diff options
Diffstat (limited to 'lib/libvirtio/virtio.c')
| -rw-r--r-- | lib/libvirtio/virtio.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c index ba7aced..276d69f 100644 --- a/lib/libvirtio/virtio.c +++ b/lib/libvirtio/virtio.c @@ -297,6 +297,18 @@ void virtio_set_status(struct virtio_device *dev, int status) } } +/** + * Get device status bits + */ +void virtio_get_status(struct virtio_device *dev, int *status) +{ + if (dev->is_modern) { + *status = ci_read_8(dev->common.addr + + offset_of(struct virtio_dev_common, dev_status)); + } else { + *status = ci_read_8(dev->base+VIRTIOHDR_DEVICE_STATUS); + } +} /** * Set guest feature bits @@ -350,6 +362,36 @@ uint64_t virtio_get_host_features(struct virtio_device *dev) return features; } +int virtio_negotiate_guest_features(struct virtio_device *dev, uint64_t features) +{ + uint64_t host_features = 0; + int status; + + /* Negotiate features */ + host_features = virtio_get_host_features(dev); + if (!(host_features & VIRTIO_F_VERSION_1)) { + fprintf(stderr, "Device does not support virtio 1.0 %llx\n", host_features); + return -1; + } + + virtio_set_guest_features(dev, features); + host_features = virtio_get_host_features(dev); + if ((host_features & features) != features) { + fprintf(stderr, "Features error %llx\n", features); + return -1; + } + + virtio_get_status(dev, &status); + status |= VIRTIO_STAT_FEATURES_OK; + virtio_set_status(dev, status); + + /* Read back to verify the FEATURES_OK bit */ + virtio_get_status(dev, &status); + if ((status & VIRTIO_STAT_FEATURES_OK) != VIRTIO_STAT_FEATURES_OK) + return -1; + + return 0; +} /** * Get additional config values |