Re: [Xen-ia64-devel] RFC: adding a dom0_firmware_setup hypercall

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Mardi 30 Mai 2006 16:42, Tian, Kevin a écrit :
> From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>
> >Sent: 2006年5月30日 15:57
> >
> >> Since it's a RFC, it's better if, you could give more detail description
> >> about why you need this change and what benefit people can achieve
> >> from. For example:
> >>    - Why do you like to kill DOM0_SETVPUCONTEXT, which has
> >> common concept and has been used for ia64 now?
> >
> >I don't want to kill it.
>
> Good.
Also note setvcpucontext is still called but only to initialize the vcpu.

> >>    - Why is it the first step toward save&restore?
> >
> >Currently, SETVPUCONTEXT has side effects: initializing the domain.
> >SETVPUCONTEXT has to be used during restore to set all VCPUs.  If it
> >also
> >initialize the domain (ie, set the firmware), bad things may happen.
>
> I think SETVCPUCONTEXT is the standard interface either for domain
> creation or restore
This is ok.

> and some special things are only required to be done
> for vcpu 0.
This is the beginning of kludges.

> Actually debugger also utilizes SETVCPUCONTEXT to update
> the modified context of target vcpu.
This is Ok.

> If, the code for ia64 version
> SETVCPUCONTEXT is not ready for some reason, I think we should try
> to fix arch_set_info_guest first.
No, it is too early.

> >> Based on those information, people can better understand your
> >> proposal and thus give appropriate comments.
> >>
> >> BTW, why can't those new fields (or whole firmware setup structure) be
> >> put in vcpu_guest_context without adding a new dom0_op?
> >
> >For the above reason.
> >I think vcpu_guest_context should only modify the vcpu, not the domain.
>
> Vcpu 0 is special to take responsibility of initializing some domain wise
> content.
Yes, but it became too kludgy.

Tristan.

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