Re: [Xen-ia64-devel] [PATCH] emulate PAL_HALT_LIGHT on domU

[Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>]

Hi, Kevin

Thank you for your comments.

I agree your points.
I will change it as your comments.

Anyway, I should change the name of function(vcpu_get_next_timer),
because the meaning is changed.:-)

Thanks,
Atsushi SAKAI




 
>>From: Atsushi SAKAI [mailto:sakaia@xxxxxxxxxxxxxx]

>>Hi, Kevin
>>
>>Sorry for late, my mail sorting was failed.
>>Thanks for your comments.
>>
>>Anyway, I reply as follows (2items)
>>
>>1)mITC vITC relation in GuestOS
>>
>>At ParaVM GuestOS, it uses real mITC as vITC(=mITC).
>>See the below(Compare the ParaVM and the FullVM)
>> [...]
>
>Yes, your observation is correct which is the current design. Later 
>Same drift concept will be also required for para domain on itc drift 
>platform or migration.
>
>What I meant here is not the difference between vITM and mITM. 
>Currently there're two cases to manipulate machine ITM register. 
>One path is to emulate write to cr.itm for para-domain with value 
>saved in domain_itm. Another is used to drive soft timer with value 
>saved in itm_next. That's why vcpu_set_next_time needs to choose 
>the minimal value between them, to ensure timely interrupt delivery.
>
>However let's see your case. When para-domain is doing pal_halt_light, 
>you just need to register a soft time with expiration as (domain_itm - 
>current ITC) since this soft timer only serves to trigger virtual time 
>interrupt for target domain. It's unnecessary to set it as (itm_next - 
>current ITC) when itm_next<domain_itm, since we know vcpu timer 
>not expired in this case for most time. No correctness issue, and just 
>hope no waste here.
>
>Hope clearer now. :-)
>
>Thanks,
>Kevin
>


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