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From:   Weilun Du <wdu@google.com>
Date:   Thu, 6 May 2021 15:57:02 -0700
Message-ID: <CAD-gUuAbgons-j_q5TiqjP5ekRtk5cStfi7eLvH8D94WoC4zCQ@mail.gmail.com>
Subject: Re: [PATCH v1] mac80211_hwsim: add concurrent channels scanning
 support over virtio
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, kernel-team@android.com,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Thu, May 6, 2021 at 2:13 PM Johannes Berg <johannes@sipsolutions.net> wrote:
>
> On Thu, 2021-05-06 at 14:11 -0700, Weilun Du wrote:
> > On Thu, May 6, 2021 at 11:19 AM Johannes Berg <johannes@sipsolutions.net> wrote:
> > >
> > > On Thu, 2021-05-06 at 11:05 -0700, Weilun Du wrote:
> > > > This fixed the crash when setting channels to 2 or more when
> > > > communicating over virtio.
> > >
> > > Interesting, I thought I was probably the only user of virtio? :)
> > >
> > > johannes
> > >
> > Hi Johannes,
> > Actually, Android Emulator uses mac80211_hwsim for wifi simulation
> > over virtio and it's working. This patch fixed the crash when we set
> > channels=2 to speed up scanning. I am trying to see if it makes sense
> > to upstream this patch since it's not Android-specific. Thanks!
> >
> Oh sure, I'll take a look and will probably apply it for the next cycle,
> haven't done an in-depth review. I was just surprised somebody actually
> *used* the virtio thing :-)
>
> Does that mean virt_wifi isn't used anymore by the Android emulator?
> Maybe then we should remove that again, it had some obscure bugs that
> syzkaller found? Not that I mind it being around much, but ...
>
> johannes
>

Thanks for looking into it. Actually, virt_wifi is still in use. There
are two different emulators that target different use cases. Android
emulator (goldfish) is mainly for third-party app developers. But yes
eventually, we are going to converge the Wi-Fi solution.