| Message ID | 1479419887-10515-4-git-send-email-maxime.coquelin@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Nov 17, 2016 at 10:58:07PM +0100, Maxime Coquelin wrote: > If negotiated, virtio-net gets the advised MTU from vhost-net, > and provides it to the guest through a new virtio_net_config > entry. > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Aaron Conole <aconole@redhat.com > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> > --- > hw/net/virtio-net.c | 14 ++++++++++++++ > include/hw/virtio/virtio-net.h | 1 + > 2 files changed, 15 insertions(+) > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index 5009533..36843fe 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -55,6 +55,8 @@ static VirtIOFeature feature_sizes[] = { > .end = endof(struct virtio_net_config, status)}, > {.flags = 1 << VIRTIO_NET_F_MQ, > .end = endof(struct virtio_net_config, max_virtqueue_pairs)}, > + {.flags = 1 << VIRTIO_NET_F_MTU, > + .end = endof(struct virtio_net_config, mtu)}, > {} > }; > > @@ -81,6 +83,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config) > > virtio_stw_p(vdev, &netcfg.status, n->status); > virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues); > + virtio_stw_p(vdev, &netcfg.mtu, n->mtu); > memcpy(netcfg.mac, n->mac, ETH_ALEN); > memcpy(config, &netcfg, n->config_size); > } > @@ -636,6 +639,14 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > } else { > memset(n->vlans, 0xff, MAX_VLAN >> 3); > } > + > + if (virtio_has_feature(features, VIRTIO_NET_F_MTU)) { > + NetClientState *nc = qemu_get_queue(n->nic); > + > + if (get_vhost_net(nc->peer)) { > + n->mtu = vhost_net_get_mtu(get_vhost_net(nc->peer)); This means migration breaks silently if you move from a bigger to smaller mtu. We don't necessarily have to make it work, but it should be detected and reported. > + } > + } > } > > static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd, What about non-vhost traffic? You need to ensure guest does not get bigger packets. > @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) > { > int i, config_size = 0; > virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); > + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); > for (i = 0; feature_sizes[i].flags != 0; i++) { > if (host_features & feature_sizes[i].flags) { > config_size = MAX(feature_sizes[i].end, config_size); > @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { > DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), > DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, > VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), > + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, > + VIRTIO_NET_F_MTU, true), > DEFINE_PROP_END_OF_LIST(), > }; > Cross version migration support is missing here. > diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h > index 0ced975..b6394c8 100644 > --- a/include/hw/virtio/virtio-net.h > +++ b/include/hw/virtio/virtio-net.h > @@ -96,6 +96,7 @@ typedef struct VirtIONet { > QEMUTimer *announce_timer; > int announce_counter; > bool needs_vnet_hdr_swap; > + uint16_t mtu; > } VirtIONet; > > void virtio_net_set_netclient_name(VirtIONet *n, const char *name, > -- > 2.7.4
On 11/17/2016 11:38 PM, Michael S. Tsirkin wrote: > On Thu, Nov 17, 2016 at 10:58:07PM +0100, Maxime Coquelin wrote: >> If negotiated, virtio-net gets the advised MTU from vhost-net, >> and provides it to the guest through a new virtio_net_config >> entry. >> >> Cc: Michael S. Tsirkin <mst@redhat.com> >> Cc: Aaron Conole <aconole@redhat.com >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> >> --- >> hw/net/virtio-net.c | 14 ++++++++++++++ >> include/hw/virtio/virtio-net.h | 1 + >> 2 files changed, 15 insertions(+) >> >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c >> index 5009533..36843fe 100644 >> --- a/hw/net/virtio-net.c >> +++ b/hw/net/virtio-net.c >> @@ -55,6 +55,8 @@ static VirtIOFeature feature_sizes[] = { >> .end = endof(struct virtio_net_config, status)}, >> {.flags = 1 << VIRTIO_NET_F_MQ, >> .end = endof(struct virtio_net_config, max_virtqueue_pairs)}, >> + {.flags = 1 << VIRTIO_NET_F_MTU, >> + .end = endof(struct virtio_net_config, mtu)}, >> {} >> }; >> >> @@ -81,6 +83,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config) >> >> virtio_stw_p(vdev, &netcfg.status, n->status); >> virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues); >> + virtio_stw_p(vdev, &netcfg.mtu, n->mtu); >> memcpy(netcfg.mac, n->mac, ETH_ALEN); >> memcpy(config, &netcfg, n->config_size); >> } >> @@ -636,6 +639,14 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) >> } else { >> memset(n->vlans, 0xff, MAX_VLAN >> 3); >> } >> + >> + if (virtio_has_feature(features, VIRTIO_NET_F_MTU)) { >> + NetClientState *nc = qemu_get_queue(n->nic); >> + >> + if (get_vhost_net(nc->peer)) { >> + n->mtu = vhost_net_get_mtu(get_vhost_net(nc->peer)); > > > This means migration breaks silently if you move from a bigger to > smaller mtu. We don't necessarily have to make it work, > but it should be detected and reported. Good point. I planned to investigate migration case while looking deeper at vhost-user versionning topic. Moving from bigger to smaller MTU is indeed a problem, because the backend may not support received buffer size. Isn't also a problem when moving from smaller to bigger MTU, as it no more respect the contract old host negotiated with the guest? > >> + } >> + } >> } >> >> static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd, > > What about non-vhost traffic? You need to ensure guest does > not get bigger packets. Ok, do you confirm checking in virtio_net_receive() that buffer size is smaller or equal than MTU is enough? > > >> @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) >> { >> int i, config_size = 0; >> virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); >> + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); >> for (i = 0; feature_sizes[i].flags != 0; i++) { >> if (host_features & feature_sizes[i].flags) { >> config_size = MAX(feature_sizes[i].end, config_size); >> @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { >> DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), >> DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, >> VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), >> + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, >> + VIRTIO_NET_F_MTU, true), >> DEFINE_PROP_END_OF_LIST(), >> }; >> > > Cross version migration support is missing here. Sorry, I'm not sure to understand what you expect here. Could you please provide more details? > >> diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h >> index 0ced975..b6394c8 100644 >> --- a/include/hw/virtio/virtio-net.h >> +++ b/include/hw/virtio/virtio-net.h >> @@ -96,6 +96,7 @@ typedef struct VirtIONet { >> QEMUTimer *announce_timer; >> int announce_counter; >> bool needs_vnet_hdr_swap; >> + uint16_t mtu; >> } VirtIONet; >> >> void virtio_net_set_netclient_name(VirtIONet *n, const char *name, >> -- >> 2.7.4 Thanks, Maxime
On Mon, Nov 21, 2016 at 01:34:32PM +0100, Maxime Coquelin wrote: > > > On 11/17/2016 11:38 PM, Michael S. Tsirkin wrote: > > On Thu, Nov 17, 2016 at 10:58:07PM +0100, Maxime Coquelin wrote: > > > If negotiated, virtio-net gets the advised MTU from vhost-net, > > > and provides it to the guest through a new virtio_net_config > > > entry. > > > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > > Cc: Aaron Conole <aconole@redhat.com > > > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> > > > --- > > > hw/net/virtio-net.c | 14 ++++++++++++++ > > > include/hw/virtio/virtio-net.h | 1 + > > > 2 files changed, 15 insertions(+) > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > index 5009533..36843fe 100644 > > > --- a/hw/net/virtio-net.c > > > +++ b/hw/net/virtio-net.c > > > @@ -55,6 +55,8 @@ static VirtIOFeature feature_sizes[] = { > > > .end = endof(struct virtio_net_config, status)}, > > > {.flags = 1 << VIRTIO_NET_F_MQ, > > > .end = endof(struct virtio_net_config, max_virtqueue_pairs)}, > > > + {.flags = 1 << VIRTIO_NET_F_MTU, > > > + .end = endof(struct virtio_net_config, mtu)}, > > > {} > > > }; > > > > > > @@ -81,6 +83,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config) > > > > > > virtio_stw_p(vdev, &netcfg.status, n->status); > > > virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues); > > > + virtio_stw_p(vdev, &netcfg.mtu, n->mtu); > > > memcpy(netcfg.mac, n->mac, ETH_ALEN); > > > memcpy(config, &netcfg, n->config_size); > > > } > > > @@ -636,6 +639,14 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > > > } else { > > > memset(n->vlans, 0xff, MAX_VLAN >> 3); > > > } > > > + > > > + if (virtio_has_feature(features, VIRTIO_NET_F_MTU)) { > > > + NetClientState *nc = qemu_get_queue(n->nic); > > > + > > > + if (get_vhost_net(nc->peer)) { > > > + n->mtu = vhost_net_get_mtu(get_vhost_net(nc->peer)); > > > > > > This means migration breaks silently if you move from a bigger to > > smaller mtu. We don't necessarily have to make it work, > > but it should be detected and reported. > > Good point. > I planned to investigate migration case while looking deeper at > vhost-user versionning topic. > > Moving from bigger to smaller MTU is indeed a problem, because the > backend may not support received buffer size. > > Isn't also a problem when moving from smaller to bigger MTU, as it no > more respect the contract old host negotiated with the guest? Depends on what assumptions backends makes, but generally yes. > > > > > + } > > > + } > > > } > > > > > > static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd, > > > > What about non-vhost traffic? You need to ensure guest does > > not get bigger packets. > Ok, do you confirm checking in virtio_net_receive() that buffer size is > smaller or equal than MTU is enough? > > > > > > > > @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) > > > { > > > int i, config_size = 0; > > > virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); > > > + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); > > > for (i = 0; feature_sizes[i].flags != 0; i++) { > > > if (host_features & feature_sizes[i].flags) { > > > config_size = MAX(feature_sizes[i].end, config_size); > > > @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { > > > DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), > > > DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, > > > VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), > > > + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, > > > + VIRTIO_NET_F_MTU, true), > > > DEFINE_PROP_END_OF_LIST(), > > > }; > > > > > > > Cross version migration support is missing here. > Sorry, I'm not sure to understand what you expect here. > Could you please provide more details? feature bits must be consistent for a given machine type. So you can't add them unconditionally for old machine types, they must look the same as they looked when we put that machine type out. > > > > > diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h > > > index 0ced975..b6394c8 100644 > > > --- a/include/hw/virtio/virtio-net.h > > > +++ b/include/hw/virtio/virtio-net.h > > > @@ -96,6 +96,7 @@ typedef struct VirtIONet { > > > QEMUTimer *announce_timer; > > > int announce_counter; > > > bool needs_vnet_hdr_swap; > > > + uint16_t mtu; > > > } VirtIONet; > > > > > > void virtio_net_set_netclient_name(VirtIONet *n, const char *name, > > > -- > > > 2.7.4 > > Thanks, > Maxime
On 11/21/2016 05:48 PM, Michael S. Tsirkin wrote: >>>> > > > @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) >>>> > > > { >>>> > > > int i, config_size = 0; >>>> > > > virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); >>>> > > > + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); >>>> > > > for (i = 0; feature_sizes[i].flags != 0; i++) { >>>> > > > if (host_features & feature_sizes[i].flags) { >>>> > > > config_size = MAX(feature_sizes[i].end, config_size); >>>> > > > @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { >>>> > > > DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), >>>> > > > DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, >>>> > > > VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), >>>> > > > + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, >>>> > > > + VIRTIO_NET_F_MTU, true), >>>> > > > DEFINE_PROP_END_OF_LIST(), >>>> > > > }; >>>> > > > >>> > > >>> > > Cross version migration support is missing here. >> > Sorry, I'm not sure to understand what you expect here. >> > Could you please provide more details? > feature bits must be consistent for a given machine type. > So you can't add them unconditionally for old machine > types, they must look the same as they looked when > we put that machine type out. Ok, thanks for clarifying. IIUC, idea is to let it enabled by default, and add entries in HW_COMPAT_2_x macros to disable it in all previous versions? Thanks, Maxime
On Tue, Nov 22, 2016 at 01:11:50PM +0100, Maxime Coquelin wrote: > > > On 11/21/2016 05:48 PM, Michael S. Tsirkin wrote: > > > > > > > > @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) > > > > > > > > { > > > > > > > > int i, config_size = 0; > > > > > > > > virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); > > > > > > > > + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); > > > > > > > > for (i = 0; feature_sizes[i].flags != 0; i++) { > > > > > > > > if (host_features & feature_sizes[i].flags) { > > > > > > > > config_size = MAX(feature_sizes[i].end, config_size); > > > > > > > > @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { > > > > > > > > DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), > > > > > > > > DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, > > > > > > > > VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), > > > > > > > > + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, > > > > > > > > + VIRTIO_NET_F_MTU, true), > > > > > > > > DEFINE_PROP_END_OF_LIST(), > > > > > > > > }; > > > > > > > > > > > > > > > > > > > > Cross version migration support is missing here. > > > > Sorry, I'm not sure to understand what you expect here. > > > > Could you please provide more details? > > feature bits must be consistent for a given machine type. > > So you can't add them unconditionally for old machine > > types, they must look the same as they looked when > > we put that machine type out. > > Ok, thanks for clarifying. > IIUC, idea is to let it enabled by default, and add entries in > HW_COMPAT_2_x macros to disable it in all previous versions? > > Thanks, > Maxime I suspect you should keep it disabled by default, set it when user specifies the mtu.
On 11/22/2016 03:18 PM, Michael S. Tsirkin wrote: > On Tue, Nov 22, 2016 at 01:11:50PM +0100, Maxime Coquelin wrote: >> >> >> On 11/21/2016 05:48 PM, Michael S. Tsirkin wrote: >>>>>>>>> @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) >>>>>>>>> { >>>>>>>>> int i, config_size = 0; >>>>>>>>> virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); >>>>>>>>> + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); >>>>>>>>> for (i = 0; feature_sizes[i].flags != 0; i++) { >>>>>>>>> if (host_features & feature_sizes[i].flags) { >>>>>>>>> config_size = MAX(feature_sizes[i].end, config_size); >>>>>>>>> @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { >>>>>>>>> DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), >>>>>>>>> DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, >>>>>>>>> VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), >>>>>>>>> + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, >>>>>>>>> + VIRTIO_NET_F_MTU, true), >>>>>>>>> DEFINE_PROP_END_OF_LIST(), >>>>>>>>> }; >>>>>>>>> >>>>>>> >>>>>>> Cross version migration support is missing here. >>>>> Sorry, I'm not sure to understand what you expect here. >>>>> Could you please provide more details? >>> feature bits must be consistent for a given machine type. >>> So you can't add them unconditionally for old machine >>> types, they must look the same as they looked when >>> we put that machine type out. >> >> Ok, thanks for clarifying. >> IIUC, idea is to let it enabled by default, and add entries in >> HW_COMPAT_2_x macros to disable it in all previous versions? >> >> Thanks, >> Maxime > > I suspect you should keep it disabled by default, > set it when user specifies the mtu. Yes, that make sense. Thanks, Maxime
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 5009533..36843fe 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -55,6 +55,8 @@ static VirtIOFeature feature_sizes[] = { .end = endof(struct virtio_net_config, status)}, {.flags = 1 << VIRTIO_NET_F_MQ, .end = endof(struct virtio_net_config, max_virtqueue_pairs)}, + {.flags = 1 << VIRTIO_NET_F_MTU, + .end = endof(struct virtio_net_config, mtu)}, {} }; @@ -81,6 +83,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config) virtio_stw_p(vdev, &netcfg.status, n->status); virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues); + virtio_stw_p(vdev, &netcfg.mtu, n->mtu); memcpy(netcfg.mac, n->mac, ETH_ALEN); memcpy(config, &netcfg, n->config_size); } @@ -636,6 +639,14 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) } else { memset(n->vlans, 0xff, MAX_VLAN >> 3); } + + if (virtio_has_feature(features, VIRTIO_NET_F_MTU)) { + NetClientState *nc = qemu_get_queue(n->nic); + + if (get_vhost_net(nc->peer)) { + n->mtu = vhost_net_get_mtu(get_vhost_net(nc->peer)); + } + } } static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd, @@ -1695,6 +1706,7 @@ static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features) { int i, config_size = 0; virtio_add_feature(&host_features, VIRTIO_NET_F_MAC); + virtio_add_feature(&host_features, VIRTIO_NET_F_MTU); for (i = 0; feature_sizes[i].flags != 0; i++) { if (host_features & feature_sizes[i].flags) { config_size = MAX(feature_sizes[i].end, config_size); @@ -1922,6 +1934,8 @@ static Property virtio_net_properties[] = { DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), + DEFINE_PROP_BIT("host_mtu", VirtIONet, host_features, + VIRTIO_NET_F_MTU, true), DEFINE_PROP_END_OF_LIST(), }; diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h index 0ced975..b6394c8 100644 --- a/include/hw/virtio/virtio-net.h +++ b/include/hw/virtio/virtio-net.h @@ -96,6 +96,7 @@ typedef struct VirtIONet { QEMUTimer *announce_timer; int announce_counter; bool needs_vnet_hdr_swap; + uint16_t mtu; } VirtIONet; void virtio_net_set_netclient_name(VirtIONet *n, const char *name,
If negotiated, virtio-net gets the advised MTU from vhost-net, and provides it to the guest through a new virtio_net_config entry. Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Aaron Conole <aconole@redhat.com Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> --- hw/net/virtio-net.c | 14 ++++++++++++++ include/hw/virtio/virtio-net.h | 1 + 2 files changed, 15 insertions(+)