Re: [PATCH 2/3] hw/net: e1000e: Correct the initial value of VET register

[Jason Wang <jasowang@redhat.com>]

在 2021/7/2 下午12:43, Bin Meng 写道:
> On Fri, Jul 2, 2021 at 11:29 AM Jason Wang <jasowang@redhat.com> wrote:
>>
>> 在 2021/7/1 下午5:46, 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 e1000e 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.
>>>
>>> Unlike e1000 in QEMU, e1000e uses a field 'vet' in "struct E1000Core"
>>> to cache the value of VET register, but the cache only gets updated
>>> when VET register is written. To always get a consistent VET value
>>> no matter VET is written or remains its reset value, drop the 'vet'
>>> field and use 'core->mac[VET]' directly.
>>>
>>> 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>
>>> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
>>> ---
>>>
>>>    hw/net/e1000e_core.h |  2 --
>>>    hw/net/e1000e.c      |  6 ++----
>>>    hw/net/e1000e_core.c | 11 ++++++-----
>>>    3 files changed, 8 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/hw/net/e1000e_core.h b/hw/net/e1000e_core.h
>>> index 4ddb4d2c39..07d722bc68 100644
>>> --- a/hw/net/e1000e_core.h
>>> +++ b/hw/net/e1000e_core.h
>>> @@ -105,8 +105,6 @@ struct E1000Core {
>>>        uint32_t itr_guest_value;
>>>        uint32_t eitr_guest_value[E1000E_MSIX_VEC_NUM];
>>>
>>> -    uint16_t vet;
>>> -
>>>        uint8_t permanent_mac[ETH_ALEN];
>>>
>>>        NICState *owner_nic;
>>> diff --git a/hw/net/e1000e.c b/hw/net/e1000e.c
>>> index a8a77eca95..1797e4a7cb 100644
>>> --- a/hw/net/e1000e.c
>>> +++ b/hw/net/e1000e.c
>>> @@ -602,8 +602,8 @@ static const VMStateDescription e1000e_vmstate_intr_timer = {
>>>
>>>    static const VMStateDescription e1000e_vmstate = {
>>>        .name = "e1000e",
>>> -    .version_id = 1,
>>> -    .minimum_version_id = 1,
>>> +    .version_id = 2,
>>> +    .minimum_version_id = 2,
>>>        .pre_save = e1000e_pre_save,
>>>        .post_load = e1000e_post_load,
>>>        .fields = (VMStateField[]) {
>>> @@ -645,8 +645,6 @@ static const VMStateDescription e1000e_vmstate = {
>>>            VMSTATE_UINT32_ARRAY(core.eitr_guest_value, E1000EState,
>>>                                 E1000E_MSIX_VEC_NUM),
>>>
>>> -        VMSTATE_UINT16(core.vet, E1000EState),
>>
>> This is not the suggested way. We'd better not bump version in this case.
>>
>> How about update vet during post_load?
> But core.vet is removed in this patch. Not sure how to handle this?


Keep using core.vet, sync core.vet with mac[VET] during post_load.

Thanks


>
> Regards,
> Bin
>