Re: [Qemu-devel] [PATCH v14 3/4] introduce pvevent device to deal with panicked event

[Markus Armbruster]

Hu Tao <address@hidden> writes:

> pvevent device is used to send guest panic event from guest to qemu.
>
> When guest panic happens, pvevent device driver will write a event
> number to IO port 0x505(which is the IO port occupied by pvevent device,
> by default). On receiving the event, pvevent device will pause guest
> cpu(s), and send a qmp event QEVENT_GUEST_PANICKED.  
>
> TODO: make the IO port configurable
>
> Signed-off-by: Wen Congyang <address@hidden>
> Signed-off-by: Hu Tao <address@hidden>
> ---
>  hw/Makefile.objs |   2 +
>  hw/pvevent.c     | 116 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 118 insertions(+)
>  create mode 100644 hw/pvevent.c
>
> diff --git a/hw/Makefile.objs b/hw/Makefile.objs
> index 40ebe46..edf499e 100644
> --- a/hw/Makefile.objs
> +++ b/hw/Makefile.objs
> @@ -218,5 +218,7 @@ obj-$(CONFIG_KVM) += ivshmem.o
>  obj-$(CONFIG_LINUX) += vfio_pci.o
>  endif
>  
> +common-obj-y += pvevent.o
> +
>  $(obj)/baum.o: QEMU_CFLAGS += $(SDL_CFLAGS) 
>  endif
> diff --git a/hw/pvevent.c b/hw/pvevent.c
> new file mode 100644
> index 0000000..c7df77b
> --- /dev/null
> +++ b/hw/pvevent.c
> @@ -0,0 +1,116 @@
> +/*
> + * QEMU simulated pvevent device.
> + *
> + * Copyright Fujitsu, Corp. 2013
> + *
> + * Authors:
> + *     Wen Congyang <address@hidden>
> + *     Hu Tao <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 <qapi/qmp/qobject.h>
> +#include <qapi/qmp/qjson.h>
> +#include <monitor/monitor.h>
> +#include <sysemu/sysemu.h>
> +#include <sysemu/kvm.h>
> +
> +/* The bit of supported pv event */
> +#define PVEVENT_F_PANICKED      0
> +
> +/* The pv event value */
> +#define PVEVENT_PANICKED        (1 << PVEVENT_F_PANICKED)

This looks like events are encoded as bits, which can be combined into a
set, but...

> +
> +#define TYPE_ISA_PVEVENT_DEVICE    "pvevent"
> +#define ISA_PVEVENT_DEVICE(obj)    \
> +    OBJECT_CHECK(PVEventState, (obj), TYPE_ISA_PVEVENT_DEVICE)
> +
> +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 handle_event(int event)
> +{
> +    if (event == PVEVENT_PANICKED) {

... here you don't test bits.  Weird.  Intentional?

> +        panicked_mon_event("pause");
> +        vm_stop(RUN_STATE_GUEST_PANICKED);
> +        return;
> +    }
> +}

Should we log events we don't understand?

> +
> +#include "hw/isa.h"
> +
> +typedef struct PVEventState {
> +    ISADevice parent_obj;
> +
> +    MemoryRegion io;
> +    uint16_t ioport;
> +} PVEventState;
> +
> +/* return supported events on read */
> +static uint64_t pvevent_ioport_read(void *opaque, hwaddr addr, unsigned size)
> +{
> +    return PVEVENT_PANICKED;
> +}
> +
> +static void pvevent_ioport_write(void *opaque, hwaddr addr, uint64_t val,
> +                                 unsigned size)
> +{
> +    handle_event(val);
> +}
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