From: Alex Bennée Date: Tue, 2 Aug 2022 09:49:56 +0000 (+0100) Subject: hw/virtio: log potentially buggy guest drivers X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8d11c10d0699d9ee9745b4b5bc138e573d852c0f;p=qemu.git hw/virtio: log potentially buggy guest drivers If the guest driver attempts to use the UNUSED(30) bit it is potentially buggy as 6.3 Legacy Interface: Reserved Feature Bits states it "SHOULD NOT be negotiated". For now just log this guest error. Signed-off-by: Alex Bennée Acked-by: Jason Wang Message-Id: <20220802095010.3330793-9-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 5d607aeaa0..97a6307c0f 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2980,6 +2980,13 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val) if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) { return -EINVAL; } + + if (val & (1ull << VIRTIO_F_BAD_FEATURE)) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: guest driver for %s has enabled UNUSED(30) feature bit!\n", + __func__, vdev->name); + } + ret = virtio_set_features_nocheck(vdev, val); if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */