Question:
How will libvirt (as an example) work with this change. In the
existing semantic of libvirt profile the "on" means "on if possible"
and using existing profile after qemu update will still use "on" with
meaning "force"?
Typically this is solved by machine type - if libvirt uses
'machine='pc-q35-8.1'' this will be backward-compatible.
How will this change be accepted?
On Sun, Apr 28, 2024 at 10:21 AM Akihiko Odaki <akihiko.od...@daynix.com> wrote:
>
> Some features are not always available, and virtio-net used to disable
> them when not available even if the corresponding properties were
> explicitly set to "on".
>
> Convert feature properties to OnOffAuto so that the user can explicitly
> tell QEMU to automatically select the value by setting them "auto".
> QEMU will give an error if they are set "on".
>
> Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
> ---
> include/hw/virtio/virtio-net.h | 2 +-
> hw/net/virtio-net.c | 247
> +++++++++++++++++++++++++----------------
> 2 files changed, 152 insertions(+), 97 deletions(-)
>
> diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
> index 060c23c04d2d..ff32e30f001b 100644
> --- a/include/hw/virtio/virtio-net.h
> +++ b/include/hw/virtio/virtio-net.h
> @@ -178,7 +178,7 @@ struct VirtIONet {
> uint32_t has_vnet_hdr;
> size_t host_hdr_len;
> size_t guest_hdr_len;
> - uint64_t host_features;
> + OnOffAutoBit64 host_features;
> uint32_t rsc_timeout;
> uint8_t rsc4_enabled;
> uint8_t rsc6_enabled;
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index c8059dc99bd4..5b6c901915a9 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -750,58 +750,96 @@ static void virtio_net_set_queue_pairs(VirtIONet *n)
>
> static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue);
>
> +static bool virtio_net_clear_features(OnOffAutoBit64 *features,
> + uint64_t clear_bits,
> + const char *reason, Error **errp)
> +{
> + if (features->on_bits & clear_bits) {
> + error_setg(errp, "%s", reason);
> + return false;
> + }
> +
> + features->auto_bits &= ~clear_bits;
> +
> + return true;
> +}
> +
> static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t
> features,
> Error **errp)
> {
> VirtIONet *n = VIRTIO_NET(vdev);
> NetClientState *nc = qemu_get_queue(n->nic);
> -
> - /* Firstly sync all virtio-net possible supported features */
> - features |= n->host_features;
> -
> - virtio_add_feature(&features, VIRTIO_NET_F_MAC);
> -
> - if (!peer_has_vnet_hdr(n)) {
> - virtio_clear_feature(&features, VIRTIO_NET_F_CSUM);
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_TSO4);
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_TSO6);
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_ECN);
> -
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_CSUM);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO4);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO6);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_ECN);
> -
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_USO);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_USO4);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_USO6);
> -
> - virtio_clear_feature(&features, VIRTIO_NET_F_HASH_REPORT);
> - }
> -
> - if (!peer_has_vnet_hdr(n) || !peer_has_ufo(n)) {
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_UFO);
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_UFO);
> - }
> -
> - if (!peer_has_uso(n)) {
> - virtio_clear_feature(&features, VIRTIO_NET_F_HOST_USO);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_USO4);
> - virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_USO6);
> + OnOffAutoBit64 on_off_auto_features = n->host_features;
> +
> + on_off_auto_features.on_bits |= features;
> + virtio_add_feature(&on_off_auto_features.auto_bits, VIRTIO_NET_F_MAC);
> +
> + if (!((peer_has_vnet_hdr(n) ||
> + virtio_net_clear_features(&on_off_auto_features,
> + BIT_ULL(VIRTIO_NET_F_CSUM) |
> + BIT_ULL(VIRTIO_NET_F_HOST_TSO4) |
> + BIT_ULL(VIRTIO_NET_F_HOST_TSO6) |
> + BIT_ULL(VIRTIO_NET_F_HOST_ECN) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_UFO) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_CSUM) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_TSO4) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_TSO6) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_ECN) |
> + BIT_ULL(VIRTIO_NET_F_HOST_UFO) |
> + BIT_ULL(VIRTIO_NET_F_HOST_USO) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_USO4) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_USO6) |
> + BIT_ULL(VIRTIO_NET_F_HASH_REPORT),
> + "A requested feature requires the peer
> to support virtio-net headers.",
> + errp)) &&
> + (peer_has_ufo(n) ||
> + virtio_net_clear_features(&on_off_auto_features,
> + BIT_ULL(VIRTIO_NET_F_GUEST_UFO) |
> + BIT_ULL(VIRTIO_NET_F_HOST_UFO),
> + "UFO is on but the peer does not
> support it.",
> + errp)) &&
> + (peer_has_uso(n) ||
> + virtio_net_clear_features(&on_off_auto_features,
> + BIT_ULL(VIRTIO_NET_F_HOST_USO) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_USO4) |
> + BIT_ULL(VIRTIO_NET_F_GUEST_USO6),
> + "USO is on but the peer does not
> support it.",
> + errp)) &&
> + (virtio_has_feature(on_off_auto_features.on_bits |
> + on_off_auto_features.auto_bits,
> + VIRTIO_NET_F_CTRL_VQ) ||
> + virtio_net_clear_features(&on_off_auto_features,
> + BIT_ULL(VIRTIO_NET_F_GUEST_ANNOUNCE),
> + "guest_announce is on but ctrl_vq is
> off.",
> + errp)))) {
> + return 0;
> }
>
> if (!get_vhost_net(nc->peer)) {
> - return features;
> + if (!ebpf_rss_is_loaded(&n->ebpf_rss)) {
> + virtio_clear_feature(&on_off_auto_features.auto_bits,
> + VIRTIO_NET_F_RSS);
> + }
> +
> + return on_off_auto_features.on_bits | on_off_auto_features.auto_bits;
> }
>
> - if (!ebpf_rss_is_loaded(&n->ebpf_rss)) {
> - virtio_clear_feature(&features, VIRTIO_NET_F_RSS);
> + if (!ebpf_rss_is_loaded(&n->ebpf_rss) &&
> + !virtio_net_clear_features(&on_off_auto_features,
> + BIT_ULL(VIRTIO_NET_F_RSS),
> + "Both RSS and vhost are on but eBPF is
> unavailable; fix eBPF or disable RSS.",
> + errp)) {
> + return 0;
> }
> - features = vhost_net_get_features(get_vhost_net(nc->peer), features);
> + features = vhost_net_get_features(get_vhost_net(nc->peer),
> + on_off_auto_features.on_bits |
> + on_off_auto_features.auto_bits);
> vdev->backend_features = features;
>
> if (n->mtu_bypass_backend &&
> - (n->host_features & 1ULL << VIRTIO_NET_F_MTU)) {
> + virtio_has_feature(on_off_auto_features.on_bits |
> + on_off_auto_features.auto_bits,
> + VIRTIO_NET_F_MTU)) {
> features |= (1ULL << VIRTIO_NET_F_MTU);
> }
>
> @@ -820,6 +858,12 @@ static uint64_t virtio_net_get_features(VirtIODevice
> *vdev, uint64_t features,
> virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_ANNOUNCE);
> }
>
> + if ((features & on_off_auto_features.on_bits) !=
> + on_off_auto_features.on_bits) {
> + error_setg(errp, "A requested feature is incompatible with vhost.");
> + return 0;
> + }
> +
> return features;
> }
>
> @@ -3598,7 +3642,7 @@ static void virtio_net_device_realize(DeviceState *dev,
> Error **errp)
> int i;
>
> if (n->net_conf.mtu) {
> - n->host_features |= (1ULL << VIRTIO_NET_F_MTU);
> + n->host_features.on_bits |= (1ULL << VIRTIO_NET_F_MTU);
> }
>
> if (n->net_conf.duplex_str) {
> @@ -3610,7 +3654,7 @@ static void virtio_net_device_realize(DeviceState *dev,
> Error **errp)
> error_setg(errp, "'duplex' must be 'half' or 'full'");
> return;
> }
> - n->host_features |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> + n->host_features.on_bits |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> } else {
> n->net_conf.duplex = DUPLEX_UNKNOWN;
> }
> @@ -3620,7 +3664,7 @@ static void virtio_net_device_realize(DeviceState *dev,
> Error **errp)
> return;
> }
> if (n->net_conf.speed >= 0) {
> - n->host_features |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> + n->host_features.on_bits |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> }
>
> if (n->failover) {
> @@ -3629,10 +3673,12 @@ static void virtio_net_device_realize(DeviceState
> *dev, Error **errp)
> device_listener_register(&n->primary_listener);
> migration_add_notifier(&n->migration_state,
> virtio_net_migration_state_notifier);
> - n->host_features |= (1ULL << VIRTIO_NET_F_STANDBY);
> + n->host_features.on_bits |= (1ULL << VIRTIO_NET_F_STANDBY);
> }
>
> - virtio_net_set_config_size(n, n->host_features);
> + virtio_net_set_config_size(n,
> + n->host_features.on_bits |
> + n->host_features.auto_bits);
> virtio_init(vdev, VIRTIO_ID_NET, n->config_size);
>
> /*
> @@ -3759,7 +3805,9 @@ static void virtio_net_device_realize(DeviceState *dev,
> Error **errp)
>
> net_rx_pkt_init(&n->rx_pkt);
>
> - if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
> + if (virtio_has_feature(n->host_features.on_bits |
> + n->host_features.auto_bits,
> + VIRTIO_NET_F_RSS)) {
> virtio_net_load_ebpf(n);
> }
> }
> @@ -3770,7 +3818,9 @@ static void virtio_net_device_unrealize(DeviceState
> *dev)
> VirtIONet *n = VIRTIO_NET(dev);
> int i, max_queue_pairs;
>
> - if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
> + if (virtio_has_feature(n->host_features.on_bits |
> + n->host_features.auto_bits,
> + VIRTIO_NET_F_RSS)) {
> virtio_net_unload_ebpf(n);
> }
>
> @@ -3914,53 +3964,58 @@ static const VMStateDescription vmstate_virtio_net = {
> };
>
> static Property virtio_net_properties[] = {
> - DEFINE_PROP_BIT64("csum", VirtIONet, host_features,
> - VIRTIO_NET_F_CSUM, true),
> - DEFINE_PROP_BIT64("guest_csum", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_CSUM, true),
> - DEFINE_PROP_BIT64("gso", VirtIONet, host_features, VIRTIO_NET_F_GSO,
> true),
> - DEFINE_PROP_BIT64("guest_tso4", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_TSO4, true),
> - DEFINE_PROP_BIT64("guest_tso6", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_TSO6, true),
> - DEFINE_PROP_BIT64("guest_ecn", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_ECN, true),
> - DEFINE_PROP_BIT64("guest_ufo", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_UFO, true),
> - DEFINE_PROP_BIT64("guest_announce", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_ANNOUNCE, true),
> - DEFINE_PROP_BIT64("host_tso4", VirtIONet, host_features,
> - VIRTIO_NET_F_HOST_TSO4, true),
> - DEFINE_PROP_BIT64("host_tso6", VirtIONet, host_features,
> - VIRTIO_NET_F_HOST_TSO6, true),
> - DEFINE_PROP_BIT64("host_ecn", VirtIONet, host_features,
> - VIRTIO_NET_F_HOST_ECN, true),
> - DEFINE_PROP_BIT64("host_ufo", VirtIONet, host_features,
> - VIRTIO_NET_F_HOST_UFO, true),
> - DEFINE_PROP_BIT64("mrg_rxbuf", VirtIONet, host_features,
> - VIRTIO_NET_F_MRG_RXBUF, true),
> - DEFINE_PROP_BIT64("status", VirtIONet, host_features,
> - VIRTIO_NET_F_STATUS, true),
> - DEFINE_PROP_BIT64("ctrl_vq", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_VQ, true),
> - DEFINE_PROP_BIT64("ctrl_rx", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_RX, true),
> - DEFINE_PROP_BIT64("ctrl_vlan", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_VLAN, true),
> - DEFINE_PROP_BIT64("ctrl_rx_extra", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_RX_EXTRA, true),
> - DEFINE_PROP_BIT64("ctrl_mac_addr", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_MAC_ADDR, true),
> - DEFINE_PROP_BIT64("ctrl_guest_offloads", VirtIONet, host_features,
> - VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, true),
> - DEFINE_PROP_BIT64("mq", VirtIONet, host_features, VIRTIO_NET_F_MQ,
> false),
> - DEFINE_PROP_BIT64("rss", VirtIONet, host_features,
> - VIRTIO_NET_F_RSS, false),
> - DEFINE_PROP_BIT64("hash", VirtIONet, host_features,
> - VIRTIO_NET_F_HASH_REPORT, false),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("csum", VirtIONet, host_features,
> + VIRTIO_NET_F_CSUM, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_csum", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_CSUM, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("gso", VirtIONet, host_features,
> + VIRTIO_NET_F_GSO, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_tso4", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_TSO4, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_tso6", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_TSO6, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_ecn", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_ECN, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_ufo", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_UFO, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_announce", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_ANNOUNCE,
> + ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("host_tso4", VirtIONet, host_features,
> + VIRTIO_NET_F_HOST_TSO4, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("host_tso6", VirtIONet, host_features,
> + VIRTIO_NET_F_HOST_TSO6, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("host_ecn", VirtIONet, host_features,
> + VIRTIO_NET_F_HOST_ECN, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("host_ufo", VirtIONet, host_features,
> + VIRTIO_NET_F_HOST_UFO, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("mrg_rxbuf", VirtIONet, host_features,
> + VIRTIO_NET_F_MRG_RXBUF, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("status", VirtIONet, host_features,
> + VIRTIO_NET_F_STATUS, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_vq", VirtIONet, host_features,
> + VIRTIO_NET_F_CTRL_VQ, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_rx", VirtIONet, host_features,
> + VIRTIO_NET_F_CTRL_RX, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_vlan", VirtIONet, host_features,
> + VIRTIO_NET_F_CTRL_VLAN, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_rx_extra", VirtIONet, host_features,
> + VIRTIO_NET_F_CTRL_RX_EXTRA,
> ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_mac_addr", VirtIONet, host_features,
> + VIRTIO_NET_F_CTRL_MAC_ADDR,
> ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("ctrl_guest_offloads", VirtIONet,
> + host_features,
> + VIRTIO_NET_F_CTRL_GUEST_OFFLOADS,
> + ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("mq", VirtIONet, host_features,
> + VIRTIO_NET_F_MQ, ON_OFF_AUTO_OFF),
Probably for 'mq' there is no difference between 'auto' and 'on' ?
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("rss", VirtIONet, host_features,
> + VIRTIO_NET_F_RSS, ON_OFF_AUTO_OFF),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("hash", VirtIONet, host_features,
> + VIRTIO_NET_F_HASH_REPORT, ON_OFF_AUTO_OFF),
> DEFINE_PROP_ARRAY("ebpf-rss-fds", VirtIONet, nr_ebpf_rss_fds,
> ebpf_rss_fds, qdev_prop_string, char*),
> - DEFINE_PROP_BIT64("guest_rsc_ext", VirtIONet, host_features,
> + DEFINE_PROP_BIT64("guest_rsc_ext", VirtIONet, host_features.on_bits,
> VIRTIO_NET_F_RSC_EXT, false),
> DEFINE_PROP_UINT32("rsc_interval", VirtIONet, rsc_timeout,
> VIRTIO_NET_RSC_DEFAULT_INTERVAL),
> @@ -3979,12 +4034,12 @@ static Property virtio_net_properties[] = {
> DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN),
> DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
> DEFINE_PROP_BOOL("failover", VirtIONet, failover, false),
> - DEFINE_PROP_BIT64("guest_uso4", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_USO4, true),
> - DEFINE_PROP_BIT64("guest_uso6", VirtIONet, host_features,
> - VIRTIO_NET_F_GUEST_USO6, true),
> - DEFINE_PROP_BIT64("host_uso", VirtIONet, host_features,
> - VIRTIO_NET_F_HOST_USO, true),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_uso4", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_USO4, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("guest_uso6", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_USO6, ON_OFF_AUTO_AUTO),
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("host_uso", VirtIONet, host_features,
> + VIRTIO_NET_F_HOST_USO, ON_OFF_AUTO_AUTO),
> DEFINE_PROP_END_OF_LIST(),
> };
>
>
> --
> 2.44.0
>
