Re: [Qemu-devel] [PATCH for-1.4] e1000: unbreak the guest network migration to 1.3

[Michael S. Tsirkin]

On Thu, Feb 14, 2013 at 01:50:04PM -0600, Anthony Liguori wrote:
> "Michael S. Tsirkin" <address@hidden> writes:
> 
> > QEMU 1.3 does not emulate the link auto negotiation, so if migrate to a
> > 1.3 machine during link auto negotiation, the guest link will be set to 
> > down.
> > Fix this by just disabling auto negotiation for 1.3.
> >
> > Signed-off-by: Michael S. Tsirkin <address@hidden>
> > ---
> >  hw/e1000.c   | 25 +++++++++++++++++++++++++
> >  hw/pc_piix.c |  4 ++++
> >  2 files changed, 29 insertions(+)
> >
> > diff --git a/hw/e1000.c b/hw/e1000.c
> > index d6fe815..263f2f4 100644
> > --- a/hw/e1000.c
> > +++ b/hw/e1000.c
> > @@ -131,6 +131,11 @@ typedef struct E1000State_st {
> >      } eecd_state;
> >  
> >      QEMUTimer *autoneg_timer;
> > +
> > +/* Enabled compatibility for migration to/from rhel6.3.0 and older */
> 
> I presume you mean QEMU 1.3...

Yack.

> > +#define E1000_FLAG_QEMU_13_BIT 0
> > +#define E1000_FLAG_QEMU_13 (1 << E1000_FLAG_QEMU_13_BIT)
> > +    uint32_t compat_flags;
> >  } E1000State;
> >  
> >  #define    defreg(x)       x = (E1000_##x>>2)
> > @@ -165,6 +170,14 @@ e1000_link_up(E1000State *s)
> >  static void
> >  set_phy_ctrl(E1000State *s, int index, uint16_t val)
> >  {
> > +    /*
> > +     * QEMU 1.3 does not support link auto-negotiation emulation, so if we
> > +     * migrate during auto negotiation, after migration the link will be
> > +     * down.
> > +     */
> > +    if (s->compat_flags & E1000_FLAG_QEMU_13) {
> > +        return;
> > +    }
> >      if ((val & MII_CR_AUTO_NEG_EN) && (val & MII_CR_RESTART_AUTO_NEG)) {
> >          e1000_link_down(s);
> >          s->phy_reg[PHY_STATUS] &= ~MII_SR_AUTONEG_COMPLETE;
> > @@ -1120,6 +1133,11 @@ static void e1000_pre_save(void *opaque)
> >  {
> >      E1000State *s = opaque;
> >      NetClientState *nc = qemu_get_queue(s->nic);
> > +
> > +    if (s->compat_flags & E1000_FLAG_QEMU_13) {
> > +        return;
> > +    }
> > +
> >      /*
> >       * If link is down and auto-negotiation is ongoing, complete
> >       * auto-negotiation immediately.  This allows is to look at
> > @@ -1141,6 +1159,11 @@ static int e1000_post_load(void *opaque, int 
> > version_id)
> >       * to link status bit in mac_reg[STATUS].
> >       * Alternatively, restart link negotiation if it was in progress. */
> >      nc->link_down = (s->mac_reg[STATUS] & E1000_STATUS_LU) == 0;
> > +
> > +    if (s->compat_flags & E1000_FLAG_QEMU_13) {
> > +        return 0;
> > +    }
> > +
> >      if (s->phy_reg[PHY_CTRL] & MII_CR_AUTO_NEG_EN &&
> >          s->phy_reg[PHY_CTRL] & MII_CR_RESTART_AUTO_NEG &&
> >          !(s->phy_reg[PHY_STATUS] & MII_SR_AUTONEG_COMPLETE)) {
> > @@ -1343,6 +1366,8 @@ static void qdev_e1000_reset(DeviceState *dev)
> >  
> >  static Property e1000_properties[] = {
> >      DEFINE_NIC_PROPERTIES(E1000State, conf),
> > +    DEFINE_PROP_BIT("x-qemu_13_compat", E1000State,
> > +                    compat_flags, E1000_FLAG_QEMU_13, false),
> >      DEFINE_PROP_END_OF_LIST(),
> 
> Would it make more sense to simply call this auto-negotiation?

Okay.

> Regards,
> 
> Anthony Liguori
> 
> >  };
> >  
> > diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> > index ba09714..89a3f1f 100644
> > --- a/hw/pc_piix.c
> > +++ b/hw/pc_piix.c
> > @@ -537,6 +537,10 @@ static QEMUMachine pc_machine_v0_13 = {
> >              .driver   = "vmware-svga",
> >              .property = "rombar",
> >              .value    = stringify(0),
> > +        },{
> > +            .driver   = "e1000",
> > +            .property = "x-qemu_13_compat",
> > +            .value    = "on",
> >          },
> >          { /* end of list */ }
> >      },
> > -- 
> > MST