Re: [PATCH 1/3] efinet: handle get_status() properly

[Andrei Borzenkov]

В Wed, 5 Aug 2015 14:36:37 -0400
Josef Bacik <address@hidden> пишет:

> The EFI SNP documentation isn't super clear on the value that is returned in
> txbuf when calling into GetStatus.  The documentation says its the pointer to
> the recycle buffer, but the documentation for Transmit() says that it should 
> be
> the pointer to the buffer that we transmitted.

Actually it says "Recycled transmit buffer address" and further
"GetStatus() until the transmitted buffer shows up in the recycled
transmit buffer" so it looks reasonably clear to me.

>                                               On the boxes I'm using it's just
> a random pointer (usually 0x1).  It is definitely transmitting stuff, but the
> get_status call is not returning the pointer to the txbuf we passed in.

Which sounds like firmware bug. To be sure - you observe it also using
current GIT master?

>                                                                        Looking
> at a few EFI implementations and other SNP drivers it seems like there is
> confusion everywhere on this.  So since we only transmit one buffer at a time,
> just assume that a non-NULL txbuf means that our transmit happened properly.
> With this patch I can now do networking on our EFI enabled boxes.  Thanks,
> 
> cc: Peter Jones <address@hidden>
> Signed-off-by: Josef Bacik <address@hidden>
> ---
>  grub-core/net/drivers/efi/efinet.c | 13 +++----------
>  1 file changed, 3 insertions(+), 10 deletions(-)
> 
> diff --git a/grub-core/net/drivers/efi/efinet.c 
> b/grub-core/net/drivers/efi/efinet.c
> index f27a117..4d3f8aa 100644
> --- a/grub-core/net/drivers/efi/efinet.c
> +++ b/grub-core/net/drivers/efi/efinet.c
> @@ -47,19 +47,11 @@ send_card_buffer (struct grub_net_card *dev,
>       if (st != GRUB_EFI_SUCCESS)
>         return grub_error (GRUB_ERR_IO,
>                            N_("couldn't send network packet"));
> -     if (txbuf == dev->txbuf)
> +     if (txbuf)
>         {
>           dev->txbusy = 0;
>           break;
>         }
> -     if (txbuf)
> -       {
> -         st = efi_call_7 (net->transmit, net, 0, dev->last_pkt_size,
> -                          dev->txbuf, NULL, NULL, NULL);
> -         if (st != GRUB_EFI_SUCCESS)
> -           return grub_error (GRUB_ERR_IO,
> -                              N_("couldn't send network packet"));
> -       }
>       if (limit_time < grub_get_time_ms ())
>         return grub_error (GRUB_ERR_TIMEOUT,
>                            N_("couldn't send network packet"));
> @@ -84,8 +76,9 @@ send_card_buffer (struct grub_net_card *dev,
>       we run in the GRUB_ERR_TIMEOUT case above.
>       Perhaps a timeout in the FW has discarded the recycle buffer.
>     */
> +  txbuf = NULL;
>    st = efi_call_3 (net->get_status, net, 0, &txbuf);
> -  dev->txbusy = !(st == GRUB_EFI_SUCCESS && txbuf == dev->txbuf);
> +  dev->txbusy = !(st == GRUB_EFI_SUCCESS && txbuf);
>  
>    return GRUB_ERR_NONE;
>  }