>> 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.
>
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