Re: [PATCH v2 1/3] hw/net: e1000: Correct the initial value of VET register

[Jason Wang <jasowang@redhat.com>]

在 2021/7/2 下午5:24, Bin Meng 写道:
> From: Christina Wang <christina.wang@windriver.com>
>
> The initial value of VLAN Ether Type (VET) register is 0x8100, as per
> the manual and real hardware.
>
> While Linux e1000 driver always writes VET register to 0x8100, it is
> not always the case for everyone. Drivers relying on the reset value
> of VET won't be able to transmit and receive VLAN frames in QEMU.
>
> Reported-by: Markus Carlstedt <markus.carlstedt@windriver.com>
> Signed-off-by: Christina Wang <christina.wang@windriver.com>
> Signed-off-by: Bin Meng <bin.meng@windriver.com>
> ---
>
> (no changes since v1)
>
>   hw/net/e1000.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> index 4f75b44cfc..20cbba6411 100644
> --- a/hw/net/e1000.c
> +++ b/hw/net/e1000.c
> @@ -29,6 +29,7 @@
>   #include "hw/pci/pci.h"
>   #include "hw/qdev-properties.h"
>   #include "migration/vmstate.h"
> +#include "net/eth.h"
>   #include "net/net.h"
>   #include "net/checksum.h"
>   #include "sysemu/sysemu.h"
> @@ -254,6 +255,7 @@ static const uint32_t mac_reg_init[] = {
>       [MANC]    = E1000_MANC_EN_MNG2HOST | E1000_MANC_RCV_TCO_EN |
>                   E1000_MANC_ARP_EN | E1000_MANC_0298_EN |
>                   E1000_MANC_RMCP_EN,
> +    [VET]     = ETH_P_VLAN,


I wonder if we need a compat flag for this, since we change the behavior.

(See e1000_properties[])

Thanks


>   };
>   
>   /* Helper function, *curr == 0 means the value is not set */