On 30 September 2017 at 01:17, Philippe Mathieu-Daudé <f4...@amsat.org> wrote:
> Hi Andrey,
>
> On 09/18/2017 04:50 PM, Andrey Smirnov wrote:
>>
>> Frame truncation length, TRUNC_FL, is determined by the contents of
>> ENET_FTRL register, so convert the code to use it instead of a
>> hardcoded constant.
>>
>> Cc: Peter Maydell <peter.mayd...@linaro.org>
>> Cc: Jason Wang <jasow...@redhat.com>
>> Cc: qemu-devel@nongnu.org
>> Cc: qemu-...@nongnu.org
>> Cc: yurov...@gmail.com
>> Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
>> ---
>> hw/net/imx_fec.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
>> index 767402909d..989c11be5f 100644
>> --- a/hw/net/imx_fec.c
>> +++ b/hw/net/imx_fec.c
>> @@ -1050,8 +1050,8 @@ static ssize_t imx_enet_receive(NetClientState *nc,
>> const uint8_t *buf,
>> size += 4;
>> /* Huge frames are truncted. */
>> - if (size > ENET_MAX_FRAME_SIZE) {
>> - size = ENET_MAX_FRAME_SIZE;
>> + if (size > s->regs[ENET_FTRL]) {
>> + size = s->regs[ENET_FTRL]; > flags |= ENET_BD_TR |
>> ENET_BD_LG;
>> }
>
>
> for this to be ok you need to update imx_enet_write(), such:
>
> case ENET_FTRL:
> - s->regs[index] = value & 0x00003fff;
> + value &= 0x00003fff;
> + if (value > ENET_MAX_FRAME_SIZE) {
> + warn_report("%s: guest requested bigger "
> + "frame size than QEMU supports "
> + "(%u > %u)", value,
> + ENET_MAX_FRAME_SIZE);
> + value = ENET_MAX_FRAME_SIZE;
> + }
> + s->regs[index] = value;
> break;
Yes, and also an incoming-migration post_load callback that
fails migration if the value is too large.
It might be simpler to truncate to the smaller of the ENET_FTRL
register value and ENET_MAX_FRAME_SIZE.
(PS: what is the hardware behaviour if ENET_FTRL is set to
a larger value than ENET_MAX_FRAME_SIZE ?)
thanks
-- PMM
