| Message ID | 1438593754-30005-2-git-send-email-thibaut.collet@6wind.com |
|---|---|
| State | New |
| Headers | show |
Hi Thibaut On Mon, Aug 3, 2015 at 11:22 AM, Thibaut Collet <thibaut.collet@6wind.com> wrote: > Some vhost user backends are able to support live migration. > To provide this service the following features must be added: > 1. Add the VIRTIO_NET_F_GUEST_ANNOUNCE capability to vhost-net when netdev > backend is vhost-user. > 2. Provide a nop receive callback to vhost-user. > This callback is used only by qemu_announce_self after a migration to send > fake RARP to avoid network outage for peers talking to the migrated guest. > - For guest with GUEST_ANNOUNCE capabilities these packets must be discarded, > GARP are sent by the guest thanks the GUEST_ANNOUNCE. > - For guest without GUEST_ANNOUNCE capabilities these packets are discarded > too, migration termination is notified when the guest sends packets. > > Signed-off-by: Thibaut Collet <thibaut.collet@6wind.com> > --- > hw/net/vhost_net.c | 2 ++ > net/vhost-user.c | 25 +++++++++++++++++++++++-- > 2 files changed, 25 insertions(+), 2 deletions(-) > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > index c864237..9850520 100644 > --- a/hw/net/vhost_net.c > +++ b/hw/net/vhost_net.c > @@ -85,6 +85,8 @@ static const int user_feature_bits[] = { > VIRTIO_NET_F_CTRL_MAC_ADDR, > VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, > > + VIRTIO_NET_F_GUEST_ANNOUNCE, > + > VIRTIO_NET_F_MQ, > > VHOST_INVALID_FEATURE_BIT > diff --git a/net/vhost-user.c b/net/vhost-user.c > index 93dcecd..2290271 100644 > --- a/net/vhost-user.c > +++ b/net/vhost-user.c > @@ -65,6 +65,28 @@ static void vhost_user_stop(VhostUserState *s) > s->vhost_net = 0; > } > > +static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf, > + size_t size) > +{ > + /* A live migration is done. Display an error if the packet is not a RARP. > + * RARP are just discarded: guest is already notified about live migration > + * by the virtio-net NIC or by the vhost-user backend. > + */ > + if (size != 60) { > + static int display_trace = 1; > + > + if (display_trace) { > + fprintf(stderr, > + "Vhost user expects only RARP (size 60)." > + "Receives unexpected packets with size %lu\n", > + size); > + fflush(stderr); > + display_trace = 0; > + } > + } > + return size; > +} This warning appears during a dummy boot with vapp: qemu-system-x86_64 -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs/,share=on -numa node,memdev=mem -netdev vhost-user,id=net0,chardev=chr0,vhostforce -device virtio-net-pci,netdev=net0 -chardev socket,id=chr0,path=/tmp/vapp.sock. I think silentely returning 0 (without warning) is the right way to keep the packets queued in the ring instead. But I must say I am quite confused as this is triggered by a VIRTIO_PCI_QUEUE_NOTIFY ioport write, and I fail to see how vhost-user handles it then without eventfd kick... > static void vhost_user_cleanup(NetClientState *nc) > { > VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc); > @@ -90,6 +112,7 @@ static bool vhost_user_has_ufo(NetClientState *nc) > static NetClientInfo net_vhost_user_info = { > .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER, > .size = sizeof(VhostUserState), > + .receive = vhost_user_receive, > .cleanup = vhost_user_cleanup, > .has_vnet_hdr = vhost_user_has_vnet_hdr, > .has_ufo = vhost_user_has_ufo, > @@ -143,8 +166,6 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, > > s = DO_UPCAST(VhostUserState, nc, nc); > > - /* We don't provide a receive callback */ > - s->nc.receive_disabled = 1; > s->chr = chr; > > qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s); > -- > 1.7.10.4 >
On Tue, Aug 4, 2015 at 7:50 PM, Marc-André Lureau <marcandre.lureau@gmail.com> wrote: > Hi Thibaut > > On Mon, Aug 3, 2015 at 11:22 AM, Thibaut Collet > <thibaut.collet@6wind.com> wrote: >> Some vhost user backends are able to support live migration. >> To provide this service the following features must be added: >> 1. Add the VIRTIO_NET_F_GUEST_ANNOUNCE capability to vhost-net when netdev >> backend is vhost-user. >> 2. Provide a nop receive callback to vhost-user. >> This callback is used only by qemu_announce_self after a migration to send >> fake RARP to avoid network outage for peers talking to the migrated guest. >> - For guest with GUEST_ANNOUNCE capabilities these packets must be discarded, >> GARP are sent by the guest thanks the GUEST_ANNOUNCE. >> - For guest without GUEST_ANNOUNCE capabilities these packets are discarded >> too, migration termination is notified when the guest sends packets. >> >> Signed-off-by: Thibaut Collet <thibaut.collet@6wind.com> >> --- >> hw/net/vhost_net.c | 2 ++ >> net/vhost-user.c | 25 +++++++++++++++++++++++-- >> 2 files changed, 25 insertions(+), 2 deletions(-) >> >> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c >> index c864237..9850520 100644 >> --- a/hw/net/vhost_net.c >> +++ b/hw/net/vhost_net.c >> @@ -85,6 +85,8 @@ static const int user_feature_bits[] = { >> VIRTIO_NET_F_CTRL_MAC_ADDR, >> VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, >> >> + VIRTIO_NET_F_GUEST_ANNOUNCE, >> + >> VIRTIO_NET_F_MQ, >> >> VHOST_INVALID_FEATURE_BIT >> diff --git a/net/vhost-user.c b/net/vhost-user.c >> index 93dcecd..2290271 100644 >> --- a/net/vhost-user.c >> +++ b/net/vhost-user.c >> @@ -65,6 +65,28 @@ static void vhost_user_stop(VhostUserState *s) >> s->vhost_net = 0; >> } >> >> +static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf, >> + size_t size) >> +{ >> + /* A live migration is done. Display an error if the packet is not a RARP. >> + * RARP are just discarded: guest is already notified about live migration >> + * by the virtio-net NIC or by the vhost-user backend. >> + */ >> + if (size != 60) { >> + static int display_trace = 1; >> + >> + if (display_trace) { >> + fprintf(stderr, >> + "Vhost user expects only RARP (size 60)." >> + "Receives unexpected packets with size %lu\n", >> + size); >> + fflush(stderr); >> + display_trace = 0; >> + } >> + } >> + return size; >> +} > > This warning appears during a dummy boot with vapp: qemu-system-x86_64 > -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs/,share=on > -numa node,memdev=mem -netdev > vhost-user,id=net0,chardev=chr0,vhostforce -device > virtio-net-pci,netdev=net0 -chardev > socket,id=chr0,path=/tmp/vapp.sock. > > I think silentely returning 0 (without warning) is the right way to > keep the packets queued in the ring instead. But I must say I am quite > confused as this is triggered by a VIRTIO_PCI_QUEUE_NOTIFY ioport > write, and I fail to see how vhost-user handles it then without > eventfd kick... > >> static void vhost_user_cleanup(NetClientState *nc) >> { >> VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc); >> @@ -90,6 +112,7 @@ static bool vhost_user_has_ufo(NetClientState *nc) >> static NetClientInfo net_vhost_user_info = { >> .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER, >> .size = sizeof(VhostUserState), >> + .receive = vhost_user_receive, >> .cleanup = vhost_user_cleanup, >> .has_vnet_hdr = vhost_user_has_vnet_hdr, >> .has_ufo = vhost_user_has_ufo, >> @@ -143,8 +166,6 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, >> >> s = DO_UPCAST(VhostUserState, nc, nc); >> >> - /* We don't provide a receive callback */ >> - s->nc.receive_disabled = 1; >> s->chr = chr; >> >> qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s); >> -- >> 1.7.10.4 >> > > > > -- > Marc-André Lureau Hi, I have reproduced the issue and the message receive by vhost-user is quite strange: this message is a virtio header plus a bootp/dhcp request (I do not understand why there are the virtio header) With a dummy boot, vhost user backend already receives 4 bootp/dhcp requests form the bios guest so I do not see any interest to transmit this request to vhostuser backend. I suggest to remove the warning and discard the dhcp/bootp request (it is useless to duplicate bootp/dhcp request) Thibaut.
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c index c864237..9850520 100644 --- a/hw/net/vhost_net.c +++ b/hw/net/vhost_net.c @@ -85,6 +85,8 @@ static const int user_feature_bits[] = { VIRTIO_NET_F_CTRL_MAC_ADDR, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, + VIRTIO_NET_F_GUEST_ANNOUNCE, + VIRTIO_NET_F_MQ, VHOST_INVALID_FEATURE_BIT diff --git a/net/vhost-user.c b/net/vhost-user.c index 93dcecd..2290271 100644 --- a/net/vhost-user.c +++ b/net/vhost-user.c @@ -65,6 +65,28 @@ static void vhost_user_stop(VhostUserState *s) s->vhost_net = 0; } +static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf, + size_t size) +{ + /* A live migration is done. Display an error if the packet is not a RARP. + * RARP are just discarded: guest is already notified about live migration + * by the virtio-net NIC or by the vhost-user backend. + */ + if (size != 60) { + static int display_trace = 1; + + if (display_trace) { + fprintf(stderr, + "Vhost user expects only RARP (size 60)." + "Receives unexpected packets with size %lu\n", + size); + fflush(stderr); + display_trace = 0; + } + } + return size; +} + static void vhost_user_cleanup(NetClientState *nc) { VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc); @@ -90,6 +112,7 @@ static bool vhost_user_has_ufo(NetClientState *nc) static NetClientInfo net_vhost_user_info = { .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER, .size = sizeof(VhostUserState), + .receive = vhost_user_receive, .cleanup = vhost_user_cleanup, .has_vnet_hdr = vhost_user_has_vnet_hdr, .has_ufo = vhost_user_has_ufo, @@ -143,8 +166,6 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, s = DO_UPCAST(VhostUserState, nc, nc); - /* We don't provide a receive callback */ - s->nc.receive_disabled = 1; s->chr = chr; qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
Some vhost user backends are able to support live migration. To provide this service the following features must be added: 1. Add the VIRTIO_NET_F_GUEST_ANNOUNCE capability to vhost-net when netdev backend is vhost-user. 2. Provide a nop receive callback to vhost-user. This callback is used only by qemu_announce_self after a migration to send fake RARP to avoid network outage for peers talking to the migrated guest. - For guest with GUEST_ANNOUNCE capabilities these packets must be discarded, GARP are sent by the guest thanks the GUEST_ANNOUNCE. - For guest without GUEST_ANNOUNCE capabilities these packets are discarded too, migration termination is notified when the guest sends packets. Signed-off-by: Thibaut Collet <thibaut.collet@6wind.com> --- hw/net/vhost_net.c | 2 ++ net/vhost-user.c | 25 +++++++++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-)