Re: [PATCH] hw/net/imx_fec: return 0xffff when accessing non-existing PHY

[Jason Wang <jasowang@redhat.com>]

在 2021/5/3 上午12:14, Guenter Roeck 写道:
> On 5/2/21 9:09 AM, Bin Meng wrote:
>> On Mon, May 3, 2021 at 12:03 AM Guenter Roeck <linux@roeck-us.net> wrote:
>>> If a PHY does not exist, attempts to read from it should return 0xffff.
>>> Otherwise the Linux kernel will believe that a PHY is there and select
>>> the non-existing PHY. This in turn will result in network errors later
>>> on since the real PHY is not selected or configured.
>>>
>>> Since reading from or writing to a non-existing PHY is not an emulation
>>> error, replace guest error messages with traces.
>>>
>>> Fixes: 461c51ad4275 ("Add a phy-num property to the i.MX FEC emulator")
>>> Cc: Jean-Christophe Dubois <jcd@tribudubois.net>
>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>> ---
>>>   hw/net/imx_fec.c    | 8 +++-----
>>>   hw/net/trace-events | 2 ++
>>>   2 files changed, 5 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
>>> index f03450c028..9c7035bc94 100644
>>> --- a/hw/net/imx_fec.c
>>> +++ b/hw/net/imx_fec.c
>>> @@ -283,9 +283,8 @@ static uint32_t imx_phy_read(IMXFECState *s, int reg)
>>>       uint32_t phy = reg / 32;
>>>
>>>       if (phy != s->phy_num) {
>>> -        qemu_log_mask(LOG_GUEST_ERROR, "[%s.phy]%s: Bad phy num %u\n",
>>> -                      TYPE_IMX_FEC, __func__, phy);
>>> -        return 0;
>>> +        trace_imx_phy_read_num(phy, s->phy_num);
>>> +        return 0xffff;
>>>       }
>>>
>>>       reg %= 32;
>>> @@ -345,8 +344,7 @@ static void imx_phy_write(IMXFECState *s, int reg, uint32_t val)
>>>       uint32_t phy = reg / 32;
>>>
>>>       if (phy != s->phy_num) {
>>> -        qemu_log_mask(LOG_GUEST_ERROR, "[%s.phy]%s: Bad phy num %u\n",
>>> -                      TYPE_IMX_FEC, __func__, phy);
>>> +        trace_imx_phy_write_num(phy, s->phy_num);
>>>           return;
>>>       }
>>>
>>> diff --git a/hw/net/trace-events b/hw/net/trace-events
>>> index baf25ffa7e..ee77238d9e 100644
>>> --- a/hw/net/trace-events
>>> +++ b/hw/net/trace-events
>>> @@ -413,8 +413,10 @@ i82596_set_multicast(uint16_t count) "Added %d multicast entries"
>>>   i82596_channel_attention(void *s) "%p: Received CHANNEL ATTENTION"
>>>
>>>   # imx_fec.c
>>> +imx_phy_read_num(int phy, int configured) "read request from unconfigured phy %d (configured %d)"
>> nits: could we put this below imx_phy_read(), like you put
>> imx_phy_write_num after imx_phy_write?
>>
> Sure, makes sense. I'll wait a bit for other feedback and then resend.


Ok, please send V2.

Thanks


>
>>>   imx_phy_read(uint32_t val, int phy, int reg) "0x%04"PRIx32" <= phy[%d].reg[%d]"
>>>   imx_phy_write(uint32_t val, int phy, int reg) "0x%04"PRIx32" => phy[%d].reg[%d]"
>>> +imx_phy_write_num(int phy, int configured) "write request to unconfigured phy %d (configured %d)"
>>>   imx_phy_update_link(const char *s) "%s"
>>>   imx_phy_reset(void) ""
>>>   imx_fec_read_bd(uint64_t addr, int flags, int len, int data) "tx_bd 0x%"PRIx64" flags 0x%04x len %d data 0x%08x"
>>> --
>> Otherwise,
>> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
>> Tested-by: Bin Meng <bmeng.cn@gmail.com>
>>
> Thanks!
>
> Guenter
>