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

[Wen Congyang]

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 <address@hidden>
>>>> ---
>>>>  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 <address@hidden>
>>>> + *
>>>> + * 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.

Thanks
Wen Congyang

> 
> Jan
> 
>