Re: [PATCH net] vsock/virtio: enable VQs early on probe

2022-03-22 Thread Stefano Garzarella

On Tue, Mar 22, 2022 at 10:09:06AM -0400, Michael S. Tsirkin wrote:

On Tue, Mar 22, 2022 at 03:05:00PM +0100, Stefano Garzarella wrote:

On Tue, Mar 22, 2022 at 09:36:14AM -0400, Michael S. Tsirkin wrote:
> On Tue, Mar 22, 2022 at 11:38:23AM +0100, Stefano Garzarella wrote:
> > virtio spec requires drivers to set DRIVER_OK before using VQs.
> > This is set automatically after probe returns, but virtio-vsock
> > driver uses VQs in the probe function to fill rx and event VQs
> > with new buffers.
>
>
> So this is a spec violation. absolutely.
>
> > Let's fix this, calling virtio_device_ready() before using VQs
> > in the probe function.
> >
> > Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
> > Signed-off-by: Stefano Garzarella 
> > ---
> >  net/vmw_vsock/virtio_transport.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/net/vmw_vsock/virtio_transport.c 
b/net/vmw_vsock/virtio_transport.c
> > index 5afc194a58bb..b1962f8cd502 100644
> > --- a/net/vmw_vsock/virtio_transport.c
> > +++ b/net/vmw_vsock/virtio_transport.c
> > @@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device 
*vdev)
> >   INIT_WORK(>event_work, virtio_transport_event_work);
> >   INIT_WORK(>send_pkt_work, virtio_transport_send_pkt_work);
> >
> > + virtio_device_ready(vdev);
> > +
> >   mutex_lock(>tx_lock);
> >   vsock->tx_run = true;
> >   mutex_unlock(>tx_lock);
>
> Here's the whole code snippet:
>
>
>mutex_lock(>tx_lock);
>vsock->tx_run = true;
>mutex_unlock(>tx_lock);
>
>mutex_lock(>rx_lock);
>virtio_vsock_rx_fill(vsock);
>vsock->rx_run = true;
>mutex_unlock(>rx_lock);
>
>mutex_lock(>event_lock);
>virtio_vsock_event_fill(vsock);
>vsock->event_run = true;
>mutex_unlock(>event_lock);
>
>if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
>vsock->seqpacket_allow = true;
>
>vdev->priv = vsock;
>rcu_assign_pointer(the_virtio_vsock, vsock);
>
>mutex_unlock(_virtio_vsock_mutex);
>
>
> I worry that this is not the only problem here:
> seqpacket_allow and setting of vdev->priv at least after
> device is active look suspicious.

Right, so if you agree I'll move these before virtio_device_ready().

> E.g.:
>
> static void virtio_vsock_event_done(struct virtqueue *vq)
> {
>struct virtio_vsock *vsock = vq->vdev->priv;
>
>if (!vsock)
>return;
>queue_work(virtio_vsock_workqueue, >event_work);
> }
>
> looks like it will miss events now they will be reported earlier.
> One might say that since vq has been kicked it might send
> interrupts earlier too so not a new problem, but
> there's a chance device actually waits until DRIVER_OK
> to start operating.

Yes I see, should I break into 2 patches (one where I move the code already
present and this one)?

Maybe a single patch is fine since it's the complete solution.

Thank you for the detailed explanation,
Stefano


Two I think since movement can be backported to before the hardening
effort.


Yep, maybe 3 since seqpacket was added later.

Thanks,
Stefano

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization


Re: [PATCH net] vsock/virtio: enable VQs early on probe

2022-03-22 Thread Michael S. Tsirkin
On Tue, Mar 22, 2022 at 03:05:00PM +0100, Stefano Garzarella wrote:
> On Tue, Mar 22, 2022 at 09:36:14AM -0400, Michael S. Tsirkin wrote:
> > On Tue, Mar 22, 2022 at 11:38:23AM +0100, Stefano Garzarella wrote:
> > > virtio spec requires drivers to set DRIVER_OK before using VQs.
> > > This is set automatically after probe returns, but virtio-vsock
> > > driver uses VQs in the probe function to fill rx and event VQs
> > > with new buffers.
> > 
> > 
> > So this is a spec violation. absolutely.
> > 
> > > Let's fix this, calling virtio_device_ready() before using VQs
> > > in the probe function.
> > > 
> > > Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
> > > Signed-off-by: Stefano Garzarella 
> > > ---
> > >  net/vmw_vsock/virtio_transport.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/net/vmw_vsock/virtio_transport.c 
> > > b/net/vmw_vsock/virtio_transport.c
> > > index 5afc194a58bb..b1962f8cd502 100644
> > > --- a/net/vmw_vsock/virtio_transport.c
> > > +++ b/net/vmw_vsock/virtio_transport.c
> > > @@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device 
> > > *vdev)
> > >   INIT_WORK(>event_work, virtio_transport_event_work);
> > >   INIT_WORK(>send_pkt_work, virtio_transport_send_pkt_work);
> > > 
> > > + virtio_device_ready(vdev);
> > > +
> > >   mutex_lock(>tx_lock);
> > >   vsock->tx_run = true;
> > >   mutex_unlock(>tx_lock);
> > 
> > Here's the whole code snippet:
> > 
> > 
> >mutex_lock(>tx_lock);
> >vsock->tx_run = true;
> >mutex_unlock(>tx_lock);
> > 
> >mutex_lock(>rx_lock);
> >virtio_vsock_rx_fill(vsock);
> >vsock->rx_run = true;
> >mutex_unlock(>rx_lock);
> > 
> >mutex_lock(>event_lock);
> >virtio_vsock_event_fill(vsock);
> >vsock->event_run = true;
> >mutex_unlock(>event_lock);
> > 
> >if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
> >vsock->seqpacket_allow = true;
> > 
> >vdev->priv = vsock;
> >rcu_assign_pointer(the_virtio_vsock, vsock);
> > 
> >mutex_unlock(_virtio_vsock_mutex);
> > 
> > 
> > I worry that this is not the only problem here:
> > seqpacket_allow and setting of vdev->priv at least after
> > device is active look suspicious.
> 
> Right, so if you agree I'll move these before virtio_device_ready().
> 
> > E.g.:
> > 
> > static void virtio_vsock_event_done(struct virtqueue *vq)
> > {
> >struct virtio_vsock *vsock = vq->vdev->priv;
> > 
> >if (!vsock)
> >return;
> >queue_work(virtio_vsock_workqueue, >event_work);
> > }
> > 
> > looks like it will miss events now they will be reported earlier.
> > One might say that since vq has been kicked it might send
> > interrupts earlier too so not a new problem, but
> > there's a chance device actually waits until DRIVER_OK
> > to start operating.
> 
> Yes I see, should I break into 2 patches (one where I move the code already
> present and this one)?
> 
> Maybe a single patch is fine since it's the complete solution.
> 
> Thank you for the detailed explanation,
> Stefano

Two I think since movement can be backported to before the hardening
effort.

-- 
MST

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization


Re: [PATCH net] vsock/virtio: enable VQs early on probe

2022-03-22 Thread Stefano Garzarella

On Tue, Mar 22, 2022 at 09:36:14AM -0400, Michael S. Tsirkin wrote:

On Tue, Mar 22, 2022 at 11:38:23AM +0100, Stefano Garzarella wrote:

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after probe returns, but virtio-vsock
driver uses VQs in the probe function to fill rx and event VQs
with new buffers.



So this is a spec violation. absolutely.


Let's fix this, calling virtio_device_ready() before using VQs
in the probe function.

Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
Signed-off-by: Stefano Garzarella 
---
 net/vmw_vsock/virtio_transport.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 5afc194a58bb..b1962f8cd502 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
INIT_WORK(>event_work, virtio_transport_event_work);
INIT_WORK(>send_pkt_work, virtio_transport_send_pkt_work);

+   virtio_device_ready(vdev);
+
mutex_lock(>tx_lock);
vsock->tx_run = true;
mutex_unlock(>tx_lock);


Here's the whole code snippet:


   mutex_lock(>tx_lock);
   vsock->tx_run = true;
   mutex_unlock(>tx_lock);

   mutex_lock(>rx_lock);
   virtio_vsock_rx_fill(vsock);
   vsock->rx_run = true;
   mutex_unlock(>rx_lock);

   mutex_lock(>event_lock);
   virtio_vsock_event_fill(vsock);
   vsock->event_run = true;
   mutex_unlock(>event_lock);

   if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
   vsock->seqpacket_allow = true;

   vdev->priv = vsock;
   rcu_assign_pointer(the_virtio_vsock, vsock);

   mutex_unlock(_virtio_vsock_mutex);


I worry that this is not the only problem here:
seqpacket_allow and setting of vdev->priv at least after
device is active look suspicious.


Right, so if you agree I'll move these before virtio_device_ready().


E.g.:

static void virtio_vsock_event_done(struct virtqueue *vq)
{
   struct virtio_vsock *vsock = vq->vdev->priv;

   if (!vsock)
   return;
   queue_work(virtio_vsock_workqueue, >event_work);
}

looks like it will miss events now they will be reported earlier.
One might say that since vq has been kicked it might send
interrupts earlier too so not a new problem, but
there's a chance device actually waits until DRIVER_OK
to start operating.


Yes I see, should I break into 2 patches (one where I move the code 
already present and this one)?


Maybe a single patch is fine since it's the complete solution.

Thank you for the detailed explanation,
Stefano

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization


Re: [PATCH net] vsock/virtio: enable VQs early on probe

2022-03-22 Thread Michael S. Tsirkin
On Tue, Mar 22, 2022 at 11:38:23AM +0100, Stefano Garzarella wrote:
> virtio spec requires drivers to set DRIVER_OK before using VQs.
> This is set automatically after probe returns, but virtio-vsock
> driver uses VQs in the probe function to fill rx and event VQs
> with new buffers.


So this is a spec violation. absolutely.

> Let's fix this, calling virtio_device_ready() before using VQs
> in the probe function.
> 
> Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
> Signed-off-by: Stefano Garzarella 
> ---
>  net/vmw_vsock/virtio_transport.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/vmw_vsock/virtio_transport.c 
> b/net/vmw_vsock/virtio_transport.c
> index 5afc194a58bb..b1962f8cd502 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
>   INIT_WORK(>event_work, virtio_transport_event_work);
>   INIT_WORK(>send_pkt_work, virtio_transport_send_pkt_work);
>  
> + virtio_device_ready(vdev);
> +
>   mutex_lock(>tx_lock);
>   vsock->tx_run = true;
>   mutex_unlock(>tx_lock);

Here's the whole code snippet:


mutex_lock(>tx_lock);
vsock->tx_run = true;
mutex_unlock(>tx_lock);

mutex_lock(>rx_lock);
virtio_vsock_rx_fill(vsock);
vsock->rx_run = true;
mutex_unlock(>rx_lock);

mutex_lock(>event_lock);
virtio_vsock_event_fill(vsock);
vsock->event_run = true;
mutex_unlock(>event_lock);

if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
vsock->seqpacket_allow = true;

vdev->priv = vsock;
rcu_assign_pointer(the_virtio_vsock, vsock);

mutex_unlock(_virtio_vsock_mutex);


I worry that this is not the only problem here:
seqpacket_allow and setting of vdev->priv at least after
device is active look suspicious.
E.g.:

static void virtio_vsock_event_done(struct virtqueue *vq)
{
struct virtio_vsock *vsock = vq->vdev->priv;

if (!vsock)
return;
queue_work(virtio_vsock_workqueue, >event_work);
}

looks like it will miss events now they will be reported earlier.
One might say that since vq has been kicked it might send
interrupts earlier too so not a new problem, but
there's a chance device actually waits until DRIVER_OK
to start operating.


> -- 
> 2.35.1

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization


[PATCH net] vsock/virtio: enable VQs early on probe

2022-03-22 Thread Stefano Garzarella
virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after probe returns, but virtio-vsock
driver uses VQs in the probe function to fill rx and event VQs
with new buffers.

Let's fix this, calling virtio_device_ready() before using VQs
in the probe function.

Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko")
Signed-off-by: Stefano Garzarella 
---
 net/vmw_vsock/virtio_transport.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 5afc194a58bb..b1962f8cd502 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
INIT_WORK(>event_work, virtio_transport_event_work);
INIT_WORK(>send_pkt_work, virtio_transport_send_pkt_work);
 
+   virtio_device_ready(vdev);
+
mutex_lock(>tx_lock);
vsock->tx_run = true;
mutex_unlock(>tx_lock);
-- 
2.35.1

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization