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

[Anthony Liguori]

"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...

> +#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?

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