On Wed, 19 Aug 2020 18:03:17 +0200 Philippe Mathieu-Daudé <[email protected]> wrote:
> qemu_vfio_pci_init_irq() allows us to initialize any type of IRQ, > but only one. Introduce qemu_vfio_pci_init_msix_irqs() which is > specific to MSIX IRQ type, and allow us to use multiple IRQs > (thus passing multiple eventfd notifiers). > > Signed-off-by: Philippe Mathieu-Daudé <[email protected]> > --- > include/qemu/vfio-helpers.h | 2 ++ > util/vfio-helpers.c | 57 +++++++++++++++++++++++++++++++++++++ > 2 files changed, 59 insertions(+) > > diff --git a/include/qemu/vfio-helpers.h b/include/qemu/vfio-helpers.h > index 1f057c2b9e4..8e6bd83ea41 100644 > --- a/include/qemu/vfio-helpers.h > +++ b/include/qemu/vfio-helpers.h > @@ -28,5 +28,7 @@ void qemu_vfio_pci_unmap_bar(QEMUVFIOState *s, int index, > void *bar, > uint64_t offset, uint64_t size); > int qemu_vfio_pci_init_irq(QEMUVFIOState *s, EventNotifier *e, > int irq_type, Error **errp); > +int qemu_vfio_pci_init_msix_irqs(QEMUVFIOState *s, EventNotifier *e, > + unsigned *irq_count, Error **errp); > > #endif > diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c > index 8f4a3d452ed..6f833972587 100644 > --- a/util/vfio-helpers.c > +++ b/util/vfio-helpers.c > @@ -216,6 +216,63 @@ int qemu_vfio_pci_init_irq(QEMUVFIOState *s, > EventNotifier *e, > return 0; > } > > +/** > + * 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) { > + error_setg_errno(errp, errno, "Failed to setup device interrupts"); > + return -errno; FWIW, the former irq_info.count check returns what the device is capable of, the platform might only have limited vector space available, therefore this ioctl can also return a value indicating the number of vectors \actually\ available. So if r > 0 you could return it in *irq_count (which also makes me wonder if errno would be set in that case). Thanks, Alex > + } > + return 0; > +} > + > static int qemu_vfio_pci_read_config(QEMUVFIOState *s, void *buf, > int size, int ofs) > {
