Re: [Qemu-devel] [PATCH RFC 0/7] pass cpu online/offline event bewteen QEMU and linux kernel by ACPI Embedded Controller

[Igor Mammedov]

On Wed, 29 May 2013 09:47:35 +0800
liguang <address@hidden> wrote:

> patch 1 adds ACPI Embedded Controller (EC),
> refer-to:
> ACPI SPEC v5 chapter 12
> "ACPI Embedded Controller Interface Specification"
> 
> EC is a standard ACPI device, it plays flexible roles,
> especially be event carrier, it can pass events between platform
> and OS, so OS can execute _Qxx method which defined
> by yourself and query EC's ACPI space which can be a buffer for
_Qxx is defined in ACPI tables (i.e. firmware) and OS can just execute
it.

> many purposes
> 
> here, I want to deliver CPU online/offline event between
> OS and QEMU for CPU hotplug feature, then we will don't
> need to "echo 1 > /sys/devices/system/cpu/cpu1/online"
> again after 'cpu-add' and also for offline to do real cpu
> removal.
> what I am trying to do is emulated physical addition/removal
> (like described by linux kernel document for cpu hotplug --
> linux-2.6/Documentation/cpu-hotplug.txt) for QEMU.
> 
> these RFC patches are sent for demo what I am trying to do.
> 
> the design process simply like following:
> 
> cpu-add/del --> EC space & sci setting --> kernel EC driver gpe handler
>                                                   I
>                                                   V
>                                       listen cpu hotplug event
Does this and following parts mean that guest OS must have platform specific 
driver
to handle custom event?
Is there OS that can do it and below without a new driver?

>                                                   I
>                                                   V
>                                       query EC space for cpu status
>                                                   I
>                                                   V
>                                                                       trigger 
> cpu online/offline process
> 
> 
> Li Guang (7)
>        acpi: add ACPI Embedded Controller support
>        ich9: add notifer for ec to generate sci
>        ec: add operations for _Qxx events
>        piix4: add notifer for ec to generate sci
>        piix4: add events for cpu hotplug
>        qmp: add 'cpu-del' command
>        pc: add EC qdev init for piix & q35
> 
> default-configs/x86_64-softmmu.mak |   1 +
> hw/acpi/Makefile.objs              |   1 +
> hw/acpi/ec.c                       | 225 ++++++++++++++++++++++++++++++++++++
> hw/acpi/ich9.c                     |  15 +++++++++++++++
> hw/acpi/piix4.c                    |  22 ++++++++++++++
> hw/i386/pc.c                       |  30 ++++++++++++++++++++++++++++--
> hw/i386/pc_piix.c                  |   7 +
> hw/i386/pc_q35.c                   |   6 +
> include/hw/acpi/ec.h               |  39 ++++++
> include/hw/acpi/ich9.h             |   1 +
> include/hw/boards.h                |   5 +++--
> include/hw/i386/pc.h               |   1 +
> qapi-schema.json                   |  13 +++++++++++++
> qmp-commands.hx                    |  23 +++++++++++++++++++++++
> qmp.c                              |   9 +++++++++
> 15 files changed, 390 insertions(+), 8 deletions(-)
>  create mode 100644 hw/acpi/ec.c
>  create mode 100644 include/hw/acpi/ec.h
>