On 7/18/25 3:01 PM, Stefano Garzarella wrote:
> On Fri, Jul 18, 2025 at 10:52:36AM +0200, Paolo Abeni wrote:
>> @@ -234,7 +234,8 @@ struct vhost_net *vhost_net_init(VhostNetOptions
>> *options)
>> int r;
>> bool backend_kernel = options->backend_type == VHOST_BACKEND_TYPE_KERNEL;
>> struct vhost_net *net = g_new0(struct vhost_net, 1);
>> - uint64_t features = 0;
>> + uint64_t missing_features[VIRTIO_FEATURES_DWORDS];
>> + uint64_t features[VIRTIO_FEATURES_DWORDS];
>
> Should we initialize `features` (IIUC calling virtio_features_clear)
> since it was set to 0 before this patch?
>
>> Error *local_err = NULL;
>>
>> if (!options->net_backend) {
>> @@ -261,7 +262,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions
>> *options)
>> net->backend = r;
>> net->dev.protocol_features = 0;
>> } else {
>> - net->dev.backend_features = 0;
>> + virtio_features_clear(net->dev.backend_features_ex);
>> net->dev.protocol_features = 0;
>> net->backend = -1;
>>
>> @@ -279,28 +280,31 @@ struct vhost_net *vhost_net_init(VhostNetOptions
>> *options)
>> if (backend_kernel) {
>> if (!qemu_has_vnet_hdr_len(options->net_backend,
>> sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
>> - net->dev.features &= ~(1ULL << VIRTIO_NET_F_MRG_RXBUF);
>> + net->dev.features &= ~VIRTIO_BIT(VIRTIO_NET_F_MRG_RXBUF);
>> }
>> - if (~net->dev.features & net->dev.backend_features) {
>> - fprintf(stderr, "vhost lacks feature mask 0x%" PRIx64
>> - " for backend\n",
>> - (uint64_t)(~net->dev.features &
>> net->dev.backend_features));
>> +
>> + if (virtio_features_andnot(missing_features,
>> + net->dev.backend_features_ex,
>> + net->dev.features_ex)) {
>> + fprintf(stderr, "vhost lacks feature mask 0x"
>> VIRTIO_FEATURES_FMT
>> + " for backend\n", VIRTIO_FEATURES_PR(missing_features));
>> goto fail;
>> }
>> }
>>
>> /* Set sane init value. Override when guest acks. */
>> if (options->get_acked_features) {
>> - features = options->get_acked_features(net->nc);
>> - if (~net->dev.features & features) {
>> - fprintf(stderr, "vhost lacks feature mask 0x%" PRIx64
>> - " for backend\n",
>> - (uint64_t)(~net->dev.features & features));
>> + virtio_features_from_u64(features,
>> + options->get_acked_features(net->nc));
>> + if (virtio_features_andnot(missing_features, features,
>> + net->dev.features_ex)) {
>> + fprintf(stderr, "vhost lacks feature mask 0x"
>> VIRTIO_FEATURES_FMT
>> + " for backend\n", VIRTIO_FEATURES_PR(missing_features));
>> goto fail;
>> }
>> }
>>
>> - vhost_net_ack_features(net, features);
>> + vhost_net_ack_features_ex(net, features);
>
> If `options->get_acked_features` is false, `features` here is not
> initialized (it was set to 0 before this patch).
Indeed the initialization is needed. I will fix the next revision.
Thanks,
Paolo
