Re: [PATCH 0/2] irq: add get_gsi callback

Eric Auger
2015-04-24T09:42:37Z

On 04/24/2015 11:29 AM, Paolo Bonzini wrote:
>
>
> On 24/04/2015 11:18, Eric Auger wrote:
>>>>>> I implemented this alternative but my concern is the check method is
>>>>>> called before the qemu_irq setting. So on this callback I cannot
>>>>>> retrieve the qemu_irq VFIOINTp struct container object needed to setup
>>>>>> irqfd hence does not work for me.
>>>>
>>>> Isn't the qemu_irq passed as the third argument to the callback? I
>>>> thought this solution was fine because you weren't passing the "int n"
>>>> from sysbus_connect_irq to your notifier.
>> Yes it is. But I need to access the EventNotifiers for trigger &
>> resample which were initialized before for eventfd trigger and stored in
>> the container object. Will study if I can restructure the code ...
>
> What did the notifier code look like with your patch?

Currently both notifiers are stored in the VFIOINTp struct. They are
initialized in vfio_init_intp. VFIO platform device holds a list of
VFIOINTp struct.

When the vfio_start_irqfd callback is called the qemuirq is not yet
initialized so I cannot retrieve the EventNotifiers by container_of.

I can allocate and initialize them in the callback but I need a place to
store them to close the eventfd.

Also at the moment I start irqfd I must take some actions to stop (user
side) eventfd trigger; this also urges me to get access to VFIOINTp
struct. Some extracted pieces below (under work).

Eric

typedef struct VFIOINTp {
QLIST_ENTRY(VFIOINTp) next; /* entry for IRQ list */
QSIMPLEQ_ENTRY(VFIOINTp) pqnext; /* entry for pending IRQ queue */
EventNotifier interrupt; /* eventfd triggered on interrupt */
EventNotifier unmask; /* eventfd for unmask on QEMU bypass */
qemu_irq qemuirq;
struct VFIOPlatformDevice *vdev; /* back pointer to device */
int state; /* inactive, pending, active */
uint8_t pin; /* index */
uint32_t flags; /* IRQ info flags */
bool kvm_accel; /* set when QEMU bypass through KVM enabled */
} VFIOINTp;

static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev,
struct vfio_irq_info info)
{
int ret;
VFIOPlatformDevice *vdev =
container_of(vbasedev, VFIOPlatformDevice, vbasedev);
SysBusDevice *sbdev = SYS_BUS_DEVICE(vdev);
VFIOINTp *intp;

intp = g_malloc0(sizeof(*intp));
intp->vdev = vdev;
intp->pin = info.index;
intp->flags = info.flags;
intp->state = VFIO_IRQ_INACTIVE;
intp->kvm_accel = false;

sysbus_init_irq(sbdev, &intp->qemuirq);

/* Get an eventfd for trigger */
ret = event_notifier_init(&intp->interrupt, 0);
if (ret) {
g_free(intp);
error_report("vfio: Error: trigger event_notifier_init failed ");
return NULL;
}
/* Get an eventfd for resample/unmask */
ret = event_notifier_init(&intp->unmask, 0);
if (ret) {
g_free(intp);
error_report("vfio: Error: resample event_notifier_init failed ");
return NULL;
}

static void vfio_start_irqfd(Object *obj, const char *name,
Object *child, Error ** err)
{
VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(obj);
qemu_irq irq = OBJECT_CHECK(struct IRQState, (child), TYPE_IRQ);
struct VFIOINTp *tmp, *intp = container_of(&irq, struct VFIOINTp,
qemuirq);
EventNotifier *interrupt, *unmask;

vfio_stop_vfio_signaling(intp);

interrupt = g_new(EventNotifier, 1);
unmask = g_new(EventNotifier, 1);

/* Get an eventfd for trigger */
ret = event_notifier_init(interrupt, 0);
if (ret) {
return NULL;
}
/* Get an eventfd for resample/unmask */
ret = event_notifier_init(unmask, 0);
if (ret) {
return NULL;
}

kvm_irqchip_add_qemuirq_irqfd_notifier(kvm_state,
interrupt,
unmask,
irq);

../..
}

>
> Paolo
>