Re: [Qemu-devel] [PATCH RFC] e1000: defer packets until BM enabled

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Dec 01, 2014 at 06:01:18PM +0000, Gabriel Somlo wrote:
> Hi Michael,
> 
> I had to make some small changes to get this patch to build successfully,
> see inline below:

Ouch, looks like I sent out a stale version:
git commit
build+edit
git format-patch (without git commit)

Happens to me now and again :(

Sorry.

> On Monday, December 01, 2014 11:50am, Michael S. Tsirkin [mst@redhat.com] wrote:
> > 
> > Some guests seem to set BM for e1000 after
> > enabling RX.
> > If packets arrive in the window, device is wedged.
> > Probably works by luck on real hardware, work around
> > this by making can_receive depend on BM.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  hw/net/e1000.c | 20 +++++++++++++++++++-
> >  1 file changed, 19 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> > index e33a4da..34625ac 100644
> > --- a/hw/net/e1000.c
> > +++ b/hw/net/e1000.c
> > @@ -923,7 +923,9 @@ e1000_can_receive(NetClientState *nc)
> >      E1000State *s = qemu_get_nic_opaque(nc);
> > 
> >      return (s->mac_reg[STATUS] & E1000_STATUS_LU) &&
> > -        (s->mac_reg[RCTL] & E1000_RCTL_EN) && e1000_has_rxbufs(s, 1);
> > +        (s->mac_reg[RCTL] & E1000_RCTL_EN) &&
> > +        (s->parent_obj.config[PCI_COMMAND] & PCI_COMMAND_MASTER) &&
> > +        e1000_has_rxbufs(s, 1);
> >  }
> > 
> >  static uint64_t rx_desc_base(E1000State *s)
> > @@ -1529,6 +1531,20 @@ static NetClientInfo net_e1000_info = {
> >      .link_status_changed = e1000_set_link_status,
> >  };
> > 
> > +static void e1000_write_config(PCIDevice *pci_dev, uint32_t address,
> > +                                uint32_t val, int len)
> > +{
> > +    E1000State *d = E1000(dev);
> 
> s/dev/pci_dev/
> 
> > +
> > +    pci_default_write_config(pci_dev, address, val, len);
> > +
> > +    if (range_covers_byte(address, len, PCI_COMMAND) &&
> 
> requires #include "qemu/range.h" at the top of e1000.c
> 
> > +        (pci_dev->config[PCI_COMMAND] & PCI_COMMAND_MASTER)) {
> > +        qemu_flush_queued_packets(qemu_get_queue(s->nic));
> 
> s/s->nic/d->nic/
> 
> > +    }
> > +}
> > +
> > +
> >  static int pci_e1000_init(PCIDevice *pci_dev)
> >  {
> >      DeviceState *dev = DEVICE(pci_dev);
> > @@ -1539,6 +1555,8 @@ static int pci_e1000_init(PCIDevice *pci_dev)
> >      int i;
> >      uint8_t *macaddr;
> > 
> > +    pci_dev->config_write = e1000_write_config;
> > +
> >      pci_conf = pci_dev->config;
> > 
> >      /* TODO: RST# value should be 0, PCI spec 6.2.4 */
> > --
> 
> With this, I can confirm everything still works fine on both Mavericks and
> F21-beta-live. So:
> 
> Tested-by: Gabriel Somlo <somlo@cmu.edu>
> 
> Regards,
> --Gabriel

Thanks!