Re: [PATCH 1/2] net: forbid the reentrant RX

[Alexander Bulekov <alxndr@bu.edu>]

On 200903 1156, Jason Wang wrote:
> 
> On 2020/9/2 下午11:56, Alexander Bulekov wrote:
> > On 200728 1200, Jason Wang wrote:
> > > On 2020/7/22 下午4:57, Jason Wang wrote:
> > > > The memory API allows DMA into NIC's MMIO area. This means the NIC's
> > > > RX routine must be reentrant. Instead of auditing all the NIC, we can
> > > > simply detect the reentrancy and return early. The queue->delivering
> > > > is set and cleared by qemu_net_queue_deliver() for other queue helpers
> > > > to know whether the delivering in on going (NIC's receive is being
> > > > called). We can check it and return early in qemu_net_queue_flush() to
> > > > forbid reentrant RX.
> > > > 
> > > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > > ---
> > > >    net/queue.c | 3 +++
> > > >    1 file changed, 3 insertions(+)
> > > > 
> > > > diff --git a/net/queue.c b/net/queue.c
> > > > index 0164727e39..19e32c80fd 100644
> > > > --- a/net/queue.c
> > > > +++ b/net/queue.c
> > > > @@ -250,6 +250,9 @@ void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
> > > >    bool qemu_net_queue_flush(NetQueue *queue)
> > > >    {
> > > > +    if (queue->delivering)
> > > > +        return false;
> > > > +
> > > >        while (!QTAILQ_EMPTY(&queue->packets)) {
> > > >            NetPacket *packet;
> > > >            int ret;
> > > 
> > > Queued for rc2.
> > > 
> > > Thanks
> > > 
> > Hi Jason,
> > I don't think this ever made it in. Are there any remaining problems?
> > Thanks
> > -Alex
> 
> 
> Hi Alex:
> 
> It should have been merged:
> 
> https://git.qemu.org/?p=qemu.git;a=commit;h=22dc8663d9fc7baa22100544c600b6285a63c7a3
> 
> Thanks
> 

Ah. I missed only 1/2 was queued. I guess the e1000 patch didn't make
the cut..
Thanks
-Alex

> 
> > 
>