Re: [Qemu-devel] [PATCH v9 5/6] introduce a new qom device to deal with panicked event

[Jan Kiszka <jan.kiszka@web.de>]

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On 2012-08-24 08:33, Wen Congyang wrote:
> At 08/24/2012 02:21 PM, Jan Kiszka Wrote:
>> On 2012-08-24 08:05, Wen Congyang wrote:
>>> At 08/23/2012 06:51 PM, Jan Kiszka Wrote:
>>>> On 2012-08-23 04:32, Wen Congyang wrote:
>>>>> If the target is x86/x86_64, the guest's kernel will write 0x01 to the
>>>>> port KVM_PV_EVENT_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    |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>  hw/pc_piix.c         |    9 +++
>>>>>  kvm.h                |    2 +
>>>>>  4 files changed, 202 insertions(+), 1 deletions(-)
>>>>>  create mode 100644 hw/kvm/pv_event.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..c03dd22
>>>>> --- /dev/null
>>>>> +++ b/hw/kvm/pv_event.c
>>>>> @@ -0,0 +1,190 @@
>>>>> +/*
>>>>> + * 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 */
>>>>> +
>>>>> +#define PV_EVENT_DRIVER     "kvm_pv_event"
>>>>> +
>>>>> +struct PVEventAction {
>>>>> +    char *panicked_action;
>>>>> +    int panicked_action_value;
>>>>> +};
>>>>> +
>>>>> +#define DEFINE_PV_EVENT_PROPERTIES(_state, _conf)   \
>>>>> +    DEFINE_PROP_STRING("panicked_action", _state, _conf.panicked_action)
>>>>> +
>>>>> +static void panicked_mon_event(const char *action)
>>>>> +{
>>>>> +    QObject *data;
>>>>> +
>>>>> +    data = qobject_from_jsonf("{ 'action': %s }", action);
>>>>> +    monitor_protocol_event(QEVENT_GUEST_PANICKED, data);
>>>>> +    qobject_decref(data);
>>>>> +}
>>>>> +
>>>>> +static void panicked_perform_action(uint32_t panicked_action)
>>>>> +{
>>>>> +    switch (panicked_action) {
>>>>> +    case PANICKED_REPORT:
>>>>> +        panicked_mon_event("report");
>>>>> +        break;
>>>>> +
>>>>> +    case PANICKED_PAUSE:
>>>>> +        panicked_mon_event("pause");
>>>>> +        vm_stop(RUN_STATE_GUEST_PANICKED);
>>>>> +        break;
>>>>> +
>>>>> +    case PANICKED_POWEROFF:
>>>>> +        panicked_mon_event("poweroff");
>>>>> +        qemu_system_shutdown_request();
>>>>> +        break;
>>>>> +
>>>>> +    case PANICKED_RESET:
>>>>> +        panicked_mon_event("reset");
>>>>> +        qemu_system_reset_request();
>>>>> +        break;
>>>>> +    }
>>>>> +}
>>>>> +
>>>>> +static uint64_t supported_event(void)
>>>>> +{
>>>>> +    return 1 << KVM_PV_FEATURE_PANICKED;
>>>>> +}
>>>>> +
>>>>> +static void handle_event(int event, struct PVEventAction *conf)
>>>>> +{
>>>>> +    if (event == KVM_PV_EVENT_PANICKED) {
>>>>> +        panicked_perform_action(conf->panicked_action_value);
>>>>> +    }
>>>>> +}
>>>>> +
>>>>> +static int pv_event_init(struct PVEventAction *conf)
>>>>> +{
>>>>> +    if (!conf->panicked_action) {
>>>>> +        conf->panicked_action_value = PANICKED_REPORT;
>>>>> +    } else if (strcasecmp(conf->panicked_action, "none") == 0) {
>>>>> +        conf->panicked_action_value = PANICKED_REPORT;
>>>>> +    } else if (strcasecmp(conf->panicked_action, "pause") == 0) {
>>>>> +        conf->panicked_action_value = PANICKED_PAUSE;
>>>>> +    } else if (strcasecmp(conf->panicked_action, "poweroff") == 0) {
>>>>> +        conf->panicked_action_value = PANICKED_POWEROFF;
>>>>> +    } else if (strcasecmp(conf->panicked_action, "reset") == 0) {
>>>>> +        conf->panicked_action_value = PANICKED_RESET;
>>>>> +    } else {
>>>>> +        return -1;
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +#if defined(KVM_PV_EVENT_PORT)
>>>>> +
>>>>> +#include "hw/isa.h"
>>>>> +
>>>>> +typedef struct {
>>>>> +    ISADevice dev;
>>>>> +    struct PVEventAction conf;
>>>>> +    MemoryRegion ioport;
>>>>> +} PVIOPortState;
>>>>> +
>>>>> +static uint64_t pv_io_read(void *opaque, target_phys_addr_t addr, unsigned size)
>>>>> +{
>>>>> +    return supported_event();
>>>>> +}
>>>>> +
>>>>> +static void pv_io_write(void *opaque, target_phys_addr_t addr, uint64_t val,
>>>>> +                        unsigned size)
>>>>> +{
>>>>> +    PVIOPortState *s = opaque;
>>>>> +
>>>>> +    handle_event(val, &s->conf);
>>>>> +}
>>>>> +
>>>>> +static const MemoryRegionOps pv_io_ops = {
>>>>> +    .read = pv_io_read,
>>>>> +    .write = pv_io_write,
>>>>> +    .impl = {
>>>>> +        .min_access_size = 4,
>>>>> +        .max_access_size = 4,
>>>>> +    },
>>>>> +};
>>>>> +
>>>>> +static int pv_ioport_initfn(ISADevice *dev)
>>>>> +{
>>>>> +    PVIOPortState *s = DO_UPCAST(PVIOPortState, dev, dev);
>>>>> +
>>>>> +    if (pv_event_init(&s->conf) < 0) {
>>>>> +        return -1;
>>>>> +    }
>>>>> +
>>>>> +    memory_region_init_io(&s->ioport, &pv_io_ops, s, "pv_event", 1);
>>>>> +    isa_register_ioport(dev, &s->ioport, KVM_PV_EVENT_PORT);
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static Property pv_ioport_properties[] = {
>>>>> +    DEFINE_PV_EVENT_PROPERTIES(PVIOPortState, conf),
>>>>> +    DEFINE_PROP_END_OF_LIST(),
>>>>> +};
>>>>> +
>>>>> +static void pv_ioport_class_init(ObjectClass *klass, void *data)
>>>>> +{
>>>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>>>> +    ISADeviceClass *ic = ISA_DEVICE_CLASS(klass);
>>>>> +
>>>>> +    ic->init = pv_ioport_initfn;
>>>>> +    dc->no_user = 1;
>>>>> +    dc->props = pv_ioport_properties;
>>>>> +}
>>>>> +
>>>>> +static TypeInfo pv_ioport_info = {
>>>>> +    .name          = PV_EVENT_DRIVER,
>>>>> +    .parent        = TYPE_ISA_DEVICE,
>>>>> +    .instance_size = sizeof(PVIOPortState),
>>>>> +    .class_init    = pv_ioport_class_init,
>>>>> +};
>>>>> +
>>>>> +static void pv_ioport_register_types(void)
>>>>> +{
>>>>> +    type_register_static(&pv_ioport_info);
>>>>> +}
>>>>> +
>>>>> +type_init(pv_ioport_register_types)
>>>>> +
>>>>> +void kvm_pv_event_init(void *opaque)
>>>>> +{
>>>>> +    ISABus *bus = opaque;
>>>>> +    ISADevice *dev;
>>>>> +
>>>>> +    dev = isa_create(bus, PV_EVENT_DRIVER);
>>>>> +    qdev_init_nofail(&dev->qdev);
>>>>> +}
>>>>> +
>>>>> +#else
>>>>> +void kvm_pv_event_init(void *opaque)
>>>>> +{
>>>>
>>>> Some comment that this stub requires an implementation whenever it is
>>>> actually built would be helpful. Something that explains a different
>>>> transport than PIO will be needed.
>>>
>>> OK
>>>
>>>>
>>>>> +}
>>>>> +#endif
>>>>> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
>>>>> index 88ff041..f73fb85 100644
>>>>> --- a/hw/pc_piix.c
>>>>> +++ b/hw/pc_piix.c
>>>>> @@ -46,6 +46,9 @@
>>>>>  #ifdef CONFIG_XEN
>>>>>  #  include <xen/hvm/hvm_info_table.h>
>>>>>  #endif
>>>>> +#ifdef CONFIG_KVM
>>>>> +#   include <asm/kvm_para.h>
>>>>> +#endif
>>>>>  
>>>>>  #define MAX_IDE_BUS 2
>>>>>  
>>>>> @@ -285,6 +288,12 @@ static void pc_init1(MemoryRegion *system_memory,
>>>>>      if (pci_enabled) {
>>>>>          pc_pci_device_init(pci_bus);
>>>>>      }
>>>>> +
>>>>> +#ifdef KVM_PV_EVENT_PORT
>>>>
>>>> This file is x86-only, and there we have KVM_PV_EVENT_PORT
>>>> unconditionally. So drop the #ifdef.
>>>>
>>>>> +    if (kvm_enabled()) {
>>>>> +        kvm_pv_event_init(isa_bus);
>>>>
>>>> But you are missing a kvm-stub entry for kvm_pv_event_init. A
>>>> --disable-kvm build should be broken for that reason.
>>>
>>> Hmm, KVM_PV_EVENT_PORT is defined in asm/kvm_para.h, and I include
>>> this file only when CONFIG_KVM is defined. So --disable-kvm build
>>> does not be broken in my test.
>>
>> Yeah, but that is a bit ugly and another reason to go for a proper kvm-stub.
> 
> Yes, it is ugly. I will add a stub function in kvm-stub. And the header
> file asm/kvm_para.h can be included unconditionally. And "#ifdef KVM_PV_EVENT_PORT"
> can be dropped.

Actually, not asm/kvm_para.h but linux/kvm_para.h. And you will then
only need it in pv_event.c.

Jan



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