Hi, On 5/15/19 12:01 PM, Li Qiang wrote: > Hello Paolo, Alex and all, > > In vfio_intx_enable_kvm(qemu) I see we associate a resamplefd with the > umask function(vfio_pci_intx_unmask_handler in linux). > > irq_set = g_malloc0(argsz); > irq_set->argsz = argsz; > irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK; > irq_set->index = VFIO_PCI_INTX_IRQ_INDEX; > irq_set->start = 0; > irq_set->count = 1; > pfd = (int32_t *)&irq_set->data; > > *pfd = irqfd.resamplefd; > > ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set); > > I know this resamplefd is triggered when the interrupt controller receives > an EOI and > then we unmask and re-enabled the VFIO devices' interrupt. > > So I think there there must be a mask process(so we unmask it later), I > mean there must a > call of function vfio_pci_set_intx_mask(in linux). > > What I can't understand is when this process(mask VFIO devices' interrupt) > occurs? It is done in the VFIO interrupt handler: vfio_intx_handler/disable_irq_nosync for VFIO PCI (vfio_pci_intrs.c) or vfio_automasked_irq_handler (vfio_platform_irq.c) for VFIO PLATFORM .
Thanks Eric > I only find a place(vfio_basic_config_write) calls vfio_pci_intx_mask> I > think when the guest process the interrupt it may mask this > interrupt(finally call vfio_pci_set_intx_mask), but I can't find the code > path related with vfio_basic_config_write. > > > Any hints? > > Thanks, > Li Qiang >
