Re: [Qemu-devel] [PATCH 5/6 v5] deal with guest panicked event accoring to -onpanic parameter

[Wen Congyang <wency@cn.fujitsu.com>]

At 06/28/2012 04:26 PM, Jan Kiszka Wrote:
> On 2012-06-28 03:15, Wen Congyang wrote:
>> At 06/27/2012 10:39 PM, Jan Kiszka Wrote:
>>> On 2012-06-27 09:02, Wen Congyang wrote:
>>>> When the guest is panicked, it will write 0x1 to the port KVM_PV_PORT.
>>>> So if qemu reads 0x1 from this port, we can do the folloing three
>>>> things according to the parameter -onpanic:
>>>> 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
>>>>
>>>> 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>
>>>> ---
>>>>  kvm-all.c       |  101 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>  kvm-stub.c      |    9 +++++
>>>>  kvm.h           |    3 ++
>>>>  qemu-options.hx |   15 ++++++++
>>>>  vl.c            |   10 +++++
>>>>  5 files changed, 138 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/kvm-all.c b/kvm-all.c
>>>> index f8e4328..9494dd2 100644
>>>> --- a/kvm-all.c
>>>> +++ b/kvm-all.c
>>>> @@ -19,6 +19,8 @@
>>>>  #include <stdarg.h>
>>>>  
>>>>  #include <linux/kvm.h>
>>>> +#include <linux/kvm_para.h>
>>>> +#include <asm/kvm_para.h>
>>>>  
>>>>  #include "qemu-common.h"
>>>>  #include "qemu-barrier.h"
>>>> @@ -32,6 +34,9 @@
>>>>  #include "bswap.h"
>>>>  #include "memory.h"
>>>>  #include "exec-memory.h"
>>>> +#include "iorange.h"
>>>> +#include "qemu-objects.h"
>>>> +#include "monitor.h"
>>>>  
>>>>  /* This check must be after config-host.h is included */
>>>>  #ifdef CONFIG_EVENTFD
>>>> @@ -1931,3 +1936,99 @@ int kvm_on_sigbus(int code, void *addr)
>>>>  {
>>>>      return kvm_arch_on_sigbus(code, addr);
>>>>  }
>>>> +
>>>> +/* 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;
>>>> +
>>>> +static void kvm_pv_port_read(IORange *iorange, uint64_t offset, unsigned width,
>>>> +                             uint64_t *data)
>>>> +{
>>>> +    *data = (1 << KVM_PV_FEATURE_PANICKED);
>>>> +}
>>>> +
>>>> +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(void)
>>>> +{
>>>> +    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");
>>>> +        exit(0);
>>>> +        break;
>>>> +    case PANICKED_RESET:
>>>> +        panicked_mon_event("reset");
>>>> +        qemu_system_reset_request();
>>>> +        break;
>>>> +    }
>>>> +}
>>>> +
>>>> +static void kvm_pv_port_write(IORange *iorange, uint64_t offset, unsigned width,
>>>> +                              uint64_t data)
>>>> +{
>>>> +    if (data == KVM_PV_PANICKED) {
>>>> +        panicked_perform_action();
>>>> +    }
>>>> +}
>>>> +
>>>> +static void kvm_pv_port_destructor(IORange *iorange)
>>>> +{
>>>> +    g_free(iorange);
>>>> +}
>>>> +
>>>> +static IORangeOps pv_io_range_ops = {
>>>> +    .read = kvm_pv_port_read,
>>>> +    .write = kvm_pv_port_write,
>>>> +    .destructor = kvm_pv_port_destructor,
>>>> +};
>>>> +
>>>> +#if defined(KVM_PV_PORT)
>>>> +void kvm_pv_port_init(void)
>>>> +{
>>>> +    IORange *pv_io_range = g_malloc(sizeof(IORange));
>>>> +
>>>> +    iorange_init(pv_io_range, &pv_io_range_ops, KVM_PV_PORT, 1);
>>>> +    ioport_register(pv_io_range);
>>>
>>> This modeling is still not ok. We don't open-code ports anymore, we
>>> introduce devices. And this doesn't belong inro generic code as it is
>>
>> Do you mean introducing a new device instead of I/O port?
> 
> I mean encapsulating the I/O registration (PIO or MMIO) in a QOM device

A QOM device? Do you mean introduce a new device? If so, the guest should
have a driver to know such device. Another problem is: we cannot use
such device when the kernel is starting(the device's driver is not ready).
If we use a new device, I think virtio-serial is enough. The reason why
I do not use virtio-serial is: I want the feature can also work when the
kernel is starting.

Thanks
Wen Congyang
> and building that device only for target archs that supports it. Already
> pointed you to examples in hw/kvm/.
> 
> Jan
>