RE: [Patch][RFC] fix PAL_HALT ( is Re: [Xen-ia64-devel] [RFC] dumpcore is failed for PAL_HALT)

["Xu, Anthony" <anthony.xu@xxxxxxxxx>]

>> Do VTI domains implement enough ACPI to provide the OS a fake S5
>> power state?  If not, a PV-on-HVM driver could set pm_power_off and
>> use a hypercall, but that means HVM domains would need a Xen driver
>> for some pretty basic functionality.  Maybe all vcpus in cpu_halt()
>> should only be cause for a domain shutdown for VTI domains?
> I think VTI support S5, if not it should :-)
> 
In VTI side, ACPI is emulated by ACPI module of Qemu.
I think it supports S5.


Anthony.




Tristan Gingold write on 2007年1月25日 11:09:
> On Wed, Jan 24, 2007 at 09:19:09AM -0700, Alex Williamson wrote:
>> On Wed, 2007-01-24 at 11:14 +0100, tgingold@xxxxxxx wrote:
>>> Selon Isaku Yamahata <yamahata@xxxxxxxxxxxxx>:
>>> 
>>>> On Wed, Jan 24, 2007 at 11:43:37AM +0900, Akio Takebe wrote: [...]
>>>> According to SDM vol2 11.9, PAL_HALT places cpu in low power
>>>> state. Correct. 
>>> 
>>>> So the current behaviour that xen/ia64 shutdown unconditionally is
>>>> wrong.
>>> Yes, but that's the code in linux/ia64.
>>> Why linux/ia64 doesn't call the shutdown EFI runtime service ?  I
>>> don't know. Maybe Alex knows the answer.
>> 
>>    I think we need to be sure we're getting the correct expected user
>> behavior for domains.  A user expects the following on real hardware:
>> 
>>       * halt: Machine is stopped, not shutdown, not rebooted.
>>         Linux/ia64 uses PAL_HALT for this.
>>       * restart/reboot: Machine is reset.  Linux/ia64 uses
>>         efi.reset_system for this.
>>       * poweroff: Machine is turned off.  Linux/ia64 uses ACPI S5
>>         power state if pm_power_off is set, otherwise behaves as if
>> halted. 
>> 
>> So, for PV domains, cpu_halt() should just take the vcpu offline.  I
>> don't think there's any reason to special case the last vcpu going
>> offline and shutdown the domain.  That's not what real hardware does.
> Thanks for the details.  So current Xen/ia64 PAL_HALT behavior is not
> correct.
> 
>> Machine restart/reboot should (and does) happen transparently when
>> Xen catches the EFI call.  To support poweroff, I think we should set
>> pm_power_off to a Xen specific hypervisor shutdown routine.  The
>> abstraction is already in place to do this.
>> 
>> Do VTI domains implement enough ACPI to provide the OS a fake S5
>> power state?  If not, a PV-on-HVM driver could set pm_power_off and
>> use a hypercall, but that means HVM domains would need a Xen driver
>> for some pretty basic functionality.  Maybe all vcpus in cpu_halt()
>> should only be cause for a domain shutdown for VTI domains?
> I think VTI support S5, if not it should :-)
> 
> [...]
> Tristan.
> 
> _______________________________________________
> Xen-ia64-devel mailing list
> Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-ia64-devel

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel