| Message ID | 2560bb4e8cabc550da07162c520aff3669a8f56f.1667136717.git.huangy81@chinatelecom.cn |
|---|---|
| State | New |
| Headers | show |
| Series | Fix the virtio features negotiation flaw | expand |
On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > Save the acked_features once it be configured by guest > virtio driver so it can't miss any features. > > Note that this patch also change the features saving logic > in chr_closed_bh, which originally backup features no matter > whether the features are 0 or not, but now do it only if > features aren't 0. I'm not sure how is this change even related to what we are trying to do (fix a bug). Explain here? > As to reset acked_features to 0 if needed, Qemu always > keeping the backup acked_features up-to-date, and save the > acked_features after virtio_net_set_features in advance, > including reset acked_features to 0, so the behavior is > also covered. > > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> > --- > hw/net/vhost_net.c | 9 +++++++++ > hw/net/virtio-net.c | 5 +++++ > include/net/vhost_net.h | 2 ++ > net/vhost-user.c | 6 +----- > 4 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > index d28f8b9..2bffc27 100644 > --- a/hw/net/vhost_net.c > +++ b/hw/net/vhost_net.c > @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) > return net->dev.acked_features; > } > > +void vhost_net_save_acked_features(NetClientState *nc) > +{ > + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { > + return; > + } > + > + vhost_user_save_acked_features(nc, false); > +} > + > static int vhost_net_get_fd(NetClientState *backend) > { > switch (backend->info->type) { > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index e9f696b..5f8f788 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > continue; > } > vhost_net_ack_features(get_vhost_net(nc->peer), features); > + /* > + * keep acked_features in NetVhostUserState up-to-date so it > + * can't miss any features configured by guest virtio driver. > + */ > + vhost_net_save_acked_features(nc->peer); > } > > if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h > index 387e913..3a5579b 100644 > --- a/include/net/vhost_net.h > +++ b/include/net/vhost_net.h > @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); > > uint64_t vhost_net_get_acked_features(VHostNetState *net); > > +void vhost_net_save_acked_features(NetClientState *nc); > + > int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); > > #endif > diff --git a/net/vhost-user.c b/net/vhost-user.c > index 74f349c..c512cc9 100644 > --- a/net/vhost-user.c > +++ b/net/vhost-user.c > @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) > s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); > > for (i = queues -1; i >= 0; i--) { > - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); > - > - if (s->vhost_net) { > - s->acked_features = vhost_net_get_acked_features(s->vhost_net); > - } > + vhost_user_save_acked_features(ncs[i], false); > } > > qmp_set_link(name, false, &err); Split this last chunk into a patch of its own? > -- > 1.8.3.1
On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > Save the acked_features once it be configured by guest > virtio driver so it can't miss any features. > > Note that this patch also change the features saving logic > in chr_closed_bh, which originally backup features no matter > whether the features are 0 or not, but now do it only if > features aren't 0. > > As to reset acked_features to 0 if needed, Qemu always > keeping the backup acked_features up-to-date, and save the > acked_features after virtio_net_set_features in advance, > including reset acked_features to 0, so the behavior is > also covered. > > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> > --- > hw/net/vhost_net.c | 9 +++++++++ > hw/net/virtio-net.c | 5 +++++ > include/net/vhost_net.h | 2 ++ > net/vhost-user.c | 6 +----- > 4 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > index d28f8b9..2bffc27 100644 > --- a/hw/net/vhost_net.c > +++ b/hw/net/vhost_net.c > @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) > return net->dev.acked_features; > } > > +void vhost_net_save_acked_features(NetClientState *nc) > +{ > + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { > + return; > + } > + > + vhost_user_save_acked_features(nc, false); > +} > + > static int vhost_net_get_fd(NetClientState *backend) > { > switch (backend->info->type) { > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index e9f696b..5f8f788 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > continue; > } > vhost_net_ack_features(get_vhost_net(nc->peer), features); > + /* > + * keep acked_features in NetVhostUserState up-to-date so it > + * can't miss any features configured by guest virtio driver. > + */ > + vhost_net_save_acked_features(nc->peer); > } > > if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { So when do you want to ack features but *not* save them? Is the effect of this patch, fundamentally, that guest features from virtio are always copied to vhost-user? Do we even need an extra copy in vhost user then? all this came in with: commit a463215b087c41d7ca94e51aa347cde523831873 Author: Marc-André Lureau <marcandre.lureau@redhat.com> Date: Mon Jun 6 18:45:05 2016 +0200 vhost-net: save & restore vhost-user acked features Marc-André do you remember why we have a copy of features in vhost-user and not just reuse the features from virtio? > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h > index 387e913..3a5579b 100644 > --- a/include/net/vhost_net.h > +++ b/include/net/vhost_net.h > @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); > > uint64_t vhost_net_get_acked_features(VHostNetState *net); > > +void vhost_net_save_acked_features(NetClientState *nc); > + > int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); > > #endif > diff --git a/net/vhost-user.c b/net/vhost-user.c > index 74f349c..c512cc9 100644 > --- a/net/vhost-user.c > +++ b/net/vhost-user.c > @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) > s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); > > for (i = queues -1; i >= 0; i--) { > - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); > - > - if (s->vhost_net) { > - s->acked_features = vhost_net_get_acked_features(s->vhost_net); > - } > + vhost_user_save_acked_features(ncs[i], false); > } > > qmp_set_link(name, false, &err); > -- > 1.8.3.1
在 2022/11/11 3:00, Michael S. Tsirkin 写道: > On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: >> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> >> Save the acked_features once it be configured by guest >> virtio driver so it can't miss any features. >> >> Note that this patch also change the features saving logic >> in chr_closed_bh, which originally backup features no matter >> whether the features are 0 or not, but now do it only if >> features aren't 0. > > I'm not sure how is this change even related to what we > are trying to do (fix a bug). Explain here? > For this series, all we want to do is to making sure acked_features in the NetVhostUserState is credible and uptodate in the scenario that virtio features negotiation and openvswitch service restart happens simultaneously. To make sure that happens, we save the acked_features to NetVhostUserState right after guest setting virtio-net features. Assume that we do not save acked_features to NetVhostUserState just as it is, the acked_features in NetVhostUserState has chance to be assigned only when chr_closed_bh/vhost_user_stop happen. Note that openvswitch service stop will cause chr_closed_bh happens and acked_features in vhost_dev will be stored into NetVhostUserState, if the acked_features in vhost_dev are out-of-date(may be updated in the next few seconds), so does the acked_features in NetVhostUserState after doing the assignment, this is the bug. Let's refine the scenario and derive the bug: qemu thread dpdk | | vhost_net_init() | | | assign acked_features in vhost_dev | with 0x40000000 | | openvswitch.service stop chr_closed_bh | | | assign acked_features in | NetVhostUserState with 0x40000000 | | | virtio_net_set_features() | | | assign acked_features in vhost_dev | with 0x7060a782 | | openvswitch.service start | | vhost_user_start | | | assign acked_features in vhost_dev | with 0x40000000 | | | As the step shows, if we do not keep the acked_features in NetVhostUserState up-to-date, the acked_features in vhost_dev may be reloaded with the wrong value(eg, 0x40000000) when vhost_user_start happens. > > >> As to reset acked_features to 0 if needed, Qemu always >> keeping the backup acked_features up-to-date, and save the >> acked_features after virtio_net_set_features in advance, >> including reset acked_features to 0, so the behavior is >> also covered. >> >> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> >> --- >> hw/net/vhost_net.c | 9 +++++++++ >> hw/net/virtio-net.c | 5 +++++ >> include/net/vhost_net.h | 2 ++ >> net/vhost-user.c | 6 +----- >> 4 files changed, 17 insertions(+), 5 deletions(-) >> >> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c >> index d28f8b9..2bffc27 100644 >> --- a/hw/net/vhost_net.c >> +++ b/hw/net/vhost_net.c >> @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) >> return net->dev.acked_features; >> } >> >> +void vhost_net_save_acked_features(NetClientState *nc) >> +{ >> + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { >> + return; >> + } >> + >> + vhost_user_save_acked_features(nc, false); >> +} >> + >> static int vhost_net_get_fd(NetClientState *backend) >> { >> switch (backend->info->type) { >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c >> index e9f696b..5f8f788 100644 >> --- a/hw/net/virtio-net.c >> +++ b/hw/net/virtio-net.c >> @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) >> continue; >> } >> vhost_net_ack_features(get_vhost_net(nc->peer), features); >> + /* >> + * keep acked_features in NetVhostUserState up-to-date so it >> + * can't miss any features configured by guest virtio driver. >> + */ >> + vhost_net_save_acked_features(nc->peer); >> } >> >> if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { >> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h >> index 387e913..3a5579b 100644 >> --- a/include/net/vhost_net.h >> +++ b/include/net/vhost_net.h >> @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); >> >> uint64_t vhost_net_get_acked_features(VHostNetState *net); >> >> +void vhost_net_save_acked_features(NetClientState *nc); >> + >> int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); >> >> #endif >> diff --git a/net/vhost-user.c b/net/vhost-user.c >> index 74f349c..c512cc9 100644 >> --- a/net/vhost-user.c >> +++ b/net/vhost-user.c >> @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) >> s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); >> >> for (i = queues -1; i >= 0; i--) { >> - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); >> - >> - if (s->vhost_net) { >> - s->acked_features = vhost_net_get_acked_features(s->vhost_net); >> - } >> + vhost_user_save_acked_features(ncs[i], false); >> } >> >> qmp_set_link(name, false, &err); > > > Split this last chunk into a patch of its own? > >> -- >> 1.8.3.1 >
The previous reply email has an text format error, please ignore and 在 2022/11/11 3:00, Michael S. Tsirkin 写道: > On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: >> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> >> Save the acked_features once it be configured by guest >> virtio driver so it can't miss any features. >> >> Note that this patch also change the features saving logic >> in chr_closed_bh, which originally backup features no matter >> whether the features are 0 or not, but now do it only if >> features aren't 0. > > I'm not sure how is this change even related to what we > are trying to do (fix a bug). Explain here? > For this series, all we want to do is to making sure acked_features in the NetVhostUserState is credible and uptodate in the scenario that virtio features negotiation and openvswitch service restart happens simultaneously. To make sure that happens, we save the acked_features to NetVhostUserState right after guest setting virtio-net features. Assume that we do not save acked_features to NetVhostUserState just as it is, the acked_features in NetVhostUserState has chance to be assigned only when chr_closed_bh/vhost_user_stop happen. Note that openvswitch service stop will cause chr_closed_bh happens and acked_features in vhost_dev will be stored into NetVhostUserState, if the acked_features in vhost_dev are out-of-date(may be updated in the next few seconds), so does the acked_features in NetVhostUserState after doing the assignment, this is the bug. Let's refine the scenario and derive the bug: qemu thread dpdk | | vhost_net_init() | | | assign acked_features in vhost_dev | with 0x40000000 | | openvswitch.service stop chr_closed_bh | | | assign acked_features in | NetVhostUserState with 0x40000000 | | | virtio_net_set_features() | | | assign acked_features in vhost_dev | with 0x7060a782 | | openvswitch.service start | | vhost_user_start | | | assign acked_features in vhost_dev | with 0x40000000 | | | As the step shows, if we do not keep the acked_features in NetVhostUserState up-to-date, the acked_features in vhost_dev may be reloaded with the wrong value(eg, 0x40000000) when vhost_user_start happens. > > >> As to reset acked_features to 0 if needed, Qemu always >> keeping the backup acked_features up-to-date, and save the >> acked_features after virtio_net_set_features in advance, >> including reset acked_features to 0, so the behavior is >> also covered. >> >> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> >> --- >> hw/net/vhost_net.c | 9 +++++++++ >> hw/net/virtio-net.c | 5 +++++ >> include/net/vhost_net.h | 2 ++ >> net/vhost-user.c | 6 +----- >> 4 files changed, 17 insertions(+), 5 deletions(-) >> >> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c >> index d28f8b9..2bffc27 100644 >> --- a/hw/net/vhost_net.c >> +++ b/hw/net/vhost_net.c >> @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) >> return net->dev.acked_features; >> } >> >> +void vhost_net_save_acked_features(NetClientState *nc) >> +{ >> + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { >> + return; >> + } >> + >> + vhost_user_save_acked_features(nc, false); >> +} >> + >> static int vhost_net_get_fd(NetClientState *backend) >> { >> switch (backend->info->type) { >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c >> index e9f696b..5f8f788 100644 >> --- a/hw/net/virtio-net.c >> +++ b/hw/net/virtio-net.c >> @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) >> continue; >> } >> vhost_net_ack_features(get_vhost_net(nc->peer), features); >> + /* >> + * keep acked_features in NetVhostUserState up-to-date so it >> + * can't miss any features configured by guest virtio driver. >> + */ >> + vhost_net_save_acked_features(nc->peer); >> } >> >> if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { >> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h >> index 387e913..3a5579b 100644 >> --- a/include/net/vhost_net.h >> +++ b/include/net/vhost_net.h >> @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); >> >> uint64_t vhost_net_get_acked_features(VHostNetState *net); >> >> +void vhost_net_save_acked_features(NetClientState *nc); >> + >> int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); >> >> #endif >> diff --git a/net/vhost-user.c b/net/vhost-user.c >> index 74f349c..c512cc9 100644 >> --- a/net/vhost-user.c >> +++ b/net/vhost-user.c >> @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) >> s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); >> >> for (i = queues -1; i >= 0; i--) { >> - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); >> - >> - if (s->vhost_net) { >> - s->acked_features = vhost_net_get_acked_features(s->vhost_net); >> - } >> + vhost_user_save_acked_features(ncs[i], false); >> } >> >> qmp_set_link(name, false, &err); > > > Split this last chunk into a patch of its own? > >> -- >> 1.8.3.1 >
在 2022/11/11 3:17, Michael S. Tsirkin 写道: > On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: >> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> >> Save the acked_features once it be configured by guest >> virtio driver so it can't miss any features. >> >> Note that this patch also change the features saving logic >> in chr_closed_bh, which originally backup features no matter >> whether the features are 0 or not, but now do it only if >> features aren't 0. >> >> As to reset acked_features to 0 if needed, Qemu always >> keeping the backup acked_features up-to-date, and save the >> acked_features after virtio_net_set_features in advance, >> including reset acked_features to 0, so the behavior is >> also covered. >> >> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> >> Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> >> --- >> hw/net/vhost_net.c | 9 +++++++++ >> hw/net/virtio-net.c | 5 +++++ >> include/net/vhost_net.h | 2 ++ >> net/vhost-user.c | 6 +----- >> 4 files changed, 17 insertions(+), 5 deletions(-) >> >> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c >> index d28f8b9..2bffc27 100644 >> --- a/hw/net/vhost_net.c >> +++ b/hw/net/vhost_net.c >> @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) >> return net->dev.acked_features; >> } >> >> +void vhost_net_save_acked_features(NetClientState *nc) >> +{ >> + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { >> + return; >> + } >> + >> + vhost_user_save_acked_features(nc, false); >> +} >> + >> static int vhost_net_get_fd(NetClientState *backend) >> { >> switch (backend->info->type) { >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c >> index e9f696b..5f8f788 100644 >> --- a/hw/net/virtio-net.c >> +++ b/hw/net/virtio-net.c >> @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) >> continue; >> } >> vhost_net_ack_features(get_vhost_net(nc->peer), features); >> + /* >> + * keep acked_features in NetVhostUserState up-to-date so it >> + * can't miss any features configured by guest virtio driver. >> + */ >> + vhost_net_save_acked_features(nc->peer); >> } >> >> if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { > > So when do you want to ack features but *not* save them? When openvswitch restart and reconnect and Qemu start the vhost_dev， acked_features in vhost_dev Qemu need to be initialized and the initialized value be fetched from acked_features int NetVhostUserState. At this time, acked_features may not be up-to-date but we want it. > > Is the effect of this patch, fundamentally, that guest features > from virtio are always copied to vhost-user? > Do we even need an extra copy in vhost user then? > I'm trying to explain this from my view, please point out the mistake if i failed. :) When socket used by vhost-user device disconnectted from openvswitch, Qemu will stop the vhost-user and clean up the whole struct of vhost_dev(include vm's memory region and acked_features), once socket is reconnected from openvswitch, Qemu will collect vm's memory region dynamically but as to acked_features, IMHO, Qemu can not fetch it from guest features of virtio-net, because acked_features are kind of different from guest features(bit 30 is different at least)，so Qemu need an extra copy. > > all this came in with: > > commit a463215b087c41d7ca94e51aa347cde523831873 > Author: Marc-André Lureau <marcandre.lureau@redhat.com> > Date: Mon Jun 6 18:45:05 2016 +0200 > > vhost-net: save & restore vhost-user acked features > > Marc-André do you remember why we have a copy of features in vhost-user > and not just reuse the features from virtio? > > >> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h >> index 387e913..3a5579b 100644 >> --- a/include/net/vhost_net.h >> +++ b/include/net/vhost_net.h >> @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); >> >> uint64_t vhost_net_get_acked_features(VHostNetState *net); >> >> +void vhost_net_save_acked_features(NetClientState *nc); >> + >> int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); >> >> #endif >> diff --git a/net/vhost-user.c b/net/vhost-user.c >> index 74f349c..c512cc9 100644 >> --- a/net/vhost-user.c >> +++ b/net/vhost-user.c >> @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) >> s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); >> >> for (i = queues -1; i >= 0; i--) { >> - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); >> - >> - if (s->vhost_net) { >> - s->acked_features = vhost_net_get_acked_features(s->vhost_net); >> - } >> + vhost_user_save_acked_features(ncs[i], false); >> } >> >> qmp_set_link(name, false, &err); >> -- >> 1.8.3.1 >
On Mon, Nov 14, 2022 at 11:35:30PM +0800, Hyman wrote: > > > 在 2022/11/11 3:17, Michael S. Tsirkin 写道: > > On Sun, Oct 30, 2022 at 09:52:39PM +0800, huangy81@chinatelecom.cn wrote: > > > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > > > > > Save the acked_features once it be configured by guest > > > virtio driver so it can't miss any features. > > > > > > Note that this patch also change the features saving logic > > > in chr_closed_bh, which originally backup features no matter > > > whether the features are 0 or not, but now do it only if > > > features aren't 0. > > > > > > As to reset acked_features to 0 if needed, Qemu always > > > keeping the backup acked_features up-to-date, and save the > > > acked_features after virtio_net_set_features in advance, > > > including reset acked_features to 0, so the behavior is > > > also covered. > > > > > > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn> > > > Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn> > > > --- > > > hw/net/vhost_net.c | 9 +++++++++ > > > hw/net/virtio-net.c | 5 +++++ > > > include/net/vhost_net.h | 2 ++ > > > net/vhost-user.c | 6 +----- > > > 4 files changed, 17 insertions(+), 5 deletions(-) > > > > > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > > > index d28f8b9..2bffc27 100644 > > > --- a/hw/net/vhost_net.c > > > +++ b/hw/net/vhost_net.c > > > @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) > > > return net->dev.acked_features; > > > } > > > +void vhost_net_save_acked_features(NetClientState *nc) > > > +{ > > > + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { > > > + return; > > > + } > > > + > > > + vhost_user_save_acked_features(nc, false); > > > +} > > > + > > > static int vhost_net_get_fd(NetClientState *backend) > > > { > > > switch (backend->info->type) { > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > index e9f696b..5f8f788 100644 > > > --- a/hw/net/virtio-net.c > > > +++ b/hw/net/virtio-net.c > > > @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) > > > continue; > > > } > > > vhost_net_ack_features(get_vhost_net(nc->peer), features); > > > + /* > > > + * keep acked_features in NetVhostUserState up-to-date so it > > > + * can't miss any features configured by guest virtio driver. > > > + */ > > > + vhost_net_save_acked_features(nc->peer); > > > } > > > if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { > > > > So when do you want to ack features but *not* save them? > When openvswitch restart and reconnect and Qemu start the vhost_dev， > acked_features in vhost_dev Qemu need to be initialized and the initialized > value be fetched from acked_features int NetVhostUserState. > At this time, acked_features may not be up-to-date but we want it. > > > > Is the effect of this patch, fundamentally, that guest features > > from virtio are always copied to vhost-user? > > Do we even need an extra copy in vhost user then? > > > I'm trying to explain this from my view, please point out the mistake if i > failed. :) > > When socket used by vhost-user device disconnectted from openvswitch, > Qemu will stop the vhost-user and clean up the whole struct of > vhost_dev(include vm's memory region and acked_features), once socket is > reconnected from openvswitch, Qemu will collect vm's memory region > dynamically but as to acked_features, IMHO, Qemu can not fetch it from guest > features of virtio-net, because acked_features are kind of different from > guest features(bit 30 is different at least)，so Qemu need an extra copy. Well we already have a list of valid frontend features in user_feature_bits. > > > > all this came in with: > > > > commit a463215b087c41d7ca94e51aa347cde523831873 > > Author: Marc-André Lureau <marcandre.lureau@redhat.com> > > Date: Mon Jun 6 18:45:05 2016 +0200 > > > > vhost-net: save & restore vhost-user acked features > > > > Marc-André do you remember why we have a copy of features in vhost-user > > and not just reuse the features from virtio? > > > > > > > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h > > > index 387e913..3a5579b 100644 > > > --- a/include/net/vhost_net.h > > > +++ b/include/net/vhost_net.h > > > @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); > > > uint64_t vhost_net_get_acked_features(VHostNetState *net); > > > +void vhost_net_save_acked_features(NetClientState *nc); > > > + > > > int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); > > > #endif > > > diff --git a/net/vhost-user.c b/net/vhost-user.c > > > index 74f349c..c512cc9 100644 > > > --- a/net/vhost-user.c > > > +++ b/net/vhost-user.c > > > @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) > > > s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); > > > for (i = queues -1; i >= 0; i--) { > > > - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); > > > - > > > - if (s->vhost_net) { > > > - s->acked_features = vhost_net_get_acked_features(s->vhost_net); > > > - } > > > + vhost_user_save_acked_features(ncs[i], false); > > > } > > > qmp_set_link(name, false, &err); > > > -- > > > 1.8.3.1 > >
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c index d28f8b9..2bffc27 100644 --- a/hw/net/vhost_net.c +++ b/hw/net/vhost_net.c @@ -141,6 +141,15 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net) return net->dev.acked_features; } +void vhost_net_save_acked_features(NetClientState *nc) +{ + if (nc->info->type != NET_CLIENT_DRIVER_VHOST_USER) { + return; + } + + vhost_user_save_acked_features(nc, false); +} + static int vhost_net_get_fd(NetClientState *backend) { switch (backend->info->type) { diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index e9f696b..5f8f788 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -924,6 +924,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) continue; } vhost_net_ack_features(get_vhost_net(nc->peer), features); + /* + * keep acked_features in NetVhostUserState up-to-date so it + * can't miss any features configured by guest virtio driver. + */ + vhost_net_save_acked_features(nc->peer); } if (virtio_has_feature(features, VIRTIO_NET_F_CTRL_VLAN)) { diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h index 387e913..3a5579b 100644 --- a/include/net/vhost_net.h +++ b/include/net/vhost_net.h @@ -46,6 +46,8 @@ int vhost_set_vring_enable(NetClientState * nc, int enable); uint64_t vhost_net_get_acked_features(VHostNetState *net); +void vhost_net_save_acked_features(NetClientState *nc); + int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu); #endif diff --git a/net/vhost-user.c b/net/vhost-user.c index 74f349c..c512cc9 100644 --- a/net/vhost-user.c +++ b/net/vhost-user.c @@ -258,11 +258,7 @@ static void chr_closed_bh(void *opaque) s = DO_UPCAST(NetVhostUserState, nc, ncs[0]); for (i = queues -1; i >= 0; i--) { - s = DO_UPCAST(NetVhostUserState, nc, ncs[i]); - - if (s->vhost_net) { - s->acked_features = vhost_net_get_acked_features(s->vhost_net); - } + vhost_user_save_acked_features(ncs[i], false); } qmp_set_link(name, false, &err);