Commit 5904ae4e authored by Jan Kiszka's avatar Jan Kiszka Committed by Anthony Liguori
Browse files

hpet: Save/restore cached RTC IRQ level 



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.

To document that a raised rtc_irq_level won't survive a vmload without
a hpet/rtc_irq_level subsection, add an explicit clearing to the reset
handler.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 61b7b67d

hw/hpet.c

+29 −0
Original line number Diff line number Diff line
@@ -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 */

        }

    }

};
@@ -636,6 +662,9 @@ static void hpet_reset(DeviceState *d) 
    hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;

    hpet_cfg.hpet[s->hpet_id].address = sysbus_from_qdev(d)->mmio[0].addr;

    count = 1;



    /* to document that the RTC lowers its output on reset as well */

    s->rtc_irq_level = 0;

}



static void hpet_handle_rtc_irq(void *opaque, int n, int level)