From 3b11003fa67b3f055637ff52e1fe8327f7590ee1 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 22 Sep 2025 18:01:47 -0400 Subject: [PATCH] virtio: support irqfd in virtio_notify_config() virtio_error() calls virtio_notify_config() to inject a VIRTIO Configuration Change Notification. This doesn't work from IOThreads because the BQL is not held and the interrupt code path requires the BQL. Follow the same approach as virtio_notify() and use ->config_notifier (an irqfd) when called from the IOThread. Signed-off-by: Stefan Hajnoczi Reviewed-by: Michael S. Tsirkin Message-ID: <20250922220149.498967-4-stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 6ce5823898..de89e8104a 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2706,7 +2706,12 @@ void virtio_notify_config(VirtIODevice *vdev) virtio_set_isr(vdev, 0x3); vdev->generation++; - virtio_notify_vector(vdev, vdev->config_vector); + + if (qemu_in_iothread()) { + defer_call(virtio_notify_irqfd_deferred_fn, &vdev->config_notifier); + } else { + virtio_notify_vector(vdev, vdev->config_vector); + } } static bool virtio_device_endian_needed(void *opaque) -- 2.47.3