Re: [PATCH 5/7 v6] introduce a new qom device to deal with panicked event

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-07-18 03:54, Wen Congyang wrote:
> At 07/06/2012 07:05 PM, Jan Kiszka Wrote:
>> On 2012-07-06 11:41, Wen Congyang wrote:
>>> If the target is x86/x86_64, the guest's kernel will write 0x01 to the
>>> port KVM_PV_PORT when it is panciked. This patch introduces a new qom
>>> device kvm_pv_ioport to listen this I/O port, and deal with panicked
>>> event according to panicked_action's value. The possible actions are:
>>> 1. emit QEVENT_GUEST_PANICKED only
>>> 2. emit QEVENT_GUEST_PANICKED and pause the guest
>>> 3. emit QEVENT_GUEST_PANICKED and poweroff the guest
>>> 4. emit QEVENT_GUEST_PANICKED and reset the guest
>>>
>>> I/O ports does not work for some targets(for example: s390). And you
>>> can implement another qom device, and include it's code into pv_event.c
>>> for such target.
>>>
>>> Note: if we emit QEVENT_GUEST_PANICKED only, and the management
>>> application does not receive this event(the management may not
>>> run when the event is emitted), the management won't know the
>>> guest is panicked.
>>>
>>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>>> ---
>>>  hw/kvm/Makefile.objs |    2 +-
>>>  hw/kvm/pv_event.c    |   73 +++++++++++++++++++++++++++
>>>  hw/kvm/pv_ioport.c   |  133 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>  kvm-stub.c           |    9 +++
>>>  kvm.h                |    3 +
>>>  vl.c                 |    4 ++
>>>  6 files changed, 223 insertions(+), 1 deletions(-)
>>>  create mode 100644 hw/kvm/pv_event.c
>>>  create mode 100644 hw/kvm/pv_ioport.c
>>>
>>> diff --git a/hw/kvm/Makefile.objs b/hw/kvm/Makefile.objs
>>> index 226497a..23e3b30 100644
>>> --- a/hw/kvm/Makefile.objs
>>> +++ b/hw/kvm/Makefile.objs
>>> @@ -1 +1 @@
>>> -obj-$(CONFIG_KVM) += clock.o apic.o i8259.o ioapic.o i8254.o
>>> +obj-$(CONFIG_KVM) += clock.o apic.o i8259.o ioapic.o i8254.o pv_event.o
>>> diff --git a/hw/kvm/pv_event.c b/hw/kvm/pv_event.c
>>> new file mode 100644
>>> index 0000000..d7ded37
>>> --- /dev/null
>>> +++ b/hw/kvm/pv_event.c
>>> @@ -0,0 +1,73 @@
>>> +/*
>>> + * QEMU KVM support, paravirtual event device
>>> + *
>>> + * Copyright Fujitsu, Corp. 2012
>>> + *
>>> + * Authors:
>>> + *     Wen Congyang <wency@cn.fujitsu.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
>>> + * See the COPYING file in the top-level directory.
>>> + *
>>> + */
>>> +
>>> +#include <linux/kvm_para.h>
>>> +#include <asm/kvm_para.h>
>>> +#include <qobject.h>
>>> +#include <qjson.h>
>>> +#include <monitor.h>
>>> +#include <sysemu.h>
>>> +#include <kvm.h>
>>> +
>>> +/* Possible values for action parameter. */
>>> +#define PANICKED_REPORT     1   /* emit QEVENT_GUEST_PANICKED only */
>>> +#define PANICKED_PAUSE      2   /* emit QEVENT_GUEST_PANICKED and pause VM */
>>> +#define PANICKED_POWEROFF   3   /* emit QEVENT_GUEST_PANICKED and quit VM */
>>> +#define PANICKED_RESET      4   /* emit QEVENT_GUEST_PANICKED and reset VM */
>>> +
>>> +static int panicked_action = PANICKED_REPORT;
>>
>> Avoid global variables please when there are device states. This one is
>> unneeded anyway (and will generate warnings when build without KVM_PV_PORT).
> 
> Hmm, do you mean introduce another qom device to store event action?

I think you should be fine with one device per bus binding, but those
will consist of a common event layer and just different I/O layers (for
bus registration and access).

Jan

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