Improve error reporting when virtqueue ring mapping fails by including a device identifier in the error message.
Introduce a helper virtio_get_pretty_dev_name() that returns either: - the device ID, if explicitly provided (e.g. -device ...,id=foo) - the QOM path from qdev_get_dev_path(dev) otherwise - "<unknown device>" as a fallback when no identifier is present This makes it easier to identify which device triggered the error in multi-device setups or when debugging complex guest configurations. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/230 Buglink: https://bugs.launchpad.net/qemu/+bug/1919021 Suggested-by: Markus Armbruster <arm...@redhat.com> Signed-off-by: Alessandro Ratti <alessan...@0x65c.net> --- hw/virtio/virtio.c | 46 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 43 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 9a81ad912e..f5adc381a4 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -235,6 +235,37 @@ static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq) } } +static const char *virtio_get_pretty_dev_name(VirtIODevice *vdev) +{ + DeviceState *dev = DEVICE(vdev); + + /* + * Return device ID if explicity set + * (e.g. -device virtio-blk-pci,id=foo) + * This allows users to correlate errors with their custom device + * names. + */ + if (dev->id) { + return dev->id; + } + /* + * Fall back to the canonical QOM device path (eg. ID for PCI + * devices). + * This ensures the device is still uniquely and meaningfully + * identified. + */ + const char *path = qdev_get_dev_path(dev); + if (path) { + return path; + } + + /* + * Final fallback: if all else fails, return a placeholder string. + * This ensures the error message always contains a valid string. + */ + return "<unknow device>"; +} + void virtio_init_region_cache(VirtIODevice *vdev, int n) { VirtQueue *vq = &vdev->vq[n]; @@ -256,7 +287,10 @@ void virtio_init_region_cache(VirtIODevice *vdev, int n) len = address_space_cache_init(&new->desc, vdev->dma_as, addr, size, packed); if (len < size) { - virtio_error(vdev, "Cannot map desc"); + virtio_error(vdev, + "Failed to map descriptor ring for device %s: " + "invalid guest physical address or corrupted queue setup", + virtio_get_pretty_dev_name(vdev)); goto err_desc; } @@ -264,7 +298,10 @@ void virtio_init_region_cache(VirtIODevice *vdev, int n) len = address_space_cache_init(&new->used, vdev->dma_as, vq->vring.used, size, true); if (len < size) { - virtio_error(vdev, "Cannot map used"); + virtio_error(vdev, + "Failed to map used ring for device %s: " + "possible guest misconfiguration or insufficient memory", + virtio_get_pretty_dev_name(vdev)); goto err_used; } @@ -272,7 +309,10 @@ void virtio_init_region_cache(VirtIODevice *vdev, int n) len = address_space_cache_init(&new->avail, vdev->dma_as, vq->vring.avail, size, false); if (len < size) { - virtio_error(vdev, "Cannot map avail"); + virtio_error(vdev, + "Failed to map avalaible ring for device %s: " + "possible queue misconfiguration or overlapping memory region", + virtio_get_pretty_dev_name(vdev)); goto err_avail; } -- 2.39.5
