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From: Peter Maydell <peter.maydell@linaro.org>
To: Jason Wang <jasowang@redhat.com>
Cc: Dmitry Fleytman <dmitry.fleytman@gmail.com>,
	"Michael S. Tsirkin" <mst@redhat.com>, Li Qiang <liq3ea@163.com>,
	Li Qiang <liq3ea@gmail.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Alexander Bulekov <alxndr@bu.edu>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 2/2] e1000e: make TX reentrant
Date: Thu, 23 Jul 2020 11:36:47 +0100	[thread overview]
Message-ID: <CAFEAcA-XHFXBeQ9qp91T_gzNqyxEEDz_caHanwMuYRjKjEocWQ@mail.gmail.com> (raw)
In-Reply-To: <20200722085747.6514-2-jasowang@redhat.com>

On Wed, 22 Jul 2020 at 10:00, Jason Wang <jasowang@redhat.com> wrote:
>
> In loopback mode, e1000e RX can DMA into TX doorbell which requires
> TX to be reentrant. This patch make e1000e's TX routine reentrant by
> introducing a per device boolean for recording whether or not a TX
> rountine is being called and return early.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---

This feels like a sticking-plaster fix that's not really in the
right place... It stops us from calling back into
e1000e_start_xmit(), but it doesn't prevent a DMA request
from touching other device registers that update state in
the E100ECore struct that the transmit code is not expecting
to change.

thanks
-- PMM


  parent reply	other threads:[~2020-07-23 10:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22  8:57 [PATCH 1/2] net: forbid the reentrant RX Jason Wang
2020-07-22  8:57 ` [PATCH 2/2] e1000e: make TX reentrant Jason Wang
2020-07-22 11:24   ` Li Qiang
2020-07-23  2:22     ` Jason Wang
2020-07-22 12:53   ` Michael Tokarev
2020-07-23  2:25     ` Jason Wang
2020-07-23 12:01       ` Stefan Hajnoczi
2020-07-23 10:36   ` Peter Maydell [this message]
2020-07-24  4:00     ` Jason Wang
2020-07-28  4:00 ` [PATCH 1/2] net: forbid the reentrant RX Jason Wang
2020-09-02 15:56   ` Alexander Bulekov
2020-09-03  3:56     ` Jason Wang
2020-09-03  4:02       ` Alexander Bulekov

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