Re: [Qemu-devel] [PATCH] e1000: pre-initialize RAH/RAL registers

[Stefan Hajnoczi <stefanha@gmail.com>]

On Tue, Oct 30, 2012 at 01:20:40PM -0400, Gabriel L. Somlo wrote:
> Some guest operating systems' drivers (Mac OS X in particular) fail to
> properly initialize the Receive Address registers (probably expecting
> them to be pre-initialized by an earlier component, such as a proprietary
> BIOS). This patch pre-initializes the RA registers, allowing OS X
> networking to function properly. Other guest operating systems are not
> affected, and free to (re)initialize these registers during boot.
> 
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> ---
>  hw/e1000.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/e1000.c b/hw/e1000.c
> index e4f1ffe..6478ff3 100644
> --- a/hw/e1000.c
> +++ b/hw/e1000.c
> @@ -278,6 +278,10 @@ static void e1000_reset(void *opaque)
>      if (d->nic->nc.link_down) {
>          e1000_link_down(d);
>      }
> +
> +  /* Some guests expect pre-initialized RAH/RAL (AddrValid flag + MACaddr) */
> +  d->mac_reg[RA+1] = E1000_RAH_AV;

Please use 4 space indentation (QEMU coding style).

> +  memmove(&d->mac_reg[RA], &d->conf.macaddr, sizeof(struct MACAddr));

When the host is big-endian the filter code will byteswap and the MAC address
will not match:

  for (rp = s->mac_reg + RA; rp < s->mac_reg + RA + 32; rp += 2) {
      if (!(rp[1] & E1000_RAH_AV))
          continue;
      ra[0] = cpu_to_le32(rp[0]);
      ra[1] = cpu_to_le32(rp[1]);
      if (!memcmp(buf, (uint8_t *)ra, 6)) {

Stefan