Re: [PATCH v7 16/32] xen/x86: allow disabling the pmtimer

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 30/10/15 13:16, Jan Beulich wrote:
>>>> On 30.10.15 at 13:50, <roger.pau@citrix.com> wrote:
>> El 14/10/15 a les 16.37, Jan Beulich ha escrit:
>>>>>> On 02.10.15 at 17:48, <roger.pau@citrix.com> wrote:
>>>> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>>>> Cc: Jan Beulich <jbeulich@suse.com>
>>>> Cc: Andrew Cooper <andrew.cooper3@citrix.com>
>>>> ---
>>>> Changes since v6:
>>>>  - Return ENODEV in pmtimer_load if the timer is disabled.
>>>>  - hvm_acpi_power_button and hvm_acpi_sleep_button become noops if the
>>>>    pmtimer is disabled.
>>> But how are those two features connected? I don't think you can
>>> assume absence of a PM block just because there's no PM timer.
>>> Or if you want to tie them together for now, the predicate needs
>>> to be renamed.
>>>
>>>>  - Return ENODEV if pmtimer_change_ioport is called with the pmtimer
>>>>    disabled.
>>> Same here.
>> What about changing XEN_X86_EMU_PMTIMER into XEN_X86_EMU_PM and this
>> flags disables all PM stuff?
> Ah, right, that's a reasonable option.

It still might be a nice idea to split them in two, given future work.

To support hotplug properly (cpu, ram and pci), Xen needs to inject
GPEs, which comes from part of the PM infrastructure.  To support PCI
devices in the future without the whole PM infrastructure, it would be
nice to keep the split.

~Andrew

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