On Thu, Sep 10, 2020 at 05:29:25PM +0200, Philippe Mathieu-Daudé wrote: > Hi Stefan, Alex. > > On 9/10/20 12:44 PM, Stefan Hajnoczi wrote: > > On Wed, Sep 09, 2020 at 04:23:53PM +0200, Philippe Mathieu-Daudé wrote: > >> +/** > >> + * Initialize device MSIX IRQs and register event notifiers. > >> + * @irq_count: pointer to number of MSIX IRQs to initialize > >> + * @notifier: Array of @irq_count notifiers (each corresponding to a MSIX > >> IRQ) > >> + > >> + * If the number of IRQs requested exceeds the available on the device, > >> + * store the number of available IRQs in @irq_count and return -EOVERFLOW. > >> + */ > >> +int qemu_vfio_pci_init_msix_irqs(QEMUVFIOState *s, EventNotifier > >> *notifier, > >> + unsigned *irq_count, Error **errp) > >> +{ > >> + int r; > >> + size_t irq_set_size; > >> + struct vfio_irq_set *irq_set; > >> + struct vfio_irq_info irq_info = { > >> + .argsz = sizeof(irq_info), > >> + .index = VFIO_PCI_MSIX_IRQ_INDEX > >> + }; > >> + > >> + if (ioctl(s->device, VFIO_DEVICE_GET_IRQ_INFO, &irq_info)) { > >> + error_setg_errno(errp, errno, "Failed to get device interrupt > >> info"); > >> + return -errno; > >> + } > >> + if (irq_info.count < *irq_count) { > >> + error_setg(errp, "Not enough device interrupts available"); > >> + *irq_count = irq_info.count; > >> + return -EOVERFLOW; > >> + } > >> + if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) { > >> + error_setg(errp, "Device interrupt doesn't support eventfd"); > >> + return -EINVAL; > >> + } > >> + > >> + irq_set_size = sizeof(*irq_set) + *irq_count * sizeof(int32_t); > >> + irq_set = g_malloc0(irq_set_size); > >> + > >> + /* Get to a known IRQ state */ > >> + *irq_set = (struct vfio_irq_set) { > >> + .argsz = irq_set_size, > >> + .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER, > >> + .index = irq_info.index, > >> + .start = 0, > >> + .count = *irq_count, > >> + }; > >> + > >> + for (unsigned i = 0; i < *irq_count; i++) { > >> + ((int32_t *)&irq_set->data)[i] = > >> event_notifier_get_fd(¬ifier[i]); > >> + } > >> + r = ioctl(s->device, VFIO_DEVICE_SET_IRQS, irq_set); > >> + g_free(irq_set); > >> + if (r <= 0) { > >> + error_setg_errno(errp, errno, "Failed to setup device > >> interrupts"); > >> + return -errno; > >> + } else if (r < *irq_count) { > >> + error_setg(errp, "Not enough device interrupts available"); > >> + *irq_count = r; > >> + return -EOVERFLOW; > >> + } > > > > EOVERFLOW can occur in two cases: VFIO_DEVICE_GET_IRQ_INFO and > > VFIO_DEVICE_SET_IRQS. > > Yes. > > > > > If it happens in the second case the notifier[] array has been > > registered successfully. > > No, I don't think so: > > vfio_pci_set_msi_trigger() register the notifier only if > vfio_msi_enable() succeeded (returned 0). If vfio_msi_enable() > failed it returns the number of vectors available but do > not register the notifiers.
Good, thanks! Stefan
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