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

[Jason Wang]

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