but keeps track of the RTC output level and applies it when legacy >> mode is turned off again. This value has to be preserved across save/ >> restore as it cannot be reconstructed otherwise. >> >> Signed-off-by: Jan Kiszka<jan.kiszka@siemens.com> >> --- >> hw/hpet.c | 26 ++++++++++++++++++++++++++ >> 1 files changed, 26 insertions(+), 0 deletions(-) >> >> diff --git a/hw/hpet.c b/hw/hpet.c >> index aba9ea9..39b291f 100644 >> --- a/hw/hpet.c >> +++ b/hw/hpet.c >> @@ -240,6 +240,24 @@ static int hpet_post_load(void *opaque, int >> version_id) >> return 0; >> } >> >> +static bool hpet_rtc_irq_level_needed(void *opaque) >> +{ >> + HPETState *s = opaque; >> + >> + return s->rtc_irq_level != 0; >> +} >> + >> +static const VMStateDescription vmstate_hpet_rtc_irq_level = { >> + .name = "hpet/rtc_irq_level", >> + .version_id = 1, >> + .minimum_version_id = 1, >> + .minimum_version_id_old = 1, >> + .fields = (VMStateField[]) { >> + VMSTATE_UINT8(rtc_irq_level, HPETState), >> + VMSTATE_END_OF_LIST() >> + } >> +}; >> + > > This won't work. We don't clear rtc_irq_level on reset so rtc_irq_level > may be high or low after reset. As such, we can't use a subsection > here. We need to bump the savevm state. rtc_irq_level is updated during reset by the connected RTC device. It clears its IRQ line. Jan
On 01/31/2012 04:05 PM, Jan Kiszka wrote: > On 2012-01-31 22:02, Anthony Liguori wrote: >> On 01/31/2012 11:41 AM, Jan Kiszka wrote: >>> In legacy mode, the HPET suppresses the RTC interrupt delivery via IRQ >>> 8 but keeps track of the RTC output level and applies it when legacy >>> mode is turned off again. This value has to be preserved across save/ >>> restore as it cannot be reconstructed otherwise. >>> >>> Signed-off-by: Jan Kiszka<jan.kiszka@siemens.com> >>> --- >>> hw/hpet.c | 26 ++++++++++++++++++++++++++ >>> 1 files changed, 26 insertions(+), 0 deletions(-) >>> >>> diff --git a/hw/hpet.c b/hw/hpet.c >>> index aba9ea9..39b291f 100644 >>> --- a/hw/hpet.c >>> +++ b/hw/hpet.c >>> @@ -240,6 +240,24 @@ static int hpet_post_load(void *opaque, int >>> version_id) >>> return 0; >>> } >>> >>> +static bool hpet_rtc_irq_level_needed(void *opaque) >>> +{ >>> + HPETState *s = opaque; >>> + >>> + return s->rtc_irq_level != 0; >>> +} >>> + >>> +static const VMStateDescription vmstate_hpet_rtc_irq_level = { >>> + .name = "hpet/rtc_irq_level", >>> + .version_id = 1, >>> + .minimum_version_id = 1, >>> + .minimum_version_id_old = 1, >>> + .fields = (VMStateField[]) { >>> + VMSTATE_UINT8(rtc_irq_level, HPETState), >>> + VMSTATE_END_OF_LIST() >>> + } >>> +}; >>> + >> >> This won't work. We don't clear rtc_irq_level on reset so rtc_irq_level >> may be high or low after reset. As such, we can't use a subsection >> here. We need to bump the savevm state. > > rtc_irq_level is updated during reset by the connected RTC device. It > clears its IRQ line. Ah, that's subtle and warrants a comment :-) Probably worth adding an s->rtc_irq_level = 0 in reset just to be extra safe. Regards, Anthony Liguori > > Jan
On 2012-01-31 23:38, Anthony Liguori wrote: > On 01/31/2012 04:05 PM, Jan Kiszka wrote: >> On 2012-01-31 22:02, Anthony Liguori wrote: >>> On 01/31/2012 11:41 AM, Jan Kiszka wrote: >>>> In legacy mode, the HPET suppresses the RTC interrupt delivery via IRQ >>>> 8 but keeps track of the RTC output level and applies it when legacy >>>> mode is turned off again. This value has to be preserved across save/ >>>> restore as it cannot be reconstructed otherwise. >>>> >>>> Signed-off-by: Jan Kiszka<jan.kiszka@siemens.com> >>>> --- >>>> hw/hpet.c | 26 ++++++++++++++++++++++++++ >>>> 1 files changed, 26 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/hw/hpet.c b/hw/hpet.c >>>> index aba9ea9..39b291f 100644 >>>> --- a/hw/hpet.c >>>> +++ b/hw/hpet.c >>>> @@ -240,6 +240,24 @@ static int hpet_post_load(void *opaque, int >>>> version_id) >>>> return 0; >>>> } >>>> >>>> +static bool hpet_rtc_irq_level_needed(void *opaque) >>>> +{ >>>> + HPETState *s = opaque; >>>> + >>>> + return s->rtc_irq_level != 0; >>>> +} >>>> + >>>> +static const VMStateDescription vmstate_hpet_rtc_irq_level = { >>>> + .name = "hpet/rtc_irq_level", >>>> + .version_id = 1, >>>> + .minimum_version_id = 1, >>>> + .minimum_version_id_old = 1, >>>> + .fields = (VMStateField[]) { >>>> + VMSTATE_UINT8(rtc_irq_level, HPETState), >>>> + VMSTATE_END_OF_LIST() >>>> + } >>>> +}; >>>> + >>> >>> This won't work. We don't clear rtc_irq_level on reset so rtc_irq_level >>> may be high or low after reset. As such, we can't use a subsection >>> here. We need to bump the savevm state. >> >> rtc_irq_level is updated during reset by the connected RTC device. It >> clears its IRQ line. > > Ah, that's subtle and warrants a comment :-) > > Probably worth adding an s->rtc_irq_level = 0 in reset just to be extra > safe. Agreed. Will do. Thanks, Jan
diff --git a/hw/hpet.c b/hw/hpet.c index aba9ea9..39b291f 100644 --- a/hw/hpet.c +++ b/hw/hpet.c @@ -240,6 +240,24 @@ static int hpet_post_load(void *opaque, int version_id) return 0; } +static bool hpet_rtc_irq_level_needed(void *opaque) +{ + HPETState *s = opaque; + + return s->rtc_irq_level != 0; +} + +static const VMStateDescription vmstate_hpet_rtc_irq_level = { + .name = "hpet/rtc_irq_level", + .version_id = 1, + .minimum_version_id = 1, + .minimum_version_id_old = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT8(rtc_irq_level, HPETState), + VMSTATE_END_OF_LIST() + } +}; + static const VMStateDescription vmstate_hpet_timer = { .name = "hpet_timer", .version_id = 1, @@ -273,6 +291,14 @@ static const VMStateDescription vmstate_hpet = { VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0, vmstate_hpet_timer, HPETTimer), VMSTATE_END_OF_LIST() + }, + .subsections = (VMStateSubsection[]) { + { + .vmsd = &vmstate_hpet_rtc_irq_level, + .needed = hpet_rtc_irq_level_needed, + }, { + /* empty */ + } } };
In legacy mode, the HPET suppresses the RTC interrupt delivery via IRQ 8 but keeps track of the RTC output level and applies it when legacy mode is turned off again. This value has to be preserved across save/ restore as it cannot be reconstructed otherwise. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> --- hw/hpet.c | 26 ++++++++++++++++++++++++++ 1 files changed, 26 insertions(+), 0 deletions(-)