Re: [PATCH 4/4] Userspace changes for KVM HPET (v3)

[Beth Kon <eak@us.ibm.com>]

Avi Kivity wrote:
> Beth Kon wrote:
>> Signed-off-by: Beth Kon <eak@us.ibm.com>
>>
>>
>> diff --git a/hw/hpet.c b/hw/hpet.c
>> index c7945ec..100abf5 100644
>> --- a/hw/hpet.c
>> +++ b/hw/hpet.c
>> @@ -30,6 +30,7 @@
>>  #include "console.h"
>>  #include "qemu-timer.h"
>>  #include "hpet_emul.h"
>> +#include "qemu-kvm.h"
>>  
>>  //#define HPET_DEBUG
>>  #ifdef HPET_DEBUG
>> @@ -48,6 +49,28 @@ uint32_t hpet_in_legacy_mode(void)
>>          return 0;
>>  }
>>  
>> +static void hpet_legacy_enable(void)
>> +{
>> +    if (qemu_kvm_pit_in_kernel()) {
>> +        kvm_kpit_disable();
>> +        dprintf("qemu: hpet disabled kernel pit\n");
>> +    } else {
>> +        hpet_pit_disable();
>> +        dprintf("qemu: hpet disabled userspace pit\n");
>> +    }
>> +}
>> +
>> +static void hpet_legacy_disable(void)
>> +{
>> +    if (qemu_kvm_pit_in_kernel()) {
>> +        kvm_kpit_enable();
>> +        dprintf("qemu: hpet enabled kernel pit\n");
>> +    } else {
>> +        hpet_pit_enable();
>> +        dprintf("qemu: hpet enabled userspace pit\n");
>> +    }
>> +}
>>   
> I think it's better to move these into hpet_pit_enable() and 
> hpet_pit_enable().  This avoids changing the calls below, and puts pit 
> stuff in i8254.c instead of hpet.c.
>
> Might also need to be called from hpet_load(); probably a problem in 
> upstream as well.
>
My assumption about hpet_load was that the correct pit state would be 
established via pit_load (since all saves/loads are done together).  But 
when I wrote this, I was thinking only about the userspace pit (for 
qemu). I'm not sure how the "load" concept applies to kernel state.  Do 
I need to explicitly re-enable or disable the kernel pit during load?