Re: [Qemu-devel] [PATCH v2 2/4] net/vmxnet3: return correct value for VMXNET3_CMD_GET_DID_* command

[Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>]

Hi,

On Mon, 21 Dec 2015 22:18:22 -0800 Miao Yan <yanmiaobest@gmail.com> wrote:
> VMXNET3_CMD_GET_DID_LO should return PCI ID of the device
> and VMXNET3_CMD_GET_DID_HI should return vmxnet3 revision ID.
> 
> This behavior can be observed by the following steps:
> 
> 1) run a Linux distro on esxi server
> 2) modify vmxnet3 Linux driver to read DID_HI and DID_LO:
> 
>   VMXNET3_WRITE_BAR1_REG(adapter, VMXNET3_REG_CMD, VMXNET3_CMD_GET_DID_LO);
>   lo =  VMXNET3_READ_BAR1_REG(adapter, VMXNET3_REG_CMD);
> 
>   VMXNET3_WRITE_BAR1_REG(adapter, VMXNET3_REG_CMD, VMXNET3_CMD_GET_DID_HI);
>   high =  VMXNET3_READ_BAR1_REG(adapter, VMXNET3_REG_CMD);
>   pr_info("vmxnet3 DID lo: 0x%x, high: 0x%x\n", lo, high);
> 
> The kernel log will have something like the following message:
> 
>   [ 7005.111170] vmxnet3 DID lo: 0x7b0, high: 0x1

[...]

> +    case VMXNET3_CMD_GET_DID_HI:
> +        ret = VMXNET3_DEVICE_REVISION;
> +        break;
> +

Do we know whether VMXNET3_DEVICE_REVISION needs to be returned, or
should it be VMXNET3_DEVICE_VERSION instead?

I see both are currently defined as 1, but I assume this could
potentially be changed in the future.

How can we tell what's the right semantics for VMXNET3_CMD_GET_DID_HI?

Regards,
Shmulik