vfio-ccw resorts to the eventfd mechanism to communicate with userspace. We fetch the irqs info via the ioctl VFIO_DEVICE_GET_IRQ_INFO, register a event notifier to get the eventfd fd which is sent to kernel via the ioctl VFIO_DEVICE_SET_IRQS, then we can implement read operation once kernel sends the signal.
Reviewed-by: Eric Auger <eric.au...@redhat.com> Acked-by: Alex Williamson <alex.william...@redhat.com> Signed-off-by: Dong Jia Shi <bjsdj...@linux.vnet.ibm.com> --- hw/vfio/ccw.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 7ddcfd7767..689a7724b6 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -22,6 +22,7 @@ #include "hw/vfio/vfio-common.h" #include "hw/s390x/s390-ccw.h" #include "hw/s390x/ccw-device.h" +#include "qemu/error-report.h" #define TYPE_VFIO_CCW "vfio-ccw" typedef struct VFIOCCWDevice { @@ -30,6 +31,7 @@ typedef struct VFIOCCWDevice { uint64_t io_region_size; uint64_t io_region_offset; struct ccw_io_region *io_region; + EventNotifier io_notifier; } VFIOCCWDevice; static void vfio_ccw_compute_needs_reset(VFIODevice *vdev) @@ -54,6 +56,97 @@ static void vfio_ccw_reset(DeviceState *dev) ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET); } +static void vfio_ccw_io_notifier_handler(void *opaque) +{ + VFIOCCWDevice *vcdev = opaque; + + if (!event_notifier_test_and_clear(&vcdev->io_notifier)) { + return; + } +} + +static void vfio_ccw_register_io_notifier(VFIOCCWDevice *vcdev, Error **errp) +{ + VFIODevice *vdev = &vcdev->vdev; + struct vfio_irq_info *irq_info; + struct vfio_irq_set *irq_set; + size_t argsz; + int32_t *pfd; + + if (vdev->num_irqs < VFIO_CCW_IO_IRQ_INDEX + 1) { + error_setg(errp, "vfio: unexpected number of io irqs %u", + vdev->num_irqs); + return; + } + + argsz = sizeof(*irq_set); + irq_info = g_malloc0(argsz); + irq_info->index = VFIO_CCW_IO_IRQ_INDEX; + irq_info->argsz = argsz; + if (ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO, + irq_info) < 0 || irq_info->count < 1) { + error_setg_errno(errp, errno, "vfio: Error getting irq info"); + goto out_free_info; + } + + if (event_notifier_init(&vcdev->io_notifier, 0)) { + error_setg_errno(errp, errno, + "vfio: Unable to init event notifier for IO"); + goto out_free_info; + } + + argsz = sizeof(*irq_set) + sizeof(*pfd); + irq_set = g_malloc0(argsz); + irq_set->argsz = argsz; + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | + VFIO_IRQ_SET_ACTION_TRIGGER; + irq_set->index = VFIO_CCW_IO_IRQ_INDEX; + irq_set->start = 0; + irq_set->count = 1; + pfd = (int32_t *) &irq_set->data; + + *pfd = event_notifier_get_fd(&vcdev->io_notifier); + qemu_set_fd_handler(*pfd, vfio_ccw_io_notifier_handler, NULL, vcdev); + if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) { + error_setg(errp, "vfio: Failed to set up io notification"); + qemu_set_fd_handler(*pfd, NULL, NULL, vcdev); + event_notifier_cleanup(&vcdev->io_notifier); + } + + g_free(irq_set); + +out_free_info: + g_free(irq_info); +} + +static void vfio_ccw_unregister_io_notifier(VFIOCCWDevice *vcdev) +{ + struct vfio_irq_set *irq_set; + size_t argsz; + int32_t *pfd; + + argsz = sizeof(*irq_set) + sizeof(*pfd); + irq_set = g_malloc0(argsz); + irq_set->argsz = argsz; + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | + VFIO_IRQ_SET_ACTION_TRIGGER; + irq_set->index = VFIO_CCW_IO_IRQ_INDEX; + irq_set->start = 0; + irq_set->count = 1; + pfd = (int32_t *) &irq_set->data; + *pfd = -1; + + if (ioctl(vcdev->vdev.fd, VFIO_DEVICE_SET_IRQS, irq_set)) { + error_report("vfio: Failed to de-assign device io fd: %m"); + } + + qemu_set_fd_handler(event_notifier_get_fd(&vcdev->io_notifier), + NULL, NULL, vcdev); + event_notifier_cleanup(&vcdev->io_notifier); + + g_free(irq_set); +} + static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp) { VFIODevice *vdev = &vcdev->vdev; @@ -173,8 +266,15 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp) goto out_region_err; } + vfio_ccw_register_io_notifier(vcdev, &err); + if (err) { + goto out_notifier_err; + } + return; +out_notifier_err: + vfio_ccw_put_region(vcdev); out_region_err: vfio_put_device(vcdev); out_device_err: @@ -195,6 +295,7 @@ static void vfio_ccw_unrealize(DeviceState *dev, Error **errp) S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev); VFIOGroup *group = vcdev->vdev.group; + vfio_ccw_unregister_io_notifier(vcdev); vfio_ccw_put_region(vcdev); vfio_put_device(vcdev); vfio_put_group(group); -- 2.11.2