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)) {
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 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 3:17, 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
> >
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
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 3:00, 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
>
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